Exercise Physiology Final
The possible increase in 2;3 DPG in highly trained athletes support an
adaptive response that augments oxygen delivery to active tissue.
A sports drink containing some sodium is
adequate.
The higher hemoglobin levels in men partly account for their higher
aerobic capacities relative to
Hematocrit levels are often a measure of
aerobic capacity in athletes.
When hemoglobin binds to oxygen at the lungs hemoglobin loses its
affinity for H+ and there is a change in the structure of the hemoglobin molecule which causes carbon dioxide to be released from hemoglobin.
2;3 DPG binds to hemoglobin which lowers the
affinity of hemoglobin to oxygen and allows hemoglobin to release some of its bound oxygen for the working muscles.
Again lung volumes are dependent upon
age; gender; body size; and height rather than on exercise training.
About 10% of the lungs is tissue with the remainder filled with
air and blood.
1. Rest: TV is approximately 0.5 L of air for each breath and breathing rate is approximately
12
Rest VE =
12 breaths/min x 0.5 L air/breath = 6.0 L air/min
One study showed that the oxygen cost of breathing decreased between
13 and 79% after one day of smoking abstinence.
Studies have shown that the oxygen content in the exhaled breath of trained individuals is approximately
14% to 15% whereas the oxygen content in untrained individuals is approximately 18%.
Maximum Voluntary Ventilation (MVV) involves
15 seconds of fast deep breathing.
skeletal muscle
15% to 20%. During exercise ___ of blood flow travels to skeletal muscle,80% to 85%
At maximum exercise trained Stroke volume is
179ml/b
The anatomical dead space is the area of the lung prior to the
17th generation of bronchioles
Anatomical dead space is the area of the lungs prior to the
17th generation of bronchioles where
One study showed that
18% of Ironman finishers were hyponatremic.
At maximum exercise trained HR is
195b/min
At maximum exercise untrained HR is
195b/min
The average sodium loss during the Ironman Triathlon is about
1;000 mg/hour - the range is between 700 mg and 2;500 mg sodium loss/hour.
1. Females: 12-14 g Hb/100 ml blood
2. Males: 14-16 g Hb/100 ml blood
In this regard ____of healthy firemen studied developed ischemia at the onset of strenuous exercise in the absence of a warm-up
2/3rds .
Oxygen
20% and 159 partial pressure
At maximum exercise untrained Cardiac output is
22000ml/min
Women have approximately ___% lower values for stroke volume relative to men due to smaller overall body size
25
Blood has an osmolality between
280 and 330 (mOsm/kg).
Partial pressure of oxygen in muscle during exercise
3
2
3 DPG is produced during the, anaerobic process of glycolysis in red blood cells (i.e., red blood
2
3-diphosphoglycerate (2,3 DPG) also shifts the oxyhemoglobin dissociation curve to the ,
In athletes who experience EIH the pressure difference between alveolar PO2 and arterial PO2 can increase to
30 mm Hg or more.
Exercise-induced asthma occurs in
30% to 50% of those with allergic rhinitis and hay fever, and
Cigarette Smoking: Airway resistance triples and lasts for
35 minutes after 15 inhalations of
Exercise VE =
35-60 breaths/ min x 2.0-3.0 L air/breath = 70 L air - 180 L air /Min
At maximum exercise trained cardiac output is
35000ml/min
Athletes who lose 1 liter of fluid per hour need to consume
4 cups of fluid per hour which can be difficult to do.
The lifespan of RBC's is about
4 months.
Partial pressure of carbon dioxide in blood at rest
40
Partial pressure of carbon dioxide in blood during exercise
40
Partial pressure of oxygen in muscle at rest
40
In severe COPD up to
40% of the total VO2 can go to the respiratory muscles.
Stroke volume reaches maximum levels at approximately
40-50% of mVO2 (or 40-50% max heart rate) in both trained and untrained individuals.
Energy gels only contain
40-55 mg/gel and Powerbar contains 95 mg/bar.
In the paper he recommended that marathoners drink
400 to 800 milliliters/hour.
Partial pressure of carbon dioxide in muscle at rest
46
Myoglobin releases most of its bound oxygen at PO2 levels less than
5 mm Hg.
From this you can plan how much to drink every 1
5 to 20 minutes while running a marathon (15-16 fluid ounces for every pound lost).
Heart rate was ___ lower during exercise after a day of abstinence from cigarette smoking compared to immediately after smoking
5 to 7%.
Trained HR at rest
50 b/min
If the lung tissue was spread out it would span an area of
50 to 100 meters; the size of half a tennis court (Figure 12.2).
In untrained individuals the anaerobic threshold (i.e. when lactic acid accumulates in physically active tissues) occurs around
50% of their mVO2.
The diffusion gradient for carbon dioxide between the muscle cells and blood during exercise is
50.
Trained Cardiac Output at rest
5000 ml/min
Untrained Cardiac Output at rest
5000 ml/min
The formed components makeup 40% to 45% of blood and the plasma make
55% to 60% of blood (See Hematocrit Figure).
Gatorade's carbohydrate concentration is
6%.
*The diffusion gradient for carbon dioxide between the muscle cells and blood at rest is
6.
Ejection fraction in a normal heart at rest:
60% - 65% (i.e, 35% - 40% of blood remains in the heart after contraction).
Gas exchange becomes impossible when the physiological dead space is greater than
60% of total lung volume.
*The diffusion gradient for oxygen between the blood and cells at rest is
60.
Carbohydrate and fluid requirements can be met by drinking between
625 to 1250 ml of fluid
Another study showed that submaximum heart rate decreased and time to exhaustion increased after __ days abstinence from cigarette smoking
7
Untrained HR at rest
70 b/min
Because water vapor exerts a partial pressure of 47 mm Hg the total pressure exerted by dry inspired air is
713 mm Hg (760 - 47 = 713).
Untrained Stroke Volume at rest
71ml/b
The total pressure of atmospheric air is
760 mm Hg.
Nitrogen
79.04% and 600 partial pressure
Gastric emptying is slowed when consuming
8% carbohydrate.
The respiratory muscles require 3% to 5% of the total VO2 (O2 intake) during moderate exercise and
8% to 10% of the total VO2 during higher intensity exercise.
Partial pressure of carbon dioxide in muscle during exercise
90
This causes oxygen saturated to fall below
90% and arterial PO2 to fall below 75 mm Hg.
Genetics are responsible for approximately
90% of mVO2.
By contrast the anaerobic threshold of highly fit endurance athletes is approximately
90% of their mVO2.
Plasma is made up of
90% water; 7% plasma protein; and 3% nutrients; electrolytes ;hormones enzymes; antibodies; and other substances.
The diffusion gradient for oxygen between the blood and cells during exercise is
97.
