 due to hardening of arteries, excessive peripheral resistance (enhanced nervous tone or kidney malfunction)
 pressures of 250-300 for systole and >90 mm Hg for diastole
 aerobic exercise can modestly lower BP
 extent is unclear, but beneficial for normotensive and hypertensive individuals

 resting BP also lowers significantly, possibly due to higher circulating catecholamines after training
 decreased peripheral resistance to blood flow, decreasing BP
 exercise may enhance sodium elimination by kidneys

static and dynamic resistance exercise will increase peripheral resistance to BF
 even at light loads, e.g., 25% 1RM
 potential for harm for those with heart and vascular disease
 chronic resistance training does not appear to increase resting BP, and can blunt the response to a single bout

 dilation of blood vessels in working muscles will decrease TPR, increase BF to working muscle
 may see a small rise in systole, 140-160 mm Hg, then levels off
 diastole may increase or decrease 10 mm
Hg, or remain unchanged

 Increase in systole, mean, and diastole with increase in Q
 greatest changes are in systole, diastole may change only ~12%

 systole and diastole significantly higher than with leg exercise, even at same intensity
 may be due to smaller vasculature, increased resistance to flow
 heart will have to work harder

 after submax exercise, systolic pressure can be temporarily (2-3 hrs) depressed below pre-exercise levels
 B/c TPR remains low after exercise

 has its own blood supply
 has dense capillary network
 @ rest, normal BF to myocardium is ~200-
250 ml, 5% of Q

 @ rest, 70-80% of oxygen is extracted from the blood in coronary vessels
 in other tissues, @rest, ~25% of the oxygen is extracted
 coronary BF will increase during exercise to meet myocardial oxygen requirements, can increase 4-6X above resting levels

1. Increased myocardial metabolism causes dilation of coronary vessels
2. Increased aortic pressure forces a larger amount of blood into coronary circulation
 coronary BF is 2.5X greater during diastole than during systole
 heart has limited ability to generate energy anaerobically

 has a 3X higher oxidative capacity than skeletal muscle
 have the greatest mitochondrial density, well adapted for fat catabolism as primary source of ATP resynthesis
 Figure 15-9 this is the substrate use of the heart at rest, during exercise, and during recovery

 glucose, fatty acids, and lactate provide energy for the heart
 during heavy exercise, with a large concentration of lactic acid in the blood, the heart can use lactate for 50% of its total energy
 during prolonged submax activity, 70% of energy comes from fatty acids
 metabolic patterns are similar for TR and
UNTR, but TR have a greater contribution of fats to the total energy requirement

increase in myocardial contractility and heart rate will increase the demand for oxygen
 estimate myocardial workload and oxygen consumption, use product of peak systole and heart rate
 index of relative cardiac work





 called the double product, or rate-pressure product highly related to myocardial oxygen consumption and coronary BF
RPP = SBP X HR with training in cardiac patients, a higher RPP can be achieved before ischemic symptoms appear this measure is used in coronary heart disease patients

 rapid adjustments are necessary during exercise, possible by constriction and dilation of smooth muscular bands of arterioles
 additionally, venous capacitance vessels stiffen
 can rapidly redistribute blood to meet metabolic demand of exercise, while preserving adequate flow and pressure throughout the system

 changing diameter of blood vessels is most important factor regulating regional flow
 resistance to flow changes with vessel diameter (to the fourth power)
 reducing diameter by 1/2, causes flow to decrease 16X

1 in 30-40 capillaries is open at rest opening capillaries during exercise will
1. Increase muscle blood flow
2. Due to the increase in channels, increased blood volume can be delivered with only small increases in velocity of flow

3. Enhanced vascularization will increased the effective surface for exchange between blood and muscle cells
 local factors can increase the dilation of arterioles and precapillary sphinchters

1. Decrease in oxygen supply
2. Increase in temperature
3. increase in carbon dioxide
4. increase in acidity
5. increase in adenosine
6. increase in ions of magnesium and potassium
 these are autoregulatory mechanisms

 sympathetic and to small extent, parasympathetic portions of autonomic
NS provide a central vascular control
 muscles contain sensory nerve fibers which are sensitive to substances released in local tissue during exercise: causes vascular responses
 central regulation ensures that the area with the most need for oxygen gets the most blood flow

 norepinephrine is the general vasoconstrictor, and is released at certain sympathetic nerve fibers
(adrenergic fibers)
 other sympathetic fibers can release
ACH, causing vasodilation (cholinergic fibers)
 dilation of blood vessels is due more to a reduction in vasomotor tone than to an increase in action of either sympathetic or parasympathetic dilator fibers

 sympathetic nerves terminate in the medullary portion of the adrenal gland
 with activation, epi is released in large quantities, norepi in small quantities
 epi and norepi cause a constrictor response, except in blood vessels of the heart an skeletal muscle

 during exercise, hormonal control is minor in the control of regional BF
 BF is decreased to the skin, gut, spleen, liver, and kidneys as a general response

 Nerve centers above the medullary region are active both before and at the onset of exercise to cause increases in the rate and contractility of the heart, as well as to change regional blood flow
 sympathetic cholinergic outflow plus local metabolic factors acting on chemosensitive nerves and on blood vessels cause dilation in active muscles

 this reduces peripheral resistance, allowing for greater blood flow
 constriction adjustments will then occur in less active tissues as exercise continues, so that perfusion pressure can be eliminated factors influencing venous return:
1. action of muscle and ventilatory pumps
2. stiffening of the veins
3. increase in venous tone with an increase in Q

 Q = HR X SV
 primary indicator of the functional capacity of the circulation to meet the demands of
PA

 Direct Fick
 Q = O
2 consumed/ (a-v)O
2
Indicator
Dilution: examine an indicator dilution curve
 CO
2 rebreathing, indirect Fick
 Q = CO
2 production/ (v-a)CO
2
X 100

 Impedance
 SV
 Preload
 Afterload
 Contractility
 BP
 Systemic Vascular Resistance (SVR)
 Can index the values to body size