Cardiovascular Adaptations to Endurance Training L.O.

Which of the cardiovascular variables is MOSTLY responsible for the increase in VO2max after endurance training?

an increase in cardiac output

Be able to explain the mechanism associated with these changes.

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Compare and contrast adaptations in the following major cardiovascular variables with endurance training during rest, submaximal, and maximal aerobic exercise:

LOOK AT PICTURE :/

Know the following values for resting and maximal (in untrained vs. trained people)...

a. Heart Rate (bpm) o untrained: • resting: • maximal: o trained: • resting: • maximal: b. Stroke Volume (ml/beat) o untrained: • resting: • maximal: o trained: • resting: • maximal: c. Cardiac Output (L/min) o untrained: • resting: • maximal: 18 - 22 o trained: • resting:

Explain why trained athletes have lower myocardial oxygen consumption compared to untrained individuals despite no differences in cardiac output at rest and during submaximal exercise.

• aerobic training allows for a given cardiac output to be obtained with a lower heart rate and higher stroke volume... Therefore, there is lower "Rate Pressure Product", meaning that the heart requires less myocardial oxygen demand because it is doing less work . o aka: trained people's hearts do less work to put out the same amount of blood as untrained people. Less work = less need for oxygen

Describe the changes in blood pressure volume that result from endurance training

• endurance training: o decreases resting BP and submaximal exercise BP o doesn't really change maximal exercise BP • blood pressure drops as a result of endurance training to an even greater extent for mild/moderate hypertensive people • even if you don't lose weight, your BP can still drop from exercise

Know the range of resting blood pressure reduction (as a result of endurance training) in healthy/fit and mild/moderate hypertensive individuals.

• healthy/fit individuals: o lower Systolic Blood Pressure by 3.0 mmHg o lower Diastolic Blood Pressure by 2.4 mmHg • mild/moderate hypertensive individuals: o lower blood pressure by about 5—7 mmHg

Describe the 3 mechanisms linked to changes in heart rate at rest and during submaximal exercise.

• mechanisms for decreased HR as a result of endurance training 1. increased parasympathetic activity via the vagus nerve to the SA node 2. training decreases the intrinsic firing rate of the SA node pacemaker tissue, which therefore causes the heart to beat less 3. increase in stroke volume, making the heart more efficient with each beat and therefore not having to beat as frequently

Know the similarities and differences with respect to the effects of aerobic training and resistance training on cardiac hypertrophy

• similarity: o ventricular chamber size increases o myocardial wall gets thicker • differences: o ventricular chamber size increases to a greater extent with Endurance training o myocardial wall gets thicker to a greater extent with Resistance training

Describe in detail the physiological mechanisms of Stroke Volume changes after chronic aerobic training

• stroke volume increases as a result of endurance training • Key factors responsible for training-induced increases in stroke volume: o an increase in End Diastolic Volume (EDV) due to the training-induced increase in blood volume and increased chamber size of the left ventricle o a decrease in End Systolic Volume (ESV) due to the increased thickness of the wall of the left ventricle

Describe the changes in cardiac dimensions that result from endurance training, and explain how these structural changes can improve cardiac function.

• the heart gets larger (aka hypertrophies) as a result of endurance training o the chamber size of the ventricle gets larger o the myocardial walls get thicker • the left ventricle increases in size to a greater extent than the right ventricle • these changes improve cardiac function by allowing for enhanced capacity for the heart to fill with blood, leading to a higher EDV and higher stroke volume (aka if the heart can be filled with more blood, that means it can pump out more blood with a single pump)