Red blood cells (RBC's) called erythrocytes make up
99% and white blood cells (WBC's) and
Indicator Dilution Method
: CO = Quantity of Dye Injected/ Average Concentration Dye in Blood for Duration of Curve x duration of curve
ESV is dependent upon the following
: a. Force of Contraction: The greater the force of contraction the more blood is ejected from the left ventricle leaving less blood in the left ventricle following ventricular contraction.
Ejection fraction in a diseased heart at rest:
< 45% (i.e. >55%: of blood remains in the heart after contraction).
ESV
= the amount of blood in the left ventricle after ventricular contraction
EDV
= the amount of blood in the left ventricle preceding ventricular contraction.
Common practice among weight lifters is to force exhalation against a
closed glottis (the glottis is the narrowestpart of the larynx through which air passes into the trachea).
There are many sports drinks available. More concentrated sports drinks can be used in
cold
Symptoms include
cold and clammy skin; light-headedness; weakness and fatigue; nausea; and a weak pulse.
This increase in intrathoracic pressure causes thoracic veins to
collapse and reduces
Without surfactant small alveoli can
collapse due to the pressure which impairs their ability to remain open.
In this way some elite endurance athletes cannot achieve
complete oxygenation of arterial blood during intense exercise. This is called exercise induced arterial hypoxemia (EIH).
As heart rate increases there is less time for the left ventricle to
completely fill with blood.
The released oxygen diffuses from the blood into the tissues down its
concentration gradient.
Powerade and All Sport have higher
concentrations of carbohydrate which slows gastric emptying.
In Dr. Noakes's view short-term dehydration isn't an illness of health threat but a
condition of human existence.
Those who are really fit tend to have a greater ability to
conserve sodium.
AVH is released when the body is dehydrated and causes the kidneys to
conserve water thereby reducing urine volume.
Because carbon dioxide is continually diffusing into the alveoli from venous blood and because oxygen is continually diffusing into the pulmonary circulation from the alveoli the composition of alveolar air is
constantly changing.
Thus some vessels of the body must always be partially
constricted in order to maintain blood flow
transition from rest to exercise which results from changes in the
constriction and dilation of
For each pound of weight loss
consume 15 fluid ounces.
The increase in stroke volume with training is primarily the result of
continual increases in ventricular filling leading to an enlarged left ventricular chamber. Training also causes a greater ability for the, left ventricle to stretch (compliance);which in turn; increases the capacity of the left ventricle to hold blood (end-diastolic volume - to be discussed in detail later).
This shift downward and to the right is referred to as the
Bohr effect and increases oxygen availability for the working muscles.
Inspiration and expiration follow
Boyle's Law which states that pressure is inversely
The most rapid rise in stroke volume occurs at the beginning of exercise because
There is an increase in activity of the SNS causing an increase in myocardial contraction (i.e. force of contraction).
2. Transport of carbon dioxide down its partial pressure gradient:
Tissues>Blood>Lungs>Atmosphere
Ventilation-Perfusion Ratio at Rest:
VE/BF= (4.2 L air/min - 6.0 L air/min)/5.0 L blood/min
This causes competition between
VO2 going to the active locomotor muscles and the respiratory muscles and can severely compromise exercise capacity.
There are three factors which aid in the speed and efficiency of blood return to the heart:
Venoconstriction, Muscle pump, Respiratory pump.
1. Tidal Volume (TV):
Volume of air moved during either the inspiratory or expiratory phase.
Those responding to the heatstroke victim should try to
cool him/her with a sponge or cold water bath; by loosening his/her clothing and by fanning while waiting for professional help.
Treatment involves
cooling the body with cold compresses or a cold bath; and frequent; but small intakes of fluids containing sodium.
By contrast exercise taking place in dry and cool environments can
exaggerate the symptoms
Even though VE increases greatly with exercise TV's rarely
exceed 60% of vital capacity.
It is important to note however that some people experience hyponatremia without
excessive drinking but for some reason sodium levels decrease.
exchange in emphysema causes
excessive ventilation even at low intensity exercise and leads quickly to ventilatory muscle fatigue.
Pulmonary ventilation is the
exchange of air between the lungs and the atmosphere.
The SNS is dominant during
exercise and has two types of fibers which play major roles in the
they are not significantly influenced by
exercise training with the exception of swimming and
Gas exchange is not considered to be a limiting
factor with respect to maximum aerobic capacity
Females have higher levels of 2;3 DPG than males of similar
fitness levels and physical activity
• A 6.7% improvement in performance with adequate intakes of
fluid during exercise compared to low intakes of fluid.
. During prolonged exercise it is almost impossible to replace
fluid equal to its loss.
Plasma is the
fluid or watery component of blood.
Ingestion of pure water causes less
fluid retention in the body when compared with a drink containing glucose and some sodium.
• A 6.3% improvement in performance when carbohydrate was added to
fluids during exercise compared to fluids without carbohydrate.
Runners experience RBC hemolysis (breakage) during
foot strike and have a higher risk of anemia
The ejection fraction is increased during exercise due to increases in norepinephrine and epinephrine which increase the
force of contraction of the ventricles and the amount of blood that can be ejected with each heart beat.
Blood is divided into two components
formed components and plasma.
carries four molecules of oxygen)
four
volume
four times
The total vascular space of the body is approximately
four times the size of the actual blood volume.
supplementing with glycerol yet also report feeling more
fresh at the end of a race.
. Sports drinks containing mostly
fructose can cause GI distress.
MVO2 is a
fundamental measure of fitness representing the capacity for aerobic energy transfer.
CO2 values can be easily obtained from a
gas analyzer and are substituted in the Fick Equation.
V-aCO2 difference is estimated with the
gas analyzer with several accepted assumptions.
VO2 is measured with a
gas analyzer.
Values for O2 consumption can simply be obtained with a
gas analyzer.
Thus less oxygen is reaching the alveoli for
gas exchange in untrained individuals.
. This inappropriate response can be
genetic and exacerbated by medications including NSAIDs; which many marathoners take to relieve pain and inflammation.
The best sports drinks are made from
glucose or glucose polymers which are also referred to as
The partial pressure of a gas is equal to the
percent concentration of the gas multiplied by the total pressure of the gas mixture.
The ejection fraction provides an indication of the
percentage of blood pumped out of the heart.
Athletes who have hematocrit levels greater than 50% are suspected of using
performance enhancing drugs such as erythropoietin (EPO) or participating in the illegal act of blood doping.
Partial pressure is denoted by
placing a 'P' in front of a gas.
Aerobic training increases the number of RBC's but also increases
plasma volume.
Much of fluid replacement is achieved during the
post-exercise recovery period.
Measurements of lung function are primarily used to identify the
presence and extent of lung
Too much salt however
prevents rehydration.
