EXB 101 Lecture 32-37
List health benefits of physical activity with respect to metabolism, bone composition, and risk of disease(s).
- Lower blood pressure, better insulin sensitivity - Lifetime physical activity builds ands sustains both muscle and bone into later life. Lowers the risk of atherosclerosis, colon and breast cancer, sarcopenia,and osteoporosis.
???What sort of behavioral and physiologic responses act to maintain fluid balance during exercise? What hormones are involved in this maintenance? What is the role of recovery in restoring fluid balance?
- The fluid and electrolyte conserving hormones secreted during exercise and recovery not only help us to complete the immediate work bout; they also prepare us for the next. -Hormones: Aldosterone ADH, not Renein: Na+ retention AVP: Water retention
What role might the water-conserving hormones secreted during exercise play in the recovery period? What if fluid-challenging workouts are repeated on a regular basis; how might this "add up"?
- The fluid and electrolyte conserving hormones secreted during exercise and recovery not only help us to complete the immediate work bout; they also prepare us for the next. -With repeated workouts, blood plasma volume will increase due to increased production of albumin created at the end of each workout. This increased plasma volume build up with repeated workouts
?????Describe how these hormones, when repeatedly released during repeated workouts, result in the increased water retention in chronic training. Why is increased protein synthesis of albumin (altered genetic expression) essential to retain this fluid specifically plasma volume?
-Albumin is a protein that maintains osmolarity; increases plasma volume through training because increase in albumin through training -Plasma increases, then albumin increases to maintiain plasma volume -
Does ambient temperature affect performance? What type of exercise, in particular?
-Ambient temperature affects performance if increased above 120F or below 70F -Mainly effects endurance exercise because our body needs to thermoregulate during endurance training as opposed to strength training
How does blood flow to the skin play a role in heat loss or retention?
-Blood flow is removed from external areas (like skin) in order to decrease exchange with environment
Describe the three main physiological mechanisms by which the body holds temperature ~constant.
-Cardiovascular -Thermoregulatory -Metabolic
Which 2 capacities are known to increase with endurance training, and predict endurance performance?
-Cardiovascular abilities -Mitochondria density
Name two different cancers whose incidence may be reduced by regular exercise training.
-Colin cancer -Breast cancer
Name 4 common, expensive, debilitating diseases that may be prevented/postponed with exercise training.
-Coronary Athlerosclorosis (#1 cause of death in America) -Osteoporosis -Sarcopenia (muscle loss) -Cancer
We normally consider the doubling of stored glycogen, and the increase in sustainable aerobic workload after training as "metabolic" adaptations. Make the (somewhat unusual) argument that these changes are also part of the thermoregulatory adaptation to sustained work.
-Glycogen is stores with water -This water is released when glycogen is released to be broken down -Water can then be used to cool down the body
Why does hydration level affect heart and core body temperature during exercise?
-Having enough water is important for sweating -Also important for maintaining plasma volume, which inessential for transporting heat and maintaining hear rate -Heart rate will increase with decreased plasma volume -Core body tem drops, heart rate drops
Explain how specificity of training is related to increase in strength (e.g., training with only 1 arm)
-If you only train one arm, the other arm will get stronger through neural activation (bilateral transfer: from trained limb to untrained limb) -After that first month, the one arm being trained will get larger than the untrained arm and therefore stronger (hypertrophy)
Discuss the skeletal differences between genders in terms of Q-angles and frequencies of ACL injuries
-Larger Q angle(angle of femur from hip to knee)= larger frequency of ACL injuries
How do males and females compare in hypertrophic response to heavy resistance training?
-Males and females have the same hypertrophy rate in relation to their size
Describe the differences in endurance performances between genders, like cycling and running
-Men outperform women in running and cycling due to having naturally less fat and more lean mass. -Men also have more [Hb]
The faster male "best time" performances (10%) in endurance running are due primarily to what 2 factors?
