1. Exercise in the Heat Learning Objectives
To understand how the heat affects our body.
To understand hyperthermia and cardiovascular drift.
To be able to explain the effects that exercising in the heat has on performance.

3. Effects of the heat on our body
What is normal body temperature?
How much does it rise/ fall in a day?
What is thermoregulation?
What receptors detect change in temperature?
What happens if core temperature rises?
What bodily function removes heat from our body?
What happens if fluids lost during exercise are not replaced?

4. Effects of the heat on our body
What is normal body temperature? 37c
How much does it rise/ fall in a day? 1c
What is thermoregulation? The process of maintaining internal core temperature.
What receptors detect change in temperature? Thermoreceptors.
What happens if core temperature rises? Heat is transported to the skin by the blood and is released through convection and evaporation.
What bodily function removes heat from our body? Sweating.
What happens if fluids lost during exercise are not replaced? Dehydration.

5. Effects on our body
Dehydration – loss of water in body tissues. Impairs the body’s ability to thermoregulate and core temperature will rise. A rise in core body temperature of several degrees can affect physical performance and, if unlimited, can cause an athlete to enter hyperthermia. This is common if athlete’s push themselves too fast, for too long in too hot, humid conditions.

6. Increase in core body temperature
Caused by:
High and prolonged exercise intensities
High air temperatures
High relative humidity

7. Cardiovascular drift
During prolonged exercise in the heat, the increased rate of muscular contraction and chemical reactions produce metabolic heat.
This may not be removed from the body quickly enough to maintain core body temperature.
This cause cardiovascular drift – an upward drift in heart rate associated with a rise in body temperature.
1c increase HR by 10bpm.
The redirection of blood flow to the skin for cooling limits blood flow to the muscles and venous return.
Rising core temperature alters the function of the protein molecules, such as enzymes and receptors, and affects the rate of chemical reactions.

9. The effects on the body CV system
Dilation of arterioles and capillaries to the skin
Increased blood flow and blood pooling in the limbs
Decreased blood volume, venous return, stroke volume, cardiac output and blood pressure
Leading to increased heart rate to compensate
Increased strain on the CV system
Reduced oxygen transport to the working muscles

10. The effects on the body Respiratory system
Dehydration and drying of the airways in temperatures above 32c makes breathing difficult
Leading to increased mucus production
Constriction of the airways
Decreased volume of air for gaseous exchange
Increased breathing frequency to maintain oxygen consumption
Leading to increased oxygen cost of exercise
High levels of sunlight increase the effects of pollutants in the air
Causing irritation of the airways, leading to coughing, wheezing or asthma symptoms

11. The overall effects Missing words Duration endurance Thermal Fatigue
Glycogen
Hydrated
Accumulates
Decreasing
Anaerobic
Production
asthma

12. Effects on performance
Read the photocopied sheet and do the following tasks:
TRANSFORM one bullet point from how to minimise a decrease in performance for pre, during and post competition into an image. NO WORDS ALLOWED.
REDUCE each paragraph on ‘effect on performance’ into 2 bullet points. 12 words maximum for each point.E
PRIORITISE the 3 most important ways of minimising the decrease in performance.
Rank them 1-3 and briefly explain number 1
EXTEND
Compare the effects of exercising in the heat on the body, with the effects of being at altitude. What are the similarities and differences.

13. How to reduce the effects?
Pre-competition

14. How to reduce the effects?
During competition

15. How to reduce the effects?
Post-competition