La pratique sportive par temps froid : bienfaits et dangers | Holyfat

Sports in cold weather: benefits and dangers

When the temperatures get colder, you have to adapt your equipment!

But beyond the purely psychological aspect, can you feel particular effects linked to low temperatures, what dangers and pitfalls should you avoid when you want to run or ride outside in 3°C weather? We will tell you everything about outdoor sports in cold weather!

Note that it is essential to listen to yourself and respect your rhythm, if the temperature is too cold, it is preferable not to force yourself and prefer indoor activities. And if you have heart, vascular or pulmonary problems, consult your doctor before you start.

What influence does the cold have on our body?

Some people will say "even at -1°C, I feel hot when I do sports". Certainly my good friends, because the body is an extraordinary machine that knows how to adapt. To maintain its homeostasis (its general balance), it will implement several endogenous thermoregulatory mechanisms. Of course, all the physiological adaptations inherent to the practice of sports, mentioned in a previous article (intensification of cardio or breathing, use of nutrients, ...) remain. But other mechanisms are added and increase the energy expenditure, already important during a physical exercise:

Thermoregulation: It represents all the physiological processes set up by the body to maintain its internal temperature around 37°C, regardless of the outside temperature or metabolic level. This regulation is based on a constant equilibrium based on heat input and loss. This temperature constancy does not apply to all parts of the body but only to the center, called the "core", which includes the thoracic and abdominal viscera, the skeletal muscles and the central nervous system. Under optimal conditions, the temperature in the nucleus is 37°C, the reference temperature around which enzymatic reactions and the activation of the main intracellular mechanisms occur.

The external parts of the nucleus, consisting of the skin and subcutaneous tissues, can have a variable temperature (from 10°C to 40°C depending on external conditions). Finally, the vascular system allows rapid exchanges of energy and temperature to maintain homeothermy. Maintaining a constant core temperature is only possible through thermoregulation, which represents the balance between the amount of heat lost and produced or received.

Man exchanges heat with the environment in 4 ways: by convection (exchanges between the skin and a fluid or an ambient gas - principle of cryotherapy), by conduction (exchanges between the skin and an object in direct contact which would have a different temperature: ex hot water bottle or ice cube), by radiation (the skin gives off heat in the form of radiation) and by evaporation (sweating). This phenomenon takes place constantly, not only during a run or a bike ride, but intensifies during physical activity and even more so when the climatic conditions are extreme (cold or hot).

The increase in thermogenesis: the first thermal response to cold

Thermogenesis is the production of heat by the body through increased cellular metabolism. Two systems are involved in this state:

  • Activation of cellular metabolism, particularly in fatty tissue from brown fat. The only problem: an adult has very little brown fat. This mechanism is therefore insufficient to provide a correct adaptive response and warm up the body. Nevertheless, this chemical thermogenesis causes an acceleration of the metabolism induced by the secretion of adrenalin, glucagon, glucocorticoids and thyroid hormones (on a long term adaptation).
  • Increase in muscle tone which causes muscle shivering: the contractions of the fibers will be desynchronized but the movement is unconscious. If it intensifies, it can become conscious and even rather unpleasant, in particular at the level of the jaw and inspiration.


Cutaneous vasoconstriction: Under the effect of cold, peripheral circulation will be reduced by a phenomenon of contraction of the vessels and closure of certain vascular circuits in order to maintain the heat on the core of the body. On this occasion, the blood flow is strongly reduced (from 20mL/min to 1mL/min. This reaction has two objectives: to limit exchanges between the body core and other areas of the body and thus avoid cooling of the critical area, and to decrease skin temperature to avoid heat loss.

Vasoconstriction occurs primarily in the hands and feet when it is cold. The small vessels contract and blood circulation decreases, thus reducing the supply of oxygen, nutrients and heat to these extremities. Some people are even particularly sensitive if they have Raynaud's syndrome and can develop painful swelling or easily develop frostbite.

Horripilation, nothing to do with the effect your mother-in-law has on your nerves...

Horripilation is better known as "goose bumps" or the famous expression "getting hairy". In reality, it's not an expression: the hairs are erect! The purpose of this physiological mechanism is to keep a layer of air between the hairs and the skin to insulate from the cold. This reflex was quite useful to our distant and particularly hairy ancestor, but for modern man with his short hairs it is no longer of much use. We observe the same phenomenon in animals such as cats or birds, but it is still much more useful to them given the thickness of their fleece!

The brain, the control tower of regulatory pathways

Everything happens in the hypothalamus, a part of the central nervous system located in the heart of the brain. In