-Men outperform women in running and cycling due to having naturally less fat and more lean mass. -Men also have more [Hb]
What are the major routes and amounts of our daily obligatory fluid losses?
-Most output is in urine (1500ml) -Skin (600) -Lungs (exercise more increases water loss through lung) (350) -Feces (100)
How would you measure power in a lab?
-Power is usually measured using short-term, high intensity work tasks -Wingate test (30s anaerobic exercise on a bike)
When during life do the sex differences in muscle mass distribution develop?
-Puberty
What sex differences exist that affect physiologic function?
-Q-Angle -Muscle mass -Proportion placement of muscle and fat
Distinguish between relative and absolute power.
-Relative power is related to cross sectional area; men and women have the same relative power -Men have more absolute power because they have more lean body mass
Which types of athletic events would show the greatest differences, and which would show the least differences, in performances between men and women (on average).
-Running, cycling, gymnastics, bench presses, etc. Would show the most difference -Long-distance swimming would show the least difference
What happens to skeletal muscle respiratory capacity with endurance training?
-Skeletal muscle respiratory capacity will increase with endurance training due to: -Increase in mitochondria which leads to -Increase in oxidative enzymes -Increase in capillary density
Which of these three functional attributes is visible to the naked eye?
-Strength
Name two separate reasons why exercise is the greatest common challenge to fluid homeostasis (big hint: one is an intra-compartmental shift, the other an extra-corporeal loss).
-Sweat -Blood (plasma)volume decreases due to a shift into the interstitial space of the working tissue
Why is there less difference between male and female world class swimming performances than between male and female running performances?
-Swimming requires a distribution of fat both to keep warm, but especially to keep afloat (legs); women have more fat generally, so this alone increases swimming performance
Exercise "alone" (without an accompanying calorie restriction) rarely results in large scale loss of body fat because.....?
-There is no calorie restriction (normal mammals invest sufficient calories to make up for the calorie deficit)
Compare the relative hypertrophy seen in men Vs. women in response to equivalent weight training
-There is the same ratio of hypertrophy for men and women with equivalent loading
How can a trained individual exercise at a 50% higher workload (and heat production), and yet wind up with a smaller rise in core temperature, and a more stable cardiovascular system than before training?
-Through training, the body produces -more plasma volume (increases heat flow while decreasing heart rate) -wetter, cooler skin, sooner (more sweat sooner) -more mitochondria to produce water through respiration -Increased levels of skin blood flow -Increase in glycogen storages which store water that can be utilized
Why does the anaerobic threshold occur at a higher % VO2max in a trained vs. untrained individual
-Trained individuals have more mitochondria in muscle fibers, which means they have more oxidatative capacity -More oxidative capacity leads to the utilization of more fats over carbs -This causes lactate to be produced less -More oxidative capacity also causes lactate to be converted into pyruvate at a greater rate, causing it to take longer to build up lactate in the muscle
What is the most flexible route for adjusting water losses? The most flexible route adjusting water intake?
-Urine is adjustable for water loss -Fluid intake is the most flexible rout for adjusting water intake
The drop in urine formation and increase in urine concentration that occur during and after exercise is dramatic. What two physiological changes accompanying exercise create this change in renal function?
1) An decrease in blood circulation through the kidney decreases the amount of urine formed 2)Hormones retain arterial tone while decreasing electrolyte and water loss (Renin= retain Na+, AVP=water retention, increases thirst)
Name at least two potential mechanisms that explain how exercise training may preserve brain function.
1. Cardiovascular Support - Multi-infarct Dementia - Close control of Hypertension, Diabetes, and Cholesterol all reduce the rate of dementia onset 2. 1980's: Acute exercise, memory, and Vasopressin - Vasopressin (ADH) associated with short-term memory 3. Neurogenesis in Adults Driven by Neurotrophic Factors - Brain- Derived Neurotrophic Factors (BDNF) - Glial- Derived Neurotrophic Factors (GDNF) as well as increased Neuron Interconnectivity -"Dendritic Ramification"
Cite one or more recent research findings that suggest that regular exercise improves/preserves the brain.
