Chapter 34: energetics and physiology of Exercise

Question 1

What is the effect of acute exercise on heart rate, stroke volume, cardiac output and muscle blood flow?

Answer 1

HR increase
SV(volume of blood transported during ventricular systole) increases
CO=HR*SV= volume of blood pumped thru ventricles with each heart beat= about 5L/min at rest. also increases

Question 2

What muscle regulate muscle blood flow

Answer 2

precapillary sphincter-band of smooth muscle that adjusts blood flow into capillaries mainly in the mesenteric microcirculation

Question 3

Why does HR increase with acute exercise?

Answer 3

sensory input from proprioreceptors and chemoreceptors

Question 4

why does SV increase with acute exercise ?

Answer 4

increased venous return (starling mechanism)

Question 5

Why does muscle blood flow increase with acute exercise?

Answer 5

local control of vasculature, CNS, and hormonal mechanism

decrease in total peripheral resistance

Question 6

What effect does chronic aerobic exercise have on heart rate, stroke volume, cardiac output and muscle blood flow?

Answer 6

stronger ventricular contractions lead to increase stroke volume and decreased heart rate to maintain a certain CO.
increased perfusion in skeletal muscle and decrease in MAP(mean arterial pressure)= CO *Pr (total resistance which blood must be pumped)

Question 7

What is the primary fuel used in low intensity exercise?

Answer 7

plasma fatty acids

Question 8

What is the primary fuel used in moderate intensity exercise?

Answer 8

fatty acids mainly and some glycogen

Question 9

What is the primary fuel used in high intensity exercise?

Answer 9

mainly glygen storages

Question 10

What is a type I, slow-twitch skeletal muscle

Answer 10

highly oxidative (more mitochondria)
increased lipid stores
fatigue resistant

Question 11

What is a type II, fast-twitch skeletal muscle

Answer 11

lower mitochondria and lipid than type 1
fatigue more easily
higher glycogen stores

Question 12

What is a type 2x, slow-twitch glycolytic skeletal muscle

Answer 12

lowest mitochondria and lipid content of all skeletal muscles
higher glycogen storages
fatigues quickly

Question 13

Effect of insulin on glucose metabolism

Answer 13

cause GLUT 4 to transport glucose to be stroed as glycogen and FAs are transported into myocytes and stored as TG
increase in ATP and creatine phophate

Question 14

Effect of exercise on glucose metabolism

Answer 14

1. ATP/CP activiated and used quick
2. Anaerobic glycolysis
   short
   low ATP produce lactic acid
3. aerobic metabolism
   high ATP yield
   produce co2 and h2o
   long term

Question 15

What is VO2 max

Answer 15

• maximum capacity to transport and utilize oxygen during maximal exercise aka aerobic capacity
• gold standard of physical fitness
• measured in lab with increasing exercise until O2 consumption plateaus.
• can be increased by 10%-20% with exercise training

Question 16

What is lactate threshold? what

Answer 16

point where lactate production is more than clearance during increasing exercise intensity. lactic acid measured in the lab in the blood during increasing exercise intensity.

Question 17

Effect of lactate threshold on physical fitness. How does chronic exercise training affect lactate threshold.

Answer 17

exercise increases the threshold by increase VO2 so more energy is derived from aerobic processes

Question 18

Metabolic response to training?

Answer 18

increased mitochondria
increase capillary density in muscles
increased utilization of FAs