The trachea branches into two bronchi which provide the
primary pathway for oxygen
Recovery sports drinks like Endurox contain more
protein which is necessary during the
Some sports drinks like Accelerade include a small amount of
protein.
Fluid with an osmolality that is less then blood osmolality will cause water to be
pulled from the GI tract to the blood. This leads to water absorption.
During intense exercise alveolar ventilation rises disproportionately to
pulmonary blood flow such that the ventilation-perfusion ratio may exceed 5.0 L air/min., which still provides a uniform pulmonary blood flow distribution for adequate oxygenation of venous blood.
Alveoli are surrounded by
pulmonary capillaries where gas exchange takes place.
Large ventilation-perfusion ratios waste
pulmonary ventilation by overventilating alveoli that can't use all the oxygen while providing inadequate oxygen for alveoliin need.
Fatigue from strenuous activity is associated with feeling "out of breath" but
pulmonary ventilation is not a limiting factor of aerobic performance.
Blood flow to the muscles during exercise is critical fo
r oxygen and nutrient delivery to the working muscles.
The rate of blood flow to the respiratory muscles during maximum exercise can equal the
rate of blood flow going to the active locomotor muscles.
Gatorade promotes a faster
rate of fluid absorption into the bloodstream relative to Powerade and
which forces the
reactions occurring at the tissue level to reverse so that carbon dioxide is
There are approximately 280 million hemoglobin for each
red blood cell and approximately 25 trillion red blood cells pass through our circulatory systems.
(Cl-) moves from the plasma to the
red blood cell in order to maintain ionic equilibrium or
Thus
red blood cells are not adequately, replaced after they die.
Hemoglobin is the main component of
red blood cells.
Neural and local control are the primary sources of control for
redistributing blood flow during the transition from rest to exercise with the hormonal influence only serving a minor role.
This may not be related with a decrease in cardiac output but rather a
redistribution of blood flow and oxygen delivery within and between the exercising muscles.
Chronic endurance training counteracts the
reduction in SV during high workloads and heart rates.
Loss of fluid and electrolytes (mainly sodium) causes a
reduction in blood volume; a reduction in blood flow to the skin; a decrease in sweat rate and cooling, and a rise in body temperature.
Pure water ingestion with a meal will result in
rehydration.
Because a true mVO2 value is very hard to obtain
the highest value of oxygen uptake obtained during the test (peak VO2) is frequently used in place of mVO2.
The partial pressure of dissolved carbon dioxide (PCO2) regulates
the loading and unloading of
Having some air remain in the lungs following maximum exhalation is important to prevent
the lungs from collapsing and for continual gas exchange between the alveoli and blood.
Redistribution of blood flow refers to an overperfusion of glycolytic fibers and an underperfusion of oxidative fibers that are doing
the majority of the work.
The factors contributing to the cardiac output (heart rate and stroke volume) differ between
trained and untrained individuals.
Stroke volume is greater in
trained individuals at rest and during exercise relative to untrained individuals.
Resting heart rate is lower in
trained relative to untrained individuals
Approximately 20% of carbon dioxide is
transported with hemoglobin: CO2 + Hb>HbCO2
For instance no differences are observed in vital capacity between
endurance-trained
This provides the individual with the feeling of having more
energy.
Ma Huang is the plant source of
ephedra.
From much research on hyponatremia Timothy Noakes (a noted South African sports-medicine physician) wrote an
"Advisory Statement on Fluid Replacement During Marathon Running" for the International Marathon Medical Directors Association.
Sip on fluids frequently
(1/2 cup every 10 minutes) until exercise begins.
Decrease in oxygen extraction
(diffusion capacity for oxygen is decreased).
approximately
.3 ml (2%) of oxygen is dissolved in the blood which is necessary for the purposes
Carbon dioxide
0.03% and 0.2 partial pressure
A normal ventilation-perfusion ratio ranges from
0.84 to 1.2 at rest.
three different ways (Figure 13.7):
1. Approximately 7% to 10% of carbon dioxide produced in the tissues is dissolved in the plasma (establishes the partial pressure of carbon dioxide in the blood).
by:
1. Closure of small peripheral airways 2. Accumulation of pulmonary extravascular fluid
Oxygen is transported in the blood in two ways:
1. Dissolved in plasma (i.e. blood consists of plasma (fluid portion of blood) and red blood cells).2. Transported with hemoglobin.
it
1. Regulates breathing. 2. Regulates the loading and unloading of hemoglobin.
Myoglobin has two purposes:
1. To store a small amount of oxygen in muscle cells. 2. To transport oxygen from the cell membrane to the mitochondria.
Other recommendations include:
1.) Don't drink obsessively in the several days before a marathon. Drink when you are thirsty; 2.) Don't take NSAIDs such as aspirin; ibuprofen; or naproxen sodium before; during; or immediately after your race; 3.) Weigh yourself before and after the marathon; 4.) During the marathon; drink when you are thirsty: 5.) Drink less if you begin to get a queasy; sloshy feeling in your stomach; 6.) Drink a sports drink rather than water. But don't expect sport drinks to prevent hyponatremia; and 7.) Don't chug fluids immediately after the marathon because this is a time when the risk of hyponatremia can be quite high as stomach fluids are absorbed into the bloodstream. Nibble on solid foods and sip a variety of drinks slowly until you feel well recovered.
The Consensus gives you two hydration options:
1.) Drink according to thirst or 2.) Weigh yourself before and after a workout to determine your unique sweat rate per hour.
Each gram of hemoglobin can combine with
1.34 ml of oxygen.
Body temperature can rise as quickly as
1.8 degrees Fahrenheit every 5 to 7 minutes as fluid is
Sports drinks are equivalent to
1/5th saline solution.
Glucose polymers provide
10 times more energy than simple sugars but don't delay the rate of gastric emptying.
During exercise stroke volume is approximately
10-15 ml/b higher in the supine position relative to the upright position
There is a ____% drop in peak VO2 each decade
10.
Partial Pressure of oxygen (PO2) in blood at rest:
100
Partial pressure of oxygen in blood during exercise
100
Trained Stroke Volume at rest
100
Both the dissolved oxygen and the oxygen bound to hemoglobin exert a partial pressure of
100 mm Hg.
Death will occur when body temperature reaches
110 degrees Fahrenheit.
At maximum exercise untrained Stroke Volume is
113 ml/b
6. Functional Residual Capacity (FRC):
Amount of air left in the lungs after a normal exhalation
5. Residual Volume:
Amount of air remaining in the lungs following a maximum exhalation.
MVV in Obstructive Lung Disease:
Approximately 40% or less of MVV values in a healthy lung.
Aortic Pressure (afterload):
As aortic pressure increases; less blood can be ejected into the aorta from the left ventricle leaving more blood in the left ventricle following ventricular contraction.
