Exam 10: Physical Activity- Thermoregulation

Physical activity in hot, humid weather produces a sweat rate of more than 1 liter per hour, with a sweat-sodium concentration ranging between 20 and 100 mEq/L.

With prolonged physical activity in the heat, sweat loss can deplete the body of this much sodium.

Heat acclimatization refers to the physiologic adaptations to improve heat tolerance.

Characteristics of heat exhaustion include weak, rapid pulse; low blood pressure in the upright position; headache; nausea; dizziness; "goose bumps"; and general weakness.

During sustained physical activity by aerobically fit men and women, metabolic rate often increases __________ times above the resting level.

The body absorbs radian heat energy when the temperature of objects in the environment exceeds skin temperature.

Factors other than air temperature that determine the physiologic strain imposed by heat include body size and fatness, level of training, acclimatization, adequacy of hydration, and external factors.

Heat stress initiates hormonal adjustments to enhance the loss of salts and fluid in sweat over a prolonged period of time.

Hyperhydration before physical activity in a hot environment protects against heat stress because it fosters the following.

Fluid lost during thermoregulation often creates a relative state of __________.

Heat cramps are the most serious and complex heat-stress malady and requires immediate medical attention.

Not a urine characteristic of well-hydrated individuals?

Represents the best clothing choice for participating in physical activity in hot temperatures?

During physical activity in hot weather, competition exists between mechanisms that __________.

The rate of conductive heat loss depends on the temperature gradient between the skin and surrounding surfaces and their thermal qualities.

Does not associate with progressive dehydration.

The risk for dehydration __________ during vigorous cold-weather physical activity.

Strictly following an adequate water replacement schedule reduces the risk of dehydration and its consequences, particularly hyperthermia.

A moderate workout generally produces a __________ sweat loss over a 1-hour period.

Occurs when body temperature increases by 5°C or more.