1. Running enhances neurogenesis, learning, and long-term potentiation in mice - exercise stimulates hippocampal neurogenesis 2. Brain-derived neurotrophic factor - supports the survival of existing neurons, and promotes the growth and differentiation of new neurons and synapses. This occurs especially in the hippocampus where learning and memory take place.
If a 55 kg female is exercising hard on a moderately warm day without fluid replacement, and is losing 1.2 liters of sweat per hour, how long will it take before she reaches a loss of 3% of her body weight? (Both performance and thermoregulation dramatically decline beyond this level of dehydration.)
1.65 (L)/1.2 L sweat= 1 hour 22 minutes
What is the energy cost (kcals) of walking a mile? Of running a mile?
100 kcal/mile for walking and running
What is the daily energy cost to maintain 1 lb (or 1 Kg) of lean tissue at rest?
14 kcals/lb of lean body mass
If someone is systematically under-eating relative to her calorie need by ~500 Kcal each day (a 500 Kcal deficit), how long will it take her to lose one pound of fat?
500/3500= 7 days
If the ambient (dry bulb) temperature is 85˚ F and the relative humidity is 100%, what is the heat index?
85 + 100 = 185
Under what conditions does the body's temperature regulating system fail?
95% humidity, 95 F (because your sweat can't evaporate)
Endurance
Ability to sustain a given work task
What percentage of the lean body mass is generally water?
About 75%
So, during a calorie-restriction, what are the roles of aerobic vs. resistive exercise?
Aerobic exercise: if you only do aerobic exercise you will lose lean body mass. Resistive exercise: mTOR activation with resistance training preserves lean body mass, so you will use fat as a fuel source instead of lean body mass.
Name 3-4 mechanisms allowing elite female distance runners to out-perform 99% of the young adult males?
An elite female distance runner can outperform 99% of the young adult male population, on the basis of: 1. a lower body fat (11-13%) than all but the leanest 20% of males 2. compensating for the lower hemoglobin level with an overall blood volume expansion... 3. combined with an increased capacity to pump this larger blood volume (SV max and Q max) 4. and a greater ability to extract oxygen at the muscle level, based on greater capillary density, higher proportion of slow-twitch fiber, mitochondrial and oxidative enzyme content.
Define atherosclerosis and list the associated symptoms
Atheroslerosis is plaque built-up in the arteries. -The associated symptoms is high blood pressure and cut off to the blood flow leading to myocardial infarct, cerebral infarct, gangrene of extremities, and abdominal aortic aneurysm.
What is the general cause of a myocardial infarction (heart attack)?
Atheroslerosis of the coronary arterties
In what special situation does instituting regular exercise often (but not always) result in a 5-10% loss of body weight in free-feeding humans or rodents?
Change from sedentary state to regular training (ad libitum feeding) may lead to loss of ~5% Bwt.
What is the leading cause of death in the U.S. (for both males and females)?
Coronary Athlerosclorosis
Which of the follow is/are true: Dr. Shaffrath thinks we should all be losing fat through a program of sustained calorie deficit...OR... Dr. Shaffrath feels we should all be on weight maintenance programs for most of our lives, with a central focus on lots of exercise and the unrestricted eating of fresh, healthy, minimally processed foods.
Dr. Shaffrath feels we should all be on weight maintenance programs for most of our lives, with a central focus on lots of exercise and the unrestricted eating of fresh, healthy, minimally processed foods.
What is the total energy cost of exercising on a bike ergometer at the ARC @ 150 Watts, for 30 minutes?
Efficiency= .25 150Watts x 4 =600 Watts= Joules/sec (600Joules/sec)/(14187J/kcal)x(60sec)/(minx30min) =258kCal
How does endurance training affect the % of VO2max that can be maintained during prolonged work?