1. Transport of oxygen down its partial pressure gradient:
Atmosphere>Lungs>Blood>Tissues
VO2 is dependent upon
CO (HR x SV) and a-vO2 difference.
The Fick Equation:
CO = O2 Consumption (ml/min) / a-vO2 Difference (ml/100 ml blood)
The Fick Equation is a direct measurement of
CO.
H2CO3 =
Carbonic Acid
Rest:
Diaphragm contracts > chest cavity expands > lung volume increases > lung
Exercise:
Diaphragm contracts > chest cavity expands > lung volume increases > lung pressure
SV =
EDV - ESV
Ejection Fraction =
EDV - ESV/ EDV or SV/EDV
Stroke volume (SV) is dependent upon
EDV; ESV; and body position.
In turn the reduction in venous blood flow reduces
EDV; stroke volume;and arterial blood pressure below normal causing a reduction in blood flow to the brain and consequent dizziness and fainting. When the Valsalva Maneuver is stopped and the glottis reopens, intrathoracic pressure normalizes and blood flow overshoots causing an increase in arterial blood pressure (Figure 12.10a, b, and c).
VO2 =
HR x SV x a-vO2 difference
This helps to compensate for the lower
Hb levels experienced in females relative to males.
Cardiac Output:
Heart Rate x Stroke Volume
___ is lower in trained individuals relative to untrained individuals at the same workload
Heart rate.
No relationship exists between
MVO2 and MVV or FVC.
In addition exercise can improve
MVV and pulmonary function in individuals with lung disease.
3. Expiratory Reserve Volume (ERV):
Maximum exhalation beyond TV.
2. Inspiratory Reserve Volume (IRV):
Maximum inhalation above TV.
MVV in a Normal Healthy Lung:
Men: 140 L/min to 180 L/min ; Women: 80 L/min to 120 L/min
2. Muscle Pump:
Muscle contractions of active muscle allow the muscle to expand in all directions.
Ischemia
Oxygen supply to the heart does not match oxygen demand of the heart.
In the trained individual the ________ has a greater influence on the SA node resulting in a lower heart rate
PNS
The loss of dissolved oxygen in the bloodstream lowers the
PO2 in the
A high VO2 max requires an integrated and high-level response of several physiological systems working together to support the oxygen transport system:
Pulmonary ventilation ;Hemoglobin concentration; Blood volume and cardiac output ;Peripheral blood flow ; Aerobic metabolism
(i.e.
RV + ERV).
There are several reasons for the drop in peak mVO2:
Reduction in capillary density causing a decrease in the number of red blood cells that lie next to the muscle fibers and therefore a reduction in oxygen delivery and uptake into the working muscle (i.e. decrease in diffusion capacity and oxygen delivery).Reduction in the rate of change from vasoconstriction to vasodilation in the working muscles during exercise.
There are several reasons for the drop in peak mVO2:
Reduction in or redistribution of microvascular blood flow (this is considered to be a bigger factor for reducing peak mVO2 than a decrease in oxygen extraction). Redistribution of blood flow refers to an overperfusion of glycolytic fibers and an underperfusion of oxidative fibers that are doing the majority of the work Decrease in cardiac output.
There are several reasons for the drop in peak mVO2:
Reduction in pulmonary uptake of oxygen.
Moderate and Intense Exercise:
Relaxation of inspiratory muscles (diaphragm) and passive
2. Expiration:
Rest and Light Exercise: Relaxation of inspiratory muscles (diaphragm) and passive recoil of the stretched lung > chest cavity decreases > lung volume decreases lung pressure increases above atmospheric pressure > expiration
1. Venoconstriction:
SNS stimulation causes venoconstriction (constriction of veins) to increase
The larger cardiac output in trained individuals results from larger _______ relative to untrained individuals at the same workload
Stroke volume.
What is higher in trained individuals because exercise training strengthens the heart muscle (ventricle muscles) which allows the ventricles to eject more blood with each ventricular contraction
Stroke volume.
4. Forced Vital Capacity:
TV + IRV + ERV
Ventilation is equal to the
TV multiplied by the breathing rate.
Cardiac output (CO) can be determined by three different methods
The Fick equation ; Indicator Dilution method; Carbon dioxide(Co2) rebreathing method.
Venous Return:
The greater the amount of blood returning to the left ventricle; the greater the EDV and SV.
Chamber Size of Left Ventricle:
The greater the chamber size; the more room for blood filling in the left ventricle and the greater the EDV and SV.
Force of Contraction:
The greater the force of contraction the more blood is ejected from the left ventricle leaving less blood in the left ventricle following ventricular contraction.
3. Respiratory Pump:
There is a decrease in intrathoracic pressure and an increase in intra-
blood flow through the vessels which allows for
a greater cardiac output and oxygen delivery to the tissues.
The following explanations are provided for the cause of arterial desaturation:
a. Mismatching of the ventilation-perfusion ratio within the lungs or specific lung regions ; b. Shunting of blood between venous and arterial circulations such that the diffusion area is bypassed; c. Failure to achieve end-capillary equilibrium between alveolar oxygen pressure and pressure of oxygen in blood perfusing the pulmonary capillaries
The most rapid rise in stroke volume occurs at the beginning of exercise because:
a. There is an increase in muscle contraction which puts pressure on the veins to pump blood back to the heart (i.e., increase in venous return).
exchange resulting from:
a. Underperfusion of blood (pulmonary blood clot or pulmonary hemorrhage).b. Inadequate ventilation relative to the size of the alveoli (emphysema; asthma; pulmonary fibrosis).
EDV is dependent upon the following:
a. Venous Return
2. Cholinergic fibers from the SNS release
acetylcholine to cause dilation in vessels travelling to
The expiratory muscles stabilize the
abdominal and chest cavities during heavy lifting.
This is referred to as the Valsalva Maneuver and stabilizes the
abdominal and thoracic cavities to enhance muscle action.
Because a pressure gradient is established between the abdominal area and the thoracic area during inspiration and expiration blood moves from the
abdominal area to the thoracic area during inspiration and from the intrathoracic area to the abdominal area during expiration.
These differences limit expiratory flow and cause greater respiratory muscle work for highly trained women compared to trained men and impairs the
ability for highly trained women to maintain consistent oxygen exchange between the alveoli and pulmonary capillaries.
training improves the
ability to sustain high levels of submaximum ventilation by increasing the
Plasma volume can increase 10% at rest as an adaptation to aerobic training and/or
acclimatization to hot and humid weather in trained athletes.
by the
alveolar epithelial cells and reduces the surface tension between the alveolar membrane and surrounding tissues.
