cardiovascular responses to exercise and training

cardiovascular changes during exercise: flow to brain

- increase slightly - auto regulation of brain arterioles maintains constant flow despite the increased MAP

venous return factors during exercise

- increased activity of skeletal pump - increase respiratory pump - sympathetically mediated increase in venous tone - great ease of blood flow form arteries to veins through dilated muscle arterioles

cardiovascular changes during exercise: blood flow to heart and skeletal muscles

- increases - active hyperemia occurs in both vascular beds, mediated by local metabolic factors

cardiovascular changes during exercise: EDV

- increases - filling time is decreased by high heart rate, but the factors favoring venous return compensate for this

cardiovascular changes during exercise: mean arterial pressure

- increases because the CO increases more than TPR decreases

what factors is VO2 max dependent on?

- it is depending on the cardiac output - arterial pressures ( respiratory system's ability to transport O2) - peripheral BF - central blood fow - hemoglobin total O2 - ability of muscles to use fuels and oxygen

what does maximal oxygen consumption tell us?

- it tells us about an invidiuals capacity to re-synthesize ATP under aerobic conditions - it tells us if a person is able to maintain intense exercise for a few minutes

what are the key adaptation to aerobic exercise that increase O2 delivery to muscles

- increase blood volume - increase EDV - increased ejection fraction - EDV and EF lead to increase stroke output and cardiac output - this all leads to an increase blood flow to the active muscle

HR threshold formulat

- HR threshold = HR + [0.60(HRmax - HR rest) ] *** memorize

acclimitization

- adaptations produced by changes in the natural environment

acclimation

- adaptations produced in a controlled laboratory experiment that stimulates high altitude of microgravity, hypoxic environments, and extremes of thermal stress

what is the recommended activity level for adults and children

- adults: 150 minutes a week - children: 1 hour a day

what are factors that influence aerobic training response

- age , genetics, sex - initial VO2 max - training intensity - training duration - training frequency - - overall health and co-morbidities

what are some determinants of VO2 max?

- age: it tends to decrease with age - sex - genetics - mode of testing

altitude sickness

- altitude sickness is discomfort due to ascension to high altitudes ( 8202 and higher ft) - symptoms: headache, breathlessness, nausea, vomitting, insomnia, fatigue, impaired vision - serious complications includes edema and brain edema

how does altitude training affect performance

- altitude training does not improve sea-level exercise performance

relationship between stroke volume and responses to exercise

- comparing trained athletes, sedentary students, sedentary students after training - findings: endurance athletes heart exhibited larger stoke volume during rest and exercise than untrained persons of same age - eight weeks of training substantially increase SV of previously sedentary students

cardiovascular changes during exercise: blood flow to viscera

- decrease - symp activation of blood vessel in abdominal organs an kidneys is increased

cardiovascular changes during exercise: total peripheral resistance

- decreases - resistance in heart and skeletal muscles decrease more than resistance to other vascular beds

main goals of aerobic training

- develop the capacity of CV system to deliver oxygen to working muscles - enhance the aerobic capacity of muscles: improve oxidative properties and energy utilization by myofibers

training and lactate levels

- endurance turning lowers blood lactate levels and extended effort before onset of blood lactate accumulation ( OBLA) during exercise of increasing intensity - how and why: 3 propose reasons: 1. decreased rate of lactate formation occurs during physical activity 2. there is an increase rate of lactate clearance 3. they have a combined effect of decrease lactate formation and increase lactate clearance

factors that limit exercise performance and VO2 max: peripheral blood flow

- flow to nonactive regions - arterial vascular reactivity - muscle blood flow - muscle capillary dentist - O2 diffusion - muscle vascular conductance - O2 extraction Hb-O2 affinity - venous compliance's and reactivity

what are the 4 main adaptations to decreased oxygen

- hyperventilation (increase ventilation) - stimulates production of new RBCs (after 5ishh days) - improve muscle function to increase oxygen transfer ( ike by increase mitochondria or increasing muscle myoglobin) - increase in loss of sodium and water in urine (why: helps concentrate the red blood cells but it puts you at risk for dehydration)

benefits of aerobic lifestyle

- improve cardiovascular fitness - decreased body fat, improve lipid profile - increased lean body mass - decreased risk for : CAD, HTN, stroke, diabetes 2, some cancers, osteoporosis - decreased risk of mortality - may prevent or slow down dementia - decreased risk of frailty - increased sense of wellbeing

