Thermoregulation is the process of the body regulating its temperature to maintain healthy systems that function properly in spite of external or internal influences. The body's temperature is comprised 60% of the core body temperature and 40% of the skin temperature. Humans can only withstand 10° drops and 5° rises in body temperature. Ideal human body temperature is considered to be 36.8°C. Maintaining optimal body temperature (even when surrounding temperatures are extreme) is known as thermoregulation and it is controlled by the Hypothalamus which is located within the brain. Thermoregulation is one aspect, among others, of Homeostasis, which is the stability of an organism's internal conditions.
There are a number of ways that thermoregulation occurs, the two most common are:
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Shivering when the body temperature drops.
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Sweating when the body temperature rises.
It is essential to consider the cooling and warming of the body before and after exercise, these tactics may include:
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Wearing appropriate clothing for the climatic conditions.
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Environmental adjustments such as heaters, air conditioners, fans, or open windows allowing ventilation.
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Physical warm-ups.
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Stretching.
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Physical cool-downs (active recovery).
Certain extreme environmental conditions will have adverse effects on the body during exercise and must be taken into consideration when planning sessions.
Exercising in high-temperature and/or humid environments can cause the body to suffer from heat stress. There are two forms of heat stress:
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Heat stress that is able to be compensated through dissipation. The body produces sweat and also distributes blood closer to the skin surface as a means of cooling itself.
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Non-compensable heat stress. The first option is only applicable if the temperature and accompanying exercise remain within a reasonable range and the body can produce enough sweat and/or distribute blood rapidly enough. If not, the body cannot perform properly, dehydration sets in and physical ramifications start occurring such as dizziness, fatigue, weak pulse, muscle cramps, and nausea/vomiting.
Preventative measures to protect against harm when exercising in hot environments include reducing intensity, replenishing fluids and also passively resting if required. Also wearing appropriate clothing, ideally light-weight breathable fabrics.
Exercising in cold-temperature environments can also cause the body to suffer stress. The body attempts to regulate its temperature through the constriction and dilation of blood vessels so that minimal amounts of heat are lost. It also increases heat production by developing muscle tremors (shivering). These adaptions can have an adverse effect on the body, in particular the muscles, if sustained for too long. Some of the effects are:
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Decreased muscle metabolism.
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Decreased oxygen intake.
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Decreased blood flow to the muscles.
Frostbite is a risk when exercising in the cold. Caused by exposing skin to freezing conditions it commonly occurs on the hands (fingers), feet (toes) and also the face (cheeks, ears and nose). Early signs include numbness, loss of feeling and stinging sensations. Ensure that extremities are well covered prior to exercise and if frostbite is suspected then immediately move indoors and seek medical assistance.
When cold temperatures are combined with extreme wind a phenomenon known as wind-chill factor becomes a risk. Wind can penetrate clothing and remove the insulating layer of warm air that surrounds the body. Wind also stirs up dust and dirt particles which can be inhaled or cause damage to eyes.
If the body also becomes wet during cold temperatures then the risk of hypothermia is greatly increased, emergency medical assistance may be required. Symptoms of hypothermia include:
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Intense shivering.
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Slurred speech.
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Loss of coordination.
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Fatigue.
Preventative measures to protect against harm when exercising in cold environments include wearing layers of appropriate clothing, wearing protective eye-wear, eating carbohydrates and replenishing fluids.
When exercising in the high altitude environments the body will not have access to the same oxygen levels than it does at sea level. This will affect endurance style exercises which require oxygen as an energy source.
It isn't so much that there is a lack of oxygen (even at 10,000 feet there is still enough oxygen available for the body's needs) it is the fact that the barometric pressure is less and thus oxygen is not forced into the body (and thus the bloodstream) as easily during the breathing process.
Over time the body can adapt to these environments by developing more red blood cells to help ease the struggle of getting oxygen. However, this method takes time and therefore care must be taken to allow adequate training and preparation prior to attempting exercise in high altitude environments.
Preventative measures to protect against harm when exercising at high altitude include gradual increases in intensity focussing on aerobic training, practicising yoga breathing rhythms (taking deep abdominal breaths), and drinking plenty of water.
