W7 - Heat_Performance

Question 1

What is the relationship b/w heat & match play performance?

Answer 1

Decrease in overall performance, but particularly in HSR (even in self paced HSR). Body will prioritise dissipation of heat over movement.

Question 2

What is the relationship b/w core body temperature & endurance performance?

Answer 2

Those who’s core temperature increased quickly as a → of the warm up had > core temp at the end than those that didn’t. However, finish times were similar irrespective of core temp

Question 3

Are long distance athletes quicker or slower if it’s hot?

Answer 3

Slower. The hotter we get the worse our performance

Question 4

Are single sprint athletes quicker or slower if it’s hot?

Answer 4

Quicker

Question 5

Are middle distance athletes quicker or slower if it’s hot?

Answer 5

F affected more (slower) than M with limited affect on M performance

Question 6

Name 4 ways that athletes can try to manage their response to heat eg pre cooling

Answer 6

Accimatisation; Pre Cooling; Fluid Consumption Strategy; Recovery Strategies

Question 7

How does wind speed affect performance?

Answer 7

Wind helps evaporation of sweat, but doesn’t need to be fast (16km/h) just moving

Question 8

What happens to our Cardiovascular system in hot conditions?

Answer 8

• Increased HR • Decreased SV
• Decreased CO • ↓ BP. Can even get CV drift, where HR ↑ to a lvl where can no longer continue

Question 9

What temperature is Thermo Neutral?

Answer 9

Approx 20-25 °

Question 10

How does cerebral blood flow change with heat and how can this affect performance?

Answer 10

↓ - Some evidence that prolonged high-intensity exercise in the heat can:
• < attentional focus
• < mental readiness
• < wakefulness
• < mental readiness
• < arousal

Question 11

How does heat affect maximal O2 uptake?

Answer 11

↓ - but doesn’t happy immediately and relise on ↑ in ‘mean body temperature’ (weighted average of core and skin i.e. whole body temp)

Question 12

How does heat affect skeletal muscle blood flow?

Answer 12

• > blood flow perfusion
• > oxygen delivery
• > contractile function (velocity/force) • > nerve conduction velocity
Improved jump and sprint performance. Heat can be skin and/ or core temp - i.e. just standing in sun can → in these

Question 13

How does heat affect metabolism?

Answer 13

Prolongedexerciseintheheat:
• > muscle glycogen utilisation
• > anaerobic metabolism
• > lactate accumulation • > Central limitation of muscle activation (fatigue) • < Force production

Question 14

How does heat affect fatigue?

Answer 14

↓ VO2 Max; ↑ O2 demand but ↓ O2 delivery; ↓ endurance time and time to anaerobic threshold; overall ↓ in time to volitional exhaustion or ↑ fatigue

Question 15

The way heat affects volitional exhaustion is multifactorial. What are the 5 factors?

Answer 15

1. Psychological factors (experience and expectations eg if lived in Darwin all life, will power, motivation, mood, pain tolerance. 2. CNS requirements eg cerebralblood temp and neurotransmitter depletion 3. CV requirements ↓ SV, ↓ CO, ↑ HR 4. Peripheral Recepttors - altered muscle fn 5. Respiration ↑ ventilation, ↓ O2 tfr

Question 16

Whats the difference b/w acclimation and acclimatisation?

Answer 16

Acclimation:
• Physiological changes elicited from experimentally induced adaptations to certain climatic conditions (e.g. heat chamber, warm baths).
Acclimatisation:
• Physiological and behavioural changes which occur due to a lifetime or extended exposure to a stressful natural environment (e.g. seasonal or geographical).

Question 17

Improved cutaneous blood flow is an acclimatisation response, what’s the effect?

Answer 17

Transports metabolic heat from deep tissues to skin

Question 18

Effective distribution of cardiac output is an acclimatisation response, what’s the effect?

Answer 18

Appropriate circulation to skin and muscles to meet demands of metabolism and thermoregulation; greater blood pressure stability during exercise

Question 19

Lowered threshold for sweating is an acclimatisation response, what’s the effect?

Answer 19

Evaporative cooling begins early during exercise

Question 20

More effective distribution of sweat over skin surface is an acclimatisation response, what’s the effect?

Answer 20

Optimum use of effective body surface for evaporative cooling

Question 21

Increased sweat output is an acclimatisation response, what’s the effect?

Answer 21

Optimum use of effective body surface for evaporative cooling

Question 22

Lowered salt concentration of sweat is an acclimatisation response, what’s the effect?

Answer 22

Diluted sweat preserves electrolytes in extracellular fluid

Question 23

Lower skin, core temperature, and heart rate for standard exercise is an acclimatisation response, what’s the effect?

Answer 23

Frees greater proportion of cardiac output to the active muscles

Question 24

Less reliance on carbohydrate catabolism during exercise is an acclimatisation response, what’s the effect?

Answer 24

Carbohydrate sparing