Thermoregulation II

What are heat cramps due to?

Loss of Na+ and H20

What is heat exhaustion due to?

Decrease in skin blood flow

What is heat stroke due to?

Stop in sweating

When is proper fluid intake critical for exercise?

Beyond 45 min

What are key adaptations of exercise training in a hot environment?

1. Earlier onset of sweating

2. More sweat per sweat gland

3. Sweat is more dilute

T/F: Plasma volume increases in heat acclimation

True

T/F: Skin blood flow is improved in heat acclimation

True

T/F: Core temp is better maintained in heat acclimation

True

T/F: Increase in exercise tolerance during heat acclimation

True

When does acclimation occur?

Rapidly

When is acclimation more effective?

When training

Why does stroke volume decline during exercise in heat?

Due to decrease in venous return

What does increase in heart rate maintain?

Cardiac output (CV drift)

What is the goal of fluid replacement?

To maintain plasma volume so that CV adjustments and sweating can progress at optimal levels

Fluid replacement beverage should:

1. Maintain hydration

2. Reduce fatigue

3. Improve performance

4. Prevent heat disorders

In gastric emptying sports drinks should ___ ___ ___

Exit stomach quickly

H20 is absorbed in ___ not ___

Small intestine, stomach

Rate of gastric emptying ___ as carbohydrate content ___

Declines, increases

Rate of gastric emptying ___ as electrolyte ___

Declines, increases

What do sports drinks balance?

Fluid and carbohydrate delivery

What % of carbohydrates is optimal if no Na+?

10%

What does ACSM recommend % carbohydrates and Na+

6-8% Carbohydrate + 5% Na+

What are heat cramps primarily due to?

Loss of H20 and Na+

What can heat cramps be resolved or prevented with?

Proper fluid and salt intake

What is cardiovascular drift?

The gradual drifting of variables as one is exercising