Endurance training affects the % of VO2max that can be maintained during prolonged work is due to increase cardiac output and increase oxygen extraction by muscle.
What is the effect of endurance training on max stroke volume?
Endurance training increases max stroke volume
Although the body's non-sweating water losses are reduced by renal mechanisms during exercise, there is still a net loss of fluid by the end of most workouts. How is this fluid regained?
Fluid is retained by thirst -Need water after 1 hour during most workouts
True or False: Most people who begin an exercise program will be measurable healthier within 1-2 months, even if they fail to lose any body weight.
Foe Show
75% of the energy liberated by metabolism is in the form of __________
Heat
What is the significance of blood volume increasing more than hemoglobin following training?
Increase in plasma volume increases albumin which increases fatty acid transport
In terms of calorie balance, what is the necessary prerequisite for loss of body fat stores?
Kcal taken in< Kcal removed
In which body compartment (fat, lean, solids) does most of the body's water reside?
Lean mass holds 75% of the water
What is the minimal amount / intensity of physical activity recommended to improve health? How does this differ from the amount / intensity of exercise required to enhance fitness (VO2max or Lean Body Mass)
Low intensity or modest frequency and duration of exercise is recommended to improve health. To enhance fitnesss or functional development it takes longer duration, higher intensity, and more frequency.
What is the total energy cost for a 50 kg person who works at 8 Mets for 1 hour?
METs x Bwtkg = Kcals/Hr 8 METs x 50 kg = 400 kcal/Hr
Define specific strength. Units?
Max force per unit cross sectional area (CSA) Units: Newtons/cm^2 or Kg/cm^2
Explain the adaptations that occur in the "cardiovascular machinery" and the "muscle machinery" that allow for both an increase in VO2max and performance.
More oxydative enzymes
CNS regulation of body temperature is: feed-forward? central command? negative feedback?
Negative feedback of Sweating and cutaneous vasodilation (surface of skin)
After 2 weeks of training, the increases in strength seen are due to ______________
Neural activation
Describe the role that neural activation plays in peak tension development
Neural activation causes muscle strength to increase after two weeks of training
How important are testosterone levels in determining strength increases due to training in human adults?
Not important -Testosterone levels don't contribute to hypertrophy in adults
How important is fiber type with respect to determining strength (peak tension)?
Not important because it is cross sectional read that determines strength
Names: Pathologically low bone density: . The "lessening of the flesh": .
Pathologically low bone density: osteoporosis "lessening of the flesh": sarcopenia
Strength
Peak tension/ max force
What are the ACSM exercise recommendations to improve fitness?
Recommended Amount and Type of Physical Activity 1. Aerobic Frequency = 2 to 5 days/week Intensity = 65-90% of HRmax (HRmax = 220 - Age) Duration = 20 to > 60 minutes 2. Resistance Frequency = minimum 2x/week Intensity = 8-12 repetitionmax; 1-3 sets Duration= 18 -20 different exercises 3. Flexibility Everyday, or "in context of other exercise"
What role does exercise plan in the maintenance of body weight in free-feeding individuals?
Regular exercise is perhaps the most important factor in maintenance of body weight.
What is the heat index? How is it calculated?
Reletive humidity + temp. in deg. F =
Name two hormones secreted during exercise that help to restrict further water loss and maintain blood pressure during each acute exercise bout.
Renin - retains NA+ AVP (angio vasopressin) - H20 retention and increases in thirst.
What factors cause the increase in stroke volume with training?
SV increased by increase in: -Preload -Contractility
What is the relationship between cardiac output and TPR with endurance training?
TPR= total peripheral resistance The cardiac output will increase and the TPR will decrease to maintain mean arterial pressure.
Over the range of physical activity, who gets the greatest change in health per unit increase in activity?
The "doing nothing" to "doing a little bit" gets the greatest change in health per unit increase in activity.
Hint, if you're stuck on #5: What is the World Health Organization's recommendation regarding H20 Intake?