The ventilation-perfusion ratio is the ratio between
alveolar ventilation and pulmonary blood flow. See Figure 12.8
Blood flow through the lung is greatest at its base such that pulmonary blood flow exceeds
alveolar ventilation and the ventilation-perfusion ratio is less than 1.0 (either due to overperfusion or underventilation).
A ventilation-perfusion ratio of 0.84 (4.2/5.0) means that
alveolar ventilation of 0.84 L matches each liter of pulmonary blood flow.
In those with pulmonary disease and in some cases in highly trained endurance athletes who are participating in high intensity exercise the mismatching of
alveolar ventilation with pulmonary blood flow causes gas exchange problems.
At the lungs the dissolved carbon dioxide diffuses from the venous blood into the
alveoli down
The released carbon dioxide diffuses from the venous blood into the
alveoli down its partial pressure gradient and is expired. H+ + HCO3- > H2CO3> CO2 + H20HbCO2 >CO2 + Hb
This makes it easier for the
alveoli to inflate and deflate.
The 17th to the 23rd generations of bronchioles contain
alveoli.
Residual volume is the
amount of air left in the lungs following maximum exhalation.
Stroke volume is defined as the
amount of blood pumped out of the heart each beat.
Inspired air which does not reach the 17th generation of bronchioles becomes trapped in the
anatomical dead space and does not participate in gas exchange.
A portion of each breath is trapped in the
anatomical dead space.
Normal hemoglobin levels are between 14 mg/dL to 18 mg/dL for men
and between, 12 mg/dL to 16
humidify
and filter air to protect the alveoli from damage.
absolute workload
and therefore, are less likely to ventilate the dead space.
Yohimbe interacts with
antidepressants.
The movement of the lungs is synonymous with the movement of the chest wall so that
any change
The ventilation-perfusion ratio exceeds 1.0 at the
apex at the lung as alveolar ventilation is greater than pulmonary blood flow (either due to underperfusion or overventilation).
Those who experience hyponatremia have high levels of
arginine vasopressin (AVP) (also known as antidiuretic hormone (ADH)).
adequately loaded with oxygen (i.e.
at a PO2 of 60, hemoglobin only loses 8% of its saturation
Any reduction in blood flow to the muscles will compromise
athletic performance.
Other studies have shown that sports drink don't prevent hyponatremia but can
attenuate hyponatremia.
however requiring cardiac catheterization to obtain an accurate measurement of the
average oxygen content of all venous blood (i.e., each individual vein only reflects the metabolic activity of the tissue it drains)(Figure 17.1).
2. Exercise: Breathing rate and TV
increase.
Platelets aid in blood clotting which prevents
blood loss from a wound.
Ideal osmolality in sports drinks should fall within the range of
blood osmolality.
The increase in blood volume in the left ventricle (end-diastolic volume) allows
more blood to be pumped out of the left ventricle with each beat.
In addition the one -way valves present in large veins prevent
backflow of blood in the venous system when the muscles relax.
Iron makes up the heme portion of hemoglobin where oxygen
binds and folic acid is involved in
The muscle pump plays a major role in moving
blood back to the heart (See Muscle Pump and Venous Return Figure).
Some vessels of the body must always be partially constricted in order to maintain
blood flow and blood pressure in the body. The distribution of blood flow changes dramatically during the transition from, rest to exercise which results from changes in the constriction and dilation of vessels at the arteriole level traveling to the tissues of the body.
Because dehydration results in a decrease in blood volume due to the loss of sodium (sodium acts to maintain blood volume)
blood flow to the muscles and other tissues is impaired.
The technique requires no
blood sampling and is noninvasive.
Alveoli have the largest
blood supply of any organ in the body.
High intakes of glycerol may cause
blurred vision and headaches.
The increase in residual volume following exercise alter the determination of
body density with
Heatstroke can cause death and is characterized by a high
body temperature (above 105 degrees Fahrenheit); hot and dry skin; fluctuating consciousness; and a rapid pulse.
Fluid loss can be monitored by changes in
body weight.
Heat exhaustion occurs when blood flow to the
brain is reduced.
Techniques which are used to measure residual volume involve
breathing in a tracer gas such as helium; neon; or nitrogen.
In those with exercise-induced asthma however bronchospasm and bronchoconstriction follow
bronchodilation causing chest tightness; wheezing; coughing; and shortness of breath which can last as long as 90 minutes.
In the heaviest smokers 14% of the total VO2 went to the respiratory muscles immediately after smoking
but only 9% of the total VO2 went to the respiratory muscles after a day of abstinence from cigarette smoking.
The increased resistance will not compromise ventilation at rest or light activity
but would impair performance during intense exercise.
The exchange of a HCO3- for a chloride ion is called the
chloride shift.
o Consume enough fluid before exercise so that urine is a
clear color: consume about ½ liter of
Improvements in SV represent a
central response to training. Improvements in avO2 difference represent a, peripheral response to training.
o Avoid large amounts of
caffeine which can promote fluid loss.
At the tissue carbon dioxide binds to hemoglobin forming
carbaminohemoglobin.
• A 12.4% improvement in performance when
carbohydrate was added to fluids during exercise compared to low intakes of fluid without added carbohydrate.
Glycerol is a 3-carbon molecule that is metabolized like a
carbohydrate yielding 19 Kcal/g. Because glycerol attracts wate, it retains ,fluid in the body and it aids in superhydration for the
Gas exchange between the alveoli and pulmonary circulation involve the transfer of inspired oxygen across the respiratory membrane from the alveoli into venous blood and the transfer of
carbon dioxide across the respiratory membrane from the venous blood into the alveoli for expiration into atmospheric air.
When the partial pressure of carbon dioxide (PCO2) is high in venous blood
carbon dioxide and
Each gas in atmospheric air (oxygen
carbon dioxide, and nitrogen) exerts, a partial pressure.
During exercise _____ is substantially higher in trained individuals relative to untrained individuals during exercise at the same workload
cardiac output.
Decrease in
cardiac output.
For endurance athletes the pulmonary system may not be as efficient as the
cardiovascular and
Further glycerol supplementation is not recommended for those with compromised
cardiovascular systems because of the unknown stress of the water retention on the cardiovascular system.
When hemoglobin is fully saturated with oxygen 20 ml of oxygen is
carried with hemoglobin for each 100 ml of blood.
The majority of this water is removed from
cells and interstitial spaces of the body
Glucose polymers are derived from the partial breakdown of
corn starch and consist of several glucose molecules linked together.
Platelets also contribute to the formation of blood clots in the
coronary arteries or carotid arteries leading to a heart attack or stroke.
Surface tension occurs when a resistive force is
created at the surface of a liquid in contact with
intrathoracic and intrabdominal pressures increase by
more than 150 mm Hg above atmospheric
Venoconstriction plays a minor role in
moving blood back to the heart.
as fenprometamina; phenpromethamine; phenpromethaminum; phenylpropylmethylamine; and benzedrine) are stimulants often added to
energy drinks that are prohibited by WADA.
