Physiological Changes in Hot Environments

These flashcards summarize key terms and concepts related to physiological changes and hydration strategies in hot environments for athletes.

What is Dehydration and how can it be caused?

Occurs when the amount of water leaving the body exceeds the amount being taken in.

This can be done through:

• Breathing

• Sweating

• Urination

Double Heat Load

When exercising in the heat the body is forced to deal with two forms of heat

• metabolic heat, created by working muscles

• Enviroment heat in hot conditions

List various physiological changes that an athlete would experience when performing in hot/humid conditions.

• double heat load

• Cardiovascular drift

• dehydration

• Heat exhaustion

• Heart stroke

• hyperthermia

Explain Cardiovascular Drift

Why?

occurs when theres an increase in sweat rate resulting in reduced plasma volume so in order to maintain cardiac output

How?

Heart rate increase relatively smaller than the decrease in stroke volume, so theres a reduced cardiac output which results in less oxygen being sent to working muscles creating a greater strain on the body to maintain exercise levels

Outline the stages of Heat related injuries

Stage 1: Dehydration occurs when fluid replacement does not match fluid loss.

Stage 2: Heat exhaustion occurs when the dehydrated athlete continues to exercise and sweat, thereby losing more fluid. If athletes fail to replace the fluid lost through sweating, they risk moving to stage 3.

Stage 3: Heat stroke occurs when the body stops sweating, resulting in the core temperature rising to dangerous, life-threatening levels caused by a lack of evaporative cooling. It is a form of hyperthermia

Hyperthermia

Elevated body temperature above 38°C due to failed thermoregulation, when the body produces more heat than it dissipates.

Outline hydration techniques that could be used pre, during and post-performance.

Pre

1L before exercise

• 600ml 3-4hrs before the game

• 400ml just before the game to prime the stomach

Allowing athletes to sweat more before performance

During

• Drink ~200ml of water every 15min

Post - replenish back to pre exercise weight

• for every 1L of sweat loss drink 1.5L

Outline the benefits of sports drinks on performance. 

Sport drinks contain carbohydrates, sodium, and potassium

• Provide athletes with rapid supply of high Gi Energy - assit in glycogen sparing

• Replace lost sodium electrolytes - effective in endurance activities (greater than 1hr) where sweat loss is great

• Potassium help maintain electrolyte balance and aid in muscle contractions (help prevent cramps)

Helping maintain fluid levels and rehydrate the athlete