The World Health Organization recommends a sliding scale of 1 mL H2O per Kcal of energy expenditure.
How does the body accelerate heat loss during a single exercise bout (by what mechanisms)?
The body accelerates heat loss during a single exercise bout by a negative feedback system of sweating & skin perfusion. - Integrator for sweating - Integrator for vasodilation (having blood got to the skin) - Integrator for venodilation (opening the veins to the skin)
Why is the concept of "8 cups (pints, liters, tankards) of water a day" too simple? (Hint: calculate the water needs for a 45 kg female swimmer who requires1400 kcal/day to maintain body weight in the sedentary off-season. What are her water needs when she is swimming 9000+ yards per day (3 hours) and must consume 3200 kcal/day to maintain her weight?)
The concept of "8 cups (pints, liters, tankards) of water a day" is too simple because daily fluid losses must be replaced by an equal fluid intake. - In the sedentary off-season, a 45 kg female swimmer needs 1400 mL of water. - When she is swimming 9000+ yards, she needs 3200 mL of water.
What accounts for the majority of the strength differences between average individuals and athletes?
The cross sectional area of the muscle (# side-by-side sarcomeres) => bigger muscles -Both trained and untrained people will have the same specific strength
What is the difference in a person's interior (emotional, subjective) experience in each of the two conditions described above?
The difference in a person's interior experience of loss of body fat stores is predicable, powerful feelings due to calorie deficit such as irritability, tiredness, and hunger
List the components of a general training program
The general components of a general training program is to have a balanced and diversified "diet" of chronic activity; a comprehensive lifestyle of a wide range of physical activities (of which workouts are just one element). This includes everyday activity, workout throughout the week including flexibility, aerobic/ recreational activities, and muscle strengthening, and cutting down on screen time.
What, and Where, is the key central nervous controller of body temperature?
The hypothalamus controls body temperature from the brain
Strength is proportional to ______________
The number of side-by side sarcomeres (NOT fiber type!!)
Explain the various factors that are involved in peak muscular force generation (i.e., strength) and how they adapt to strength training
The number of side-by side sarcomeres can agent peak tension
How many Kcals are in a pound of human fat?
There are 3,500 kcals in 1 lb of human fat.
Are there sex differences in muscle fiber type distribution and/or "specific strength'
There is no difference in muscle fiber type or distribution of muscle fiber types. The difference in specific strength is due to where nature has placed the lean mass and how much surface area (lean mass) is in one area
Where do body fluids go during exercise?
They go into the blood plasma and are also released as sweat (water from glycogen, water from respiration)
What is the most likely outcome for an apparently healthy person begins to lose lots of body weight (> 10 lb) without effort, exercise, or other conscious intervention (medical prognosis of spontaneous weight loss)?
They need medical advice
What three elements of thermoregulatory system are altered by training to create an expanded capacity?
To change the response to heating in order to reduce the "Thermal Deficit": 1. earlier onset of sweating 2. more sweating per unit of heating 3. increased plasma volume
What happens to total blood volume with endurance training?
Total blood volume increases with endurance training
Explain the difference between muscular strength and power. What factors determine peak muscular power? How do these factors adapt to strength training?
VO2 max and lactate threshold predict power = (vo2max x lactate threshold)
What is the minimum "essential" % fat for each sex?
Women: 12% Men:5-6%
What are the normal ranges of %body fat for each sex?
Women: 12-24% Men: 5-17%
Discuss the differences in fat distribution between the sexes.
Women: carry fat on their thighs Men: Carry fat on their back and abdomen
Power
Work/ Time (Watts)
Can endurance performance still increase if VO2max stays the same during endurance training? How?
Yes, endurance performance can still increase if VO2max stays the same during endurance training because performance has to do will a lot of things such as speed, improve oxidize different substrates, increase plasma volume.
How does the condition above differ from what is necessary to maintain body fat and weight?
kcal taken in > or = Kcal removed -Chronic exercise is the best predictor of weight maintenance