Unit 6 Day 4 Cardiovascular Effects of Training

Unit 6, Day 4: Cardiovascular Effects of Training PSK 4 U

From Yesterday. . . Take out your mini-lab and graphs: 1. What did you notice about your heart rate as you exercised over time? 2. What did you notice about your cardiac output? 3. Any questions?

Acute Effects of Exercise �When we begin to move, our skeletal muscles require more fuel (more ATP) which becomes most accessible through cellular respiration �Cellular respiration requires oxygen �Therefore, when we exercise: �HEART RATE increases �STROKE VOLUME increases slightly *see graph �. . . As a result, CARDIAC OUTPUT increases

What enables the increase of SV? �Frank Starling Law: the ability of the heart to stretch and increase the force of the contraction and thus the amount of blood that is ejected. �Similar to stretch in skeletal muscle (skeletal muscle contracts most forcefully when it is slightly stretched longer than resting length) �This is mostly affected by the amount of blood returned to the heart - VENOUS RETURN

VENOUS RETURN �(VR) increases during exercise by �Venoconstriction �The skeletal muscle pump �The thoracic pump �Nervous stimulation (increased HR)

Cardiac Output Distribution During Exercise See p. 245 in textbooks

What happens with training? �Q (cardiac output) �Rest �Exercise 5 -6 L/min 35 -45 L/min �Stroke volume �Untrained male at rest �Highly trained male m. L/beat �Highly trained endurance m. L/beat 70 -80 m. L/beat 100 -110 150 -170 Therefore, with training we can pump out more blood with less beats (HR) which

The Cardiovascular Effects of Training �Read pages 246 -247 in your textbooks. �Answer questions on handout!