Blood flow and oxygen/nutrient delivery to the muscles is critical for
efficient muscular work and performance.
Sports drinks contain
electrolytes and carbohydrates.
There is a 10% drop in peak VO2 each
decade.
progressively
decrease and residual lung volume progressively increase.
MVO2 may be reduced as a result of
decreased oxygen delivery to the working muscles.
Because plasma volume increases to a greater extent than the number of RBC's hematocrit actually
decreases a bit with aerobic training.
The volume of gas ventilated for 15 seconds is converted to the volume of gas ventilated if the subject had continued fast
deep breathing for one minute (i.e., MVV is the volume of gas ventilated for one minute , determined from 15 seconds of fast, deep breathing).
It is important that physicians and nurses recognize that collapsed athletes are not necessarily
dehydrated. They may actually be hyponatremic.
In this regard heart rate immediately increases at the onset of strenuous activity but there is a
delay or lag in coronary blood flow necessary to meet the elevated demands of the heart. Coronary blood flow is delayed because there is not enough time for, thevasodilators to override the vasoconstrictors in the coronary vessels.
Ischemia can be identified on the EKG as a
depressed ST segment and is frequently accompanied by chest pain.
Partial pressure and solubility are important factors in
determining the rate of gas exchange.
Stroke volume is equal to the
difference between end-diastolic volume (EDV) and end-systolic volume (ESV):
Sports drinks and energy drinks are very
different.
Obtaining values for the a-vO2 difference is
difficult and invasive
During exercise 75% to 85% is released from hemoglobin to
diffuse into the tissues (i.e., a-vO2
At rest only 25% of oxygen is released from hemoglobin to
diffuse into the tissues.
The larger the diffusion gradient the faster the
diffusion rate of carbon dioxide from the muscle
The larger the diffusion gradient the faster the
diffusion rate of oxygen from the blood into the muscle cells.
Surfactant mixes with the fluid that surrounds the alveolar chambers and
disrupts the water layer
Carbonic acid quickly
dissociates into a proton and bicarbonate.
Because DNA synthesis is slowed and the ability of RBC's to divide are compromised with folic acid deficiency large oval shaped and immature RBC's are formed which
do not carry oxygen or pass through the capillary bed as efficiently as normal RBC's.
Training improves the ________ of the heart so that more blood is pumped out of the heart with each beat and the heart does not have to work as hard at rest when compared to an untrained individual
efficiency
Those experiencing heat stroke need to
go the hospital for treatment.
The ventilation-perfusion ratio varies depending on the region of the lung due to
gravitational
Because chloride moves into the red blood cell in exchange for a bicarbonate moving out of the red blood cell venous red blood cells contain a
greater amount of chloride than arterial red blood cells.
The top of the lung lies above the
heart and the base of the lung lies below the heart.
Heat stroke is caused by a decrease in
heat dissipation due to humidity; excessive clothing;
The percentage of RBC's to the total blood is referred to as
hematocrit.
Hemoglobin has___ iron atoms each of which can combine with oxygen (i.e.
hemoglobin
At a PO2 of 100 mm Hg
hemoglobin is 98% saturated with oxygen in the pulmonary
3. In the blood dissolved oxygen and oxygen bound to
hemoglobin travel to the tissues (cells).
Individuals with some lung diseases and those who live at altitude have
higher levels of 2;3 DPG
Heat cramps can also occur during training and racing in
hot and humid environments without proper acclimatization.
MVO2 is higher during maximum exercise using the legs relative to the arms due to the larger musculature of the legs. During submaximum exercise
however, VO2 is lower in the legs than the arms at the same given power output due to less mechanical efficiency in the upper body and the need for the upper body to recruit additional muscles to stabilize the torso during upper body exercise (Figure 17.6).
Fluid that has an osmolality that exceeds blood osmolality is called
hypertonic and pulls water from the blood into the GI tract cells to dilute the concentrated fluid. This leads to temporary dehydration.
Emergency rooms in cities where endurance events are held should be educated about
hyponatremia and its treatment.
Because of their smaller size; women are at greater risk for
hyponatremia than men.
Consuming sports drinks does not necessarily protect you from
hyponatremia.
Low sodium levels in the body's cells leads to
hyponatremia.
Several studies have indicated that many marathoners and Ironman triathletes are
hyponatremic while competing.
In another study 63 out of 488 finishers in the Boston Marathon were found to be
hyponatremic. Four women marathoners have died from ,hyponatremia.
Heat cramps occur with a fluid and electrolyte
imbalance resulting from dehydration. Athletes who experience heat cramps tend to be heavy sweaters and lose large amounts of electrolytes; particularly sodium; in their sweat.
The iron supplementation group significantly
improved exercise performance compared to the
lead to an increase in EDV which in turn
increases SV and allows heart rate to be lowered to
Increases in mVO2 with training result from
increases in SV and a-vO2 difference.
The greater blood volume from both the increase in RBC's and plasma volume allow a greater cardiac output in those who are trained which
increases the amount of oxygen being delivered to the working muscles.
By reducing surface tension surfactant allows the alveoli to
inflate and deflate more easily.
Acidity; temperature; and carbon dioxide levels do not
influence the
Voluntary muscles control
inspiration and expiration.
During exercise constriction of vessels going to less active tissues (internal organs) and dilation of vessels going to active tissues divert blood flow from the
internal organs to more active tissues.
Iron deficient subjects received
intramuscular iron supplementation or intramuscular placebo for 80 days.
Myoglobin has one
iron atom which can bind to one oxygen molecule.
Residual volume is frequently estimated from
known vital capacities (obtained with a spirometer) or from calculations involving age and gender.
Although thirst isn't a good indicator of hydration it is dangerous to override the
lack of thirst and drink too much.
Heat cramps are
muscle spasms in the legs and abdomen caused by severe dehydration.
The lungs have a very
large surface area for gas exchange.
The myoglobin curve can be depicted as a
left shift in the oxyhemoglobin dissociation curve. During rest and moderate exercise myoglobin holds onto its, bound oxygen (i.e., at a PO2 of 40 mm Hg, myoglobin is still 95% saturated with oxygen).
A decrease in temperature shifts the oxyhemoglobin curve to the
left which keeps oxygen bound to hemoglobin at lower PO2's resulting in a higher percentage of oxygen saturation at any given PO2.
(emphysema) and are
limited in their ability to receive adequate oxygen delivery from the
Thus the respiratory system is not the
limiting factor during exercise and is not maximally stressed during maximum exercise.
This linkage lowers the osmolality of the fluid compared with individual glucose molecules that are not
linked together .
