Physiology Health Exercise Lesson 9 z The Athletic

Physiology, Health & Exercise Lesson 9 z. The “Athletic” Heart

The “Athletic” Heart z Cardiac hypertrophy z Endurance training & LV z Maximal heart rate & cardiac output 2

Athletes are fitter than most people. Why? z Undergo regime of training z Exercise at more extreme levels z Exercise for longer periods of time z Have shorter recovery times z Lower HR at rest- 30 -40 bpm 3

Athletes are fitter than most people. z Strengthened cardiac muscle- capable of more forceful contraction- higher SV- even at rest z Athlete’s heart actually gets bigger- cardiac hypertrophy z Increase in protein synthesis in cardiac muscle fibres increase in contractile elements within each fibre increase in size 4

Athletes are fitter than most people. If you measure the size of cardiac muscle and volumes of the heart chambers using echocardiography and compare trained and untrained people: 5

Left ventricular mass (g) Left ventricular volume (ml) Untrained 210 100 Trained 300 180 What 2 conclusions can you draw from this data? 6

In non-athletes increase in CO is due to increase in HR z Is this the same for athletes? Max HR Max SV (bpm) (ml) Max CO (l/min) Untrained 170 120 20 Trained 195 180 35 Larger CO due to relatively greater increase in SV in athletes 7

Athletes are fitter than most people. z Increase in size of heart in athletes is temporary- if intensity of training decreases then heart returns to pre-training size. 8

Questions z 2006 SQA Q 1 in Physiol section to be completed in class. 9