heart rate and response to exercise

- in class we observed the different in VO2max and CO max between trained athletes, sedentary students, and former sedentary students - findings: athletes and trained students performs more intense physical activity and achieve higher oxygen consumption before achieving specifically sub maximal heart rattan than a sedentary student ( i.e. untrained athletes HR increase rapidly as oxygen consumption increased)

endurance training and cardiac output an oxygen uptake

- in highly trained individuals, there is an almost proportionate increase in maximal cardiac output that accompanies increases in VO2max -compaired to untrained people, trained athletes have higher CO max and VO2maxes

cardiovascular changes during exercise: cardiac output

- increase - heart rate and SV increase ( SV much more that HR)

cardiovascular changes during exercise: stroke volume

- increase - contractility increase due to increase sympathetic stimulation of the ventricular myocardium - increased ventricular end diastolic volume also contribute to increased stroke volume by Frank-starling mechanism

cardiovascular changes during exercise: blood flow to skin

- increase - sympathetic activation of skin blood vessels is inhibited reflexively by the increase in body temptation * review

cardiovascular changes during exercise: heart rate

- increase - sympathetic stimulation of the SA nod increase and parasympathetic stimulation decrease

heart mass and exercise

- long term aerobic training increases heart mass and volume with greater left ventricular EDV during rest and physical activity - this is called myocardial hypertrophy - magnitude of hypertrophy depends on type of exercise ( strength-power vs endurance etc)

relationship between cardiac output and O2 uptake

- omparing trained athletes, sedentary students, sedentary students after training - finding: trained athletes and students, CO increased linearly with VO2max - also an increase in max cardiac output represent th most important adaption to cardiovascular function with aerobic exercise

MAP equation

- recall MAP = CO * TPR - when you exercise CO increases a bit more than TPR decreases so MAP usually increases a bit

oxygen transport cascade

- the process of declining oxygen tensionfrom atmosphere to mitochondria - as one moves down through the bodyto the cell, oxygen is diluted down, extracted or otherwise lost, so that at cellular levelthe PO2 may only be 3 or 4mmH - so at high altitude the initial PO2 is really low, this contributes to arterial hypoxia - the arterial hypoxia that accompangnies the reduction in PO2 precipitates the immediate physiological adjustments to altitude and the longer term process of acclimatization

factors that limit exercise performance and VO2 max: central blood flow

- this includes cardiac output ( heart rate , stroke volume), arterial blood pressure, and oxygen transport capacity

factors that limit exercise performance and VO2 max: ventilation respiration

- this includes ones minute ventilation, ventilation : perfusion ration, oxygen diffusion capacity, Hb-O2 affinity, arterial oxygen saturation

factors that limit exercise performance and VO2 max: active muscle metabolism

- this includes: - enzymes and oxidation potential - energy stores and substrate availability - myoglobin concentration - mitochondria size and number - active muscle mass - muscle fiber type

maximal oxygen consumption

- this is the peak rate of oxygen use as physical exertion is increased: increment in world avocet this point must be fueled by anaerobic metabolism

what supports the increase in CO seen during exercise

- well recall than CO= SV * HR so increase in both leads to increase in CO seen during exercise - increase HR is due to decrease parasympathetic activity at the SA node and increase sympathetic activity - increase SV is de to incrreacsd ventricular contracililtiy ( increase ejection fraction) - in addition factors that increase the rate of venous return aid in increased CO

can you explain the integrated response to exercise?

- when you being exercise, 2 things are stimulated: brain exercise centers and exercising muscles that contract - when the brain centers are activate they active arterial baroreceptors - these baroreceptors decrease parasympathetic stimulation to heart and increase sympathetic output to the heart, veins, and arterioles in abdominal organs and kidneys - this results in increased CO and increase vassocnstriciton in abdominal organs and kidneys - at the muscle: contractions stimulate mechanoreceptors in the muscles and changes in local chemicals - the local chemical changes cause a dilation of muscle arterioles which results in increase blood flow to the muscles - local chemical changes also stimulate chemoreceptors in the muscles - in addition contractions stimulate muscles mechanreceptoscs - the chemo and mechanoreceptors create an afferent input that tells the medullary cardiovascular center to decrease parasympathetic stimulation to heart and increase sympathetic output to the heart, veins, and arterioles in abdominal organs and kidneys - this results in increased CO and increase vassocnstriciton in abdominal organs and kidneys

cardiovascular changes during exercise: pulse pressure

0 increases - SV and velocity of ejection of stroke volume increase