Heat training

- The normal human body temperature is 37C

- Thermoregulation is the process that allows the body to maintain core temperature 

- Thermorecptors detect changes in temperature and cause vasodilation of arterioles to the skin.

- Some athletes lose 3+ liters of sweat per hour in hot conditions 

- This leads to dehydration which will impair performance 

- 1% drop in body weight, can cause a 10-15% reduction in performance (1kg = 1 litre)

- The amount of sweat is affected by humidity 

- Low humidity increases sweating 

- High humidity decreases sweating and the cooling process.

' Cardiovascular drift is the potential side effect of exercise in a hot climate'

- This leads to an increase in HR during sub-maximal exercise.

- A 1-degree rise in temperature will cause an upward drift of HR by 10 bpm

- Redirection of blood flow to the skin reduces blood flow to the muscles and venous return 

- Fluid loss & therefore blood plasma through sweating results in increased blood viscosity 

- As a result stroke volume decreases, causing HR to increase to maintain cardiac output.

• Dilation of the arterioles and capillaries to the skin, to increase blood flow and blood pooling

• Decreased blood plasma volume, venous return, SV, Q, and blood pressure leads to;

           - Increased HR & strain on the cardiovascular system

           - Reduced O2 to working muscles 

          - Earlier fatigue 

          - Dehydration 

• Drying of airways leads to; 

    - Increased mucus production 

    - Constriction of airway

    - Decreased volume of gas exchange