1. The partial pressure of dissolved oxygen (PO2) regulates the
loading and unloading of
Hyponatremia:
loss of sodium
Hypernatremia:
loss of water
Although acute blood loss from an accident or donation of blood can cause anemia the most common causes of anemia result from
low iron and folic acid levels in the body.
Anemia is caused by
low levels of hemoglobin which reduces the amount of oxygen that can be
When standing at rest the force of gravity pulls blood into the
lower extremities and reduces stroke volume.
This recommendation is almost 50%
lower than previous recommendations.
Adult women have a reduced
lung size; smaller lung volumes; reduced airway diameters; and a smaller diffusion surface than men even after adjusting for differences in height.
Genetics are primarily responsible for the larger-than-normal
lung volumes observed in some athletes.
The increase in SV means the heart doesn't have to work as hard (beat as much) in order to
maintain cardiac output.
During light exercise the ventilation-perfusion ratio is
maintained.
In order for adequate gas exchange to take place the ventilation of the alveoli must be
matched
MVV is 25% higher than the volume of gas ventilated during
maximum exercise.
Residual volume cannot be
measured with a spirometer.
Tyrosine and phenylalanine are amino acids which can interact with
medications.
cells and the
membrane of the pulmonary capillaries.
Geranium is also called
methylhexaneamine and is prohibited by the World Anti-Doping Agency
Reduction in or redistribution of
microvascular blood flow (this is considered to be a bigger factor for reducing peak mVO2 than a decrease in oxygen extraction).
warm-up is associated with a
mismatching in coronary blood flow (oxygen supply) and heart rate
Oxygen has a larger partial pressure gradient than carbon dioxide yet carbon dioxide is
more
Those who are physically fit sweat
more and sweat earlier in exercise relative to those who are
For serious stage 3 hyponatremia (life threatening symptoms) oxygen and a hypotonic solution
must be administered (solution that forces water to be secreted through the kidney while retaining sodium by the body).
EDV (preload): As EDV increases the ventricles are filled with more blood which increases the stretch on the
myocardial fibers leading to an increase in the force of contraction and SV and a reduction in blood remaining in the left ventricle following contraction.
Ischemia typically precedes
myocardial infarction.
Athletes experiencing hyponatremia have symptoms of
nausea; vomiting; headache; puffiness; muscle cramping; and confusion.
Redistribution of blood flow is dependent upon
neural hormonal and local control.
1. Adrenergic fibers from the SNS release
norepinephrine to cause constriction in vessels
maintain
normal acidity (pH) within the red blood cell.
*Male and female athletes exceed values observed in
normal healthy lungs.
When a warm-up preceded the same strenuous exercise however ischemia was
not observed in any of the firemen.
Because nitrogen is not utilized or produced during metabolic reactions of the cells its concentration is
not significantly altered during the different phases of gas exchange.
Exercise taking place in humid environments limit the severity and in some individuals
obliviate exercise-induced asthma.
One study showed that those who consumed sports drinks did not have a lower risk for developing hyponatremia than those who consumed
only water - the reason being that sports drinks are primarily water themselves and contain only small amounts of sodium.
Research indicates that hyponatremia is caused by two concurrent events:
overdrinking and an inappropriate hormone response that limits normal urination
Heatstroke can occur in athletes who
overexert themselves in hot and humid environments.
Hyponatremia is caused by
overhydration while exercising.
Like skeletal and cardiac muscle there is an increase in the
oxidative capacity of the respiratory
a. VO2 fails to increase with increasing workload (i.e.
oxygen consumption levels off as workload continues to increase)(See Figure 7.4). b. RER = 1.15
*The reductions in heart rate in the iron supplementated group increased
oxygen delivery to the
Even during exercise when the rate of blood flowing through the pulmonary capillaries increases blood cells continue to be adequately loaded with
oxygen due to the rapid diffusion of gases between the alveoli and the blood.
Shallow breathing causes air to be trapped in the anatomical dead space and prevents
oxygen from reaching the alveoli where gas exchange between the alveoli and pulmonary capillaries takes place.
In turn this impairment in oxygen exchange compromises
oxygen saturation in the arterial blood and aerobic capacity in highly trained women compared with men.
The redistribution of blood flow during exercise is necessary to bring needed
oxygen to the working muscles while maintaining blood pressure throughout the body's vascular network.
Like other muscles the respiratory muscles require
oxygen.
For instance PO2 is the
partial pressure of oxygen.
The partial pressure values represent average values for the
partial pressures of oxygen; carbon dioxide; and nitrogen.
Plasma volume can decrease 10% during high-intensity physical activity
particularly if the
Athletes have significantly higher breathing rates and TV's
relative trained exercising individuals.
Thus carbon dioxide and oxygen diffuse
relatively at the same rate.
Norepinephrine and epinephrine released during exercise serve to
relax the smooth muscles of the pulmonary arteries.
Stimulants allow stored glucose to be
released very quickly and abundantly.
Those with chronic obstructive pulmonary disease (COPD) experience an increased
resistance to
Up to 15% of the total VO2 can go to the
respiratory muscles during maximum exercise.
AVP is a hormone that regulates the body's
retention of water and acts to increase water reabsorption in the kidneys.
This alteration is transient however and hemoglobin and hematocrit levels will
return to normal within a few weeks.
The temperature of muscles increase with exercise which shifts the oxyhemoglobin dissociation curve shifts to the
right and forces bound oxygen to be released from hemoglobin making oxygen available or the active muscles
the
right because H+ binds to hemoglobin which reduces the affinity that hemoglobin has for oxygen at higher PO2's
The binding of H+ with hemoglobin at the tissue level reduces hemoglobin's affinity for oxygen shifting the oxyhemoglobin dissociation curve to the
right so that oxygen is released from hemoglobin and available for the tissues.
2. The flat portion of the oxyhemoglobin curve represents a
safety zone in that even at lower
For heavy sweaters additional
salt can be added to the sports drink (1/2 teaspoon) or an electrolyte tablet (50-300 mg sodium/tablet).
are easily
saturated with oxygen.
decreases below atmospheric pressure > inspiration and Contraction of the muscles between the ribs (external intercostals
scalene muscles, and pectoralis major) > ribs rotate and lift >^ expansion of chest cavity > ^ lung volume > decrease in lung pressure >greater inspiration relative to rest
The bronchi divide into
several bronchioles (23 generations)
The increase in acidity; temperature; and carbon dioxide production accompanying exercise causes the dissociation curve to
shift downward and to the right so that more oxygen is released from hemoglobin at a higher PO2.
Some studies report higher levels of 2;3 DPG in endurance athletes particularly during
short duration maximal efforts compared with untrained subjects.
During the beginning stages of an aerobic exercise program the lifespan of RBC's is
shortened and plasma volume increases which lowers hemoglobin and hematocrit levels.
Myoglobin is found in
skeletal and cardiac muscle.
Myoglobin is higher in
slow twitch muscle fibers than fast twitch muscle fibers.
The sodium aids in glucose absorption assists in the absorption of water from the
small intestine and helps to maintain blood volume and prevents excess fluid loss in the urine.
Pores of Kohn are
small pores within each alveolus which allow communication and gas exchange between individual alveoli.
Inhalers known as bronchodilator medication relax the
smooth muscles of the respiratory passages
Unflavored glucose polymers have no taste
so they provide, energy without additional sweetness. By contrast the osmolality of fruit juice is high which reduces the rate of, gastric emptying and can
environments (8%) and more diluted sports drink can be used in hot/humid environments (6%). Sports drinks have varying amounts of
sodium and potassium.
Over hydration dilutes the
sodium level in your body and causes the cells to fill up with too much water.This can lead to, brain swelling; seizures; cardiorespiratory arrest; coma and other life threatening complications.
also contribute to heat cramps; but
sodium loss usually is the main cause for heat cramps.
If cramping continues with consumption of regular sports drinks a
sodium-enriched sports drink is recommended (like Endurance Gatorade).
Those who experiencing cramping during exercise should choose a sports drink with a higher concentration of
sodium.
Several electrolytes are also lost in sweat including
sodium; potassium; calcium; magnesium; and chloride.
There is very little oxygen dissolved in the blood because it's not very
soluble in fluids.
Lung volumes are measured with a
spirometer (except residual lung volume) and vary with age;
As the muscle expands compression is applied to the veins there by
squeezing the veins to
The technique is limited in that values for CO can only be estimated during
steady state submaximum exercise (i.e.cannot estimate CO during maximum exercise; progressive exercise; or during the transition from rest to exercise).
Energy drinks contain
stimulants.
Specific respiratory exercises can improve
strength and endurance in the respiratory system and
During exercise in the supine position the flow of blood back to the heart is already close to optimal so there are only slight increases in
stroke volume when transitioning from rest to exercise in the supine position.
Maltodextrin is less sweet than
sucrose and fructose
Carbohydrate sources also vary from a mixture of
sucrose; glucose; maltodextrin; dextrose; fructose; and high-fructose corn syrup.
At rest stroke volume is highest in the
supine position because the horizontal position maximizes the flow of blood back to the heart.
Alveoli are thin walled membranous sacs which provide the
surface area for gas exchange between the lungs and pulmonary circulation.
Two to three liters of water can be lost through
sweat each hour when exercising in hot or
Because women have lower body weight and more fat women
sweat less than men when
hemoglobin travel to
the alveoli (pulmonary circulation).
venous return;
the amount of blood received by the left ventricle and stroke volume.
The larger the partial pressure difference
the faster the rate of diffusion.
The more soluble a gas is
the faster the rate of diffusion.
Compliance (stretchability) of the Left Ventricle: The greater the ability for the myocardial fibers in the left ventricle to stretch;
the more room for blood filling in the left ventricle and the greater the EDV and SV
The greater the chamber size
the more room for blood filling in the left ventricle and the greater the EDV and SV.
By lowering the total pressure of the dry inspired air to 713 mm Hg
the partial pressure
Reduction in muscle utilization of oxygen which reduces
the rate of ATP production in older adults.
In addition to being vesicles through which air moves
the respiratory passages also warm,
At rest Cardiac output is
the same for trained and untrained individuals at rest.
In addition because the carbohydrate source in Powerade and All Sport is primarily fructos
there is a greater likeliness of, GI distress.
Reduction in capillary density causing a decrease in the number of red blood cells that lie next to the muscle fibers and
therefore a reduction in oxygen delivery and uptake into the working muscle (i. decrease in diffusion capacity and oxygen delivery). Reduction in the rate of change from vasoconstriction to ,vasodilation in the working muscles during exercise.
Regular aerobic training can prevent
these alterations in lung volumes.
Because carbon dioxide binds to the globin portion of hemoglobin and oxygen binds to the heme portion of hemoglobin
they don't compete for transport in the blood.
o Consume fluids before feeling
thirsty: consume fluids every 10 minutes during exercise.
Trained individuals have higher
tidal volumes (amount of air ventilated during either the
Carbon dioxide concentration is at its highest at the
tissue level where carbon dioxide is
At tissue level the dissolved oxygen diffuses from the blood into the
tissues down its
In order to avoid hematocrit levels exceeding 50% in athletes using EPO athletes will also take blood thinners in order
to increase their plasma levels to mask the increase in RBC's.
Sports drinks cannot add more sodium because research shows that
too much sodium impedes hydration.
The sum of the partial pressures of each gas is equal to the
total pressure.
Ventilation involves the transport of inspired air from the atmosphere to the
trachea; bronchi; bronchioles; and alveoli.
During maximum exercise (i.e.
trained and untrained are not at the same workload) heart rate is relatively the same between trained and untrained individuals but trained individuals have much larger stroke volumes causing cardiac output to be much, greater.
Competitive swimmers and divers however frequently have higher
values for vital capacity relative to untrained individuals due to the resistance of the weight of water against the thorax which is believed to strengthen the inspiratory muscles (See Table 1).
The changes in intrathoracic pressure during inspiration and exhalation increases
venous return.
Short and shallow breathing only serves to
ventilate the dead space and is particularly detrimental during exercise.
In untrained individuals stroke volume decreases somewhat during
very rapid heart rates.
At rest the vessels going to the internal organs are primarily dilated and the
vessels going to
the absence of a
warm-up.
About 10% of fat tissue is
water and 75% of muscle tissue is water.
To maximize rehydration glucose and sodium are recommended with
water intake.
Although sodium is lost to the greatest extent salt tablets are not recommended during exercise because
water is pulled from the plasma to dilute the salt tablet in the small intestine, leading to further dehydration.
Sports drinks with added electrolytes are recommended over
water to prevent heat cramps.
During inhalation air becomes completely saturated with
water vapor.
The most important predictor of hyponatremia is considerable
weight gain during a race.
The redistribution of blood flow during exercise is necessary to bring needed oxygen to the
working muscles while maintaining blood pressure throughout the body's vascular network.
Maximum stroke volume is maintained in trained athletes at very high
workloads and heart rates indicating that there is still adequate time for the heart to fill.
The following are physiological consequences of dehydration:
• Weight loss from fluid loss exceeding 3% is associated with a 4 to 8% decrease in aerobic performance.• Reduction in stroke volume; cardiac output, and blood pressure which impairs cardiovascular function. Increase in blood flow to the GI tract and GI distress.Impairment in neural ability and mental functioning leading to central nervous system fatigue.Reduction in blood flow to the skin.
