THE CARDIOVASCULAR SYSTEM Anatomy Acute Exercise Chronic Exercise

Adaptations to Chronic Exercise Increase VO2max. What does a higher VO2max indicate? What is responsible for an increase in VO2max? VO2max = Qmax x a-vO2 difference

CARDIAC OUTPUT AND TRAINING

Cardiac Output What is responsible for a higher maximal cardiac output? Q = HRmax x SVmax Does HRmax increase with training? Does SVmax increase with training?

Stroke Volume What is responsible for a higher SVmax?

LEFT VENTRICULAR HYPERTROPHY

STROKE VOLUME AND TRAINING

DIFFERENCES IN EDV, ESV, AND EF Filling Volume Residual Volume Percent of Total Volume Ejected

Stroke Volume A larger and stronger heart produces an increase in stroke volume at rest, submaximal exercise and maximal exercise A higher stroke volume at rest and submaximal exercise will allow for a lower heart rate without changing cardiac output

Stroke Volume A higher maximal stroke volume will produce a higher cardiac output A higher cardiac output will produce a higher VO2max A higher VO2max indicates a greater ability for aerobic energy production

Stroke Volume What type of aerobic training is most effective in strengthening the heart and thus increasing stroke volume?

Heart Rate What affect will a larger SV have on resting HR? What affect will a larger SV have on submaximal exercise HR? What affect will a larger SV have on maximal exercise HR?

HEART RATE AND TRAINING

Heart Rate Recovery Period w The time after exercise that it takes your heart to return to its resting rate w With training, heart rate returns to resting level more quickly after exercise w Has been used as an index of cardiorespiratory fitness w Conditions such as altitude or heat can affect it w Should not be used to compare individuals to one another

HEART RATE RECOVERY AND TRAINING

Blood Flow What other changes occur with training that allow for an increase in blood flow to the muscle? Capillaries? Blood?

Capillaries

BLOOD AND PLASMA VOLUME AND TRAINING Blood Volume? Red Blood Cells? Hematrocrit? Viscosity? Blood flow distribution?

Blood Volume and Training w Endurance training, especially intense training, increases blood volume. w Blood volume increases due to an increase in plasma volume (increases in ADH, aldosterone, and plasma proteins cause more fluid to be retained in the blood). w Red blood cell volume increases, but increase in plasma volume is higher; thus, hematocrit decreases. w Blood viscosity decreases, thus improving circulation and enhancing oxygen delivery. w Changes in plasma volume are highly correlated with changes in SV and VO2max. .

a-v O2 difference What else needs to happen beside an increase in blood flow and blood volume in order for VO2max to increase? Capillaries Myoglobin Mitochondria

Cardiovascular Adaptations to Training Cardiac Output w Left ventricle size and wall thickness increase w Stroke volume increases, as does Qmax and VO2max w Resting and submaximal heart rates decrease w Maximal heart rate stays the same or decreases w Blood volume increases w Increase in a-v O2 difference w More capillaries, myoglobin and mitochondria a-v O2 difference

Cardiovascular Adaptations to Training VO2 Q HR SV a-v O2 Difference Rest Same Dec Inc Submax (same intensity) Performance Max

Blood Pressure and Training w Blood pressure changes little during submaximal or maximal exercise. w Resting blood pressure (both systolic and diastolic) is lowered with endurance training in individuals with borderline or moderate hypertension. w Blood pressure during lifting heavy weights can cause increases in systolic and diastolic blood pressure, but resting blood pressure after weight lifting tends to not change or decrease.

Lactate Threshold What affect would an increase oxygen supply to the muscles during exercise have on the lactate threshold? What affect would this have on aerobic performance?

BLOOD LACTATE AND TRAINING

At Rest At rest the heart can supply all the needed oxygen with a cardiac output of 5 liters per minute. If the resting stroke volume is higher due to aerobic training, how will the resting heart rate be different? What about parasympathetic stimulation?

Submaximal Exercise Before training, running at 6 mph required a cardiac output of 15 liters. Also, before training this required a heart rate of 140 bpm Since after weeks of training stroke volume increases, what will happen to the heart rate while running at 6 mph? Why? What would happen to the running speed if the trained person now ran at a heart rate of 140 bpm? If the lactate threshold used to occur at 6 mph, at what speed will it occur now? Why?

Maximal Exercise Increase in VO2max Increase SV and blood volume Indicator of aerobic fitness level

CHANGE IN RACE PACE, NOT VO2MAX .

Aerobic Endurance and Performance w Major defense against fatigue which limits optimal performance. w Should be the primary emphasis of training for health and fitness. w All athletes can benefit from maximizing their endurance.

Respiratory Adaptations to Training w Static lung volumes remain unchanged; tidal volume, unchanged at rest and during submaximal exercise, increases with maximal exertion. w Respiratory rate stays steady at rest, decreases with submaximal exercise, and can increase dramatically with maximal exercise after training. w Pulmonary ventilation increases during maximal effort after training. (continued)

Respiratory Adaptations to Training w Pulmonary diffusion increases at maximal work rates. w The a-vO2 diff increases with training due to more oxygen being extracted by tissues. - w The respiratory system is seldom a limiter of endurance performance. w All the major adaptations of the respiratory system to training are most apparent during maximal exercise.