Exercise Physiology: Heat + Cold

The body adapts to training in excessive heat. Which statements (multiple answers) discuss correct adaptations to heat training:

• Increased sweat production - most effective method of heat loss and very closely linked with the heat transfer method of evaporation

• Increased blood plasma - allows for better blood flow therefore better heat loss in the peripheral vessels. Heart rate also remains lower.

• There is a reduced electrolyte and sodium concentration in sweat - the fitter the athlete the more dilute their sweat.

• Sweating occurs more in places that are covered by clothing so heat loss via evaporation is enhanced

Heat transfer often works on a gradient basis. This means that heat

• Flows to areas which are hotter

• Flows to areas which are cooler

• produced by the body only moves if exercising in hot environments

• will simply build up in the body until exercise stops

Regarding cardiac drift, select the correct statement

• It is an immediate response which occurs when exercising in heat

• It involves an increased heart rate to compensate for a reduced stroke volume. This enables a maintenance of cardiac output.

• It involves an stroke volume to compensate for a reduced heart rate. This enables a maintenance of cardiac output.

• It involves an increased heart rate to compensate for a reduced stroke volume. This enables a maintenance of tidal volume

Regarding double heat load, select the INCORRECT statement

• Double heat load is the decreased blood flow to both the working muscles and the skin.

• It comes about because in heat, the competition between muscles and skin for blood is intensified

• Is not exacerbated (intensified) when exercising in extremely hot conditions

• Double heat load discusses both the heat which is absorbed from the environment and the heat generated by working muscles.

Which is NOT a physiological adaption which results from heat acclimatisation training

• Increased sweat rate (you sweat more)

• Reduced core temp at onset of sweating (you sweat sooner)

• You sweat in more efficient places (where it can be best evaporated)

• There is an increased amount of haemoglobin in the blood (increases the oxygen carrying capacity of the blood)

Which of the below is NOT a short term response to exercising in heat

• Increased sweat response

• Vasoconstriction of the blood vessels in the skin

• Increase blood flow to the periphery

• •Increased core and skin temp

Vasodilation of the blood vessels near the skin help heat to be transferred away from the body via which method:

• Conduction

• Convection

• Radiation

• Evaporation

Hyponatremia refers to:

• Overheating and occurs when body experiences extreme loss of salt and water through sweating

• An abnormally low concentration of salt in the plasma.

• when fluid intake does not match fluid loss

Sweat rates are highest in _______ environments because the functionality of ________ is impaired. In these situations, the body response by producing _____ sweat.

• hot and humid / evaporation/ less

• hot and windy / convection/ less

• hot and windy / convection/ more

• hot and humid / evaporation/ more

MULTIPLE ANSWERS: To better cope with heat athletes can:

• Undertake pre-cooling methods such as drinking ice slushies or wearing ice vests

• Wear light, tight fitting clothing

• Ensure they increase their fat intake to have a better body composition which will insulate their bodies.

• Wear light, loose fitting clothing