Sports & Exercise Physiology Flashcards

During exercise in hot, dry conditions, the main mechanism of heat loss is what?

Answer: Evaporation of sweat

Evaporation of sweat accounts for most heat loss during exercise, especially when ambient temperature is high.

Why does high relative humidity increase heat-illness risk during exercise?

Answer: It reduces the evaporation of sweat from the skin

A humid environment reduces the vapor pressure gradient, limiting evaporative cooling.

Which adaptation typically occurs after 10-14 days of heat acclimatization?

Answer: Expanded plasma volume and earlier onset of sweating

Heat acclimatization increases plasma volume, sweats earlier and more, and conserves sodium.

Cardiovascular drift during prolonged exercise in the heat is characterized by what?

Answer: Rising heart rate and falling stroke volume

Fluid loss and skin blood flow reduce stroke volume, so heart rate rises to maintain cardiac output.

At high altitude, the primary cause of reduced aerobic performance is what?

Answer: Lower barometric pressure reducing partial pressure of oxygen

Oxygen remains about 20.9% of air, but lower barometric pressure reduces PO2 and oxygen loading.

Which hormone increases red blood cell production during altitude acclimatization?

Answer: Erythropoietin (EPO)

Hypoxia stimulates the kidneys to release EPO, increasing red blood cell production.

Losing more than about 2% of body mass through sweat during endurance exercise is most associated with what?

Answer: Impaired aerobic performance and higher heart rate

Dehydration beyond roughly 2% body mass can impair endurance performance and raise cardiovascular strain.