Temperature Regulation In Endurance Athletes: Maintaining Homeostasis In Sportspeople

Maintaining body temperature and homestasis for optimal performance

An endurance athlete has the constant problem of maintaining their body temperature in order to ensure optimal conditions for performance. In many ways we do not take this to be a significant factor for endurance performance however in long events or in extreme weather conditions the ability of the body to maintain homeostasis becomes an issue. Whether it's the Ironman Triathlete suffering with muscle cramps as a result of the external temperature or a polar explorer who has to maintain an adequate body temperature to ward off the effects of hypothermia

Maintaining a balance is the simple equation of keeping an equal level of heat loss and heat production.

Ironman Triathlon places extreme thermoregulatory demands on the body

The Ironman swim- cold water places thermoregulatory demands on the body to maintain homeostasis
The Ironman swim- cold water places thermoregulatory demands on the body to maintain homeostasis | Source

Heat production and heat loss in endurance athletes

Heat Production
Heat Loss
Basal Metabolism effect
Radiation Effect
Muscle Activity
Conduction and Convection
Effect of Body Temperature
Heat Evaporation
Hormonal Effect
Respiration
Adapted from Dick. F W, (2002) Sports Training Principles. 4th Ed. A & C Black

Heat production from your basal metabolism

Your basal metabolic rate is the rate at which your body burns energy while at rest. It is often expressed scientifically in kilocalories per square metre of the body surface per hour and energy release is sufficient only for the functioning of the vital organs of the body. Simple respiration in body tissues creates heat as a waste product as part of the reaction.

Influencing factors include

  • The basal metabolic rate of children is often higher than adults due to their growth needs
  • Fasting and starvation decreases metabolic rate- the body attempts to conserve energy
  • Increased protein intake can actually raise metabolic rate more than fats and carbohydrate due to the need for nitrogen removal from the body to maintain homeostasis.

Muscular activity and heat production

Over 40% of the body's heat production is through muscular activity. Whether at rest or during exercise, Exercise can increase this figure dramatically due to the needs of the body to meet our fuel demands for endurance exercise and ATP/ADP breakdown.

The long distance of an Ironman and exposure to high temperatures puts immense thermoregulatory stress on an athlete
The long distance of an Ironman and exposure to high temperatures puts immense thermoregulatory stress on an athlete | Source

The effect of body temperature

When the body experiences high temperatures it's reaction is to sweat to increase heat loss. This in itself doesn't affect your metabolism greatly, however basal metabolism increases by 7% for every 0.5 Celsius of body temperature elevation which further increases body temperature.

Low temperatures lead to a shivering effect to create additional body temperature.

Consistent exposure to extremes of cold and warmth can lead to conditions of hyperthermia or hypothermia. The body can acclimatise to temperature however persistent exposure increases the risk level.

Hormonal effects on heat production

Hormones can have various effects on the body and heat production. Thyroxine increases your metabolic rate and therefore raises heat production within the body. Your metabolic effect is also raised by the hormones adrenaline and noradrenaline.

The run at the end of a grueling Ironman
The run at the end of a grueling Ironman | Source

Heat loss through radiation

Radiation refers to the transfer of heat from a source to another object. In the case of an athlete this is usually a transfer to objects cooler than the athlete. Athletes lose less heat when the environment and surrounding objects are close to the athlete's temperature.

Heat loss through conduction and convection

Heat can be lost to the air and objects with which the body has contact with- be it clothing, your bicycle. If the athlete moves forward into cooler air like a runner or cyclist would the warmed air is removed away from the body and creates an environment of conduction and convection due to the passage of air over the body's surface.

Athletes should therefore dress accordingly where required to protect them from such currents of air or water in the case of a swimmer which means many triathletes and open water swimmers wear wetsuits. Protection from cold winds is also essential for any athlete.

Ready to start a Triathlon- wetsuits for warmth

Ready to start an Ironman competition- wetsuits help maintain body temperature in cold water environments
Ready to start an Ironman competition- wetsuits help maintain body temperature in cold water environments | Source

Evaporation as a means of heat loss

Sweat is a means of our body losing excess heat. Our body creates large volumes of sweat while we exercise and this increases the rate of heat loss through evaporation as sweat.

Sweat is lost to the air as in conduction and convection as the athlete passes through in cases where the air is dry. Osmolarity differences allow the sweat to transfer into the air and away from the body. However in cases where the humidity level is high the sweat is unable to escape away from the body and heat loss will be severely reduced.

An athlete needs to bear these factors in mind while training and competing to ensure undue stress is not placed on the body.

Heat loss due to respiration

The body loses a very small amount of heat through respiration in the form of water vapour.

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Comments 6 comments

westwoodlaser 4 years ago

Very interesting hub, Thanks for sharing.


CyclingFitness profile image

CyclingFitness 4 years ago from Nottingham UK Author

Thanks for you comment davidheald. While the body can adapt to situations of cold or warmth it has a limited capacity for adaptation to such conditions.

While I have no idea what you actually mean by 'extreme endurance weight training' a sportsperson's training has to be specific to their sport. Why would an extreme version of weight training have more of an effect than training for their sport in situations of stress. Should a cyclist perform an 'extreme' three hours worth of squats to replicate their race length in terms of time or do you have a more specific explanation?


davidheald 4 years ago from Warrington (Cheshire)

It is true that although our bodies are excellent at maintaining a suitable body temperature, the problem is finding the ideal piece clothing to give you that edge when you know your body temp' is going to rise due to competition. The human body produces heat and that's something we cannot get away from so I suppose the only way this will change would be through evolution of the human body. For now the key in my eyes is to continue to condition one's body to perform. Increasing your lactic threshold so that it is easier for the body to perform as this would lead to less of a demand for oxygen uptake and the heart would need beat less. Extreme endurance weight training could condition the body to use muscle more efficiently with less effort thus leading to reduced heat production.


CyclingFitness profile image

CyclingFitness 4 years ago from Nottingham UK Author

Thanks Tribook for you feedback- temperature regulation is paramount to effective sports performance

And thank you Outbound Dan too. In some ways outdoor adventurers are endurance athletes and the weather can provide a huge number of risks to our health


Outbound Dan profile image

Outbound Dan 4 years ago from Niagara Falls, NY

I think that maintaining homeostasis is one of the greatest difficulties that outdoor athletes and adventurers experience. Great useful hub!


tribook profile image

tribook 4 years ago

Great information! It's definitely an important aspect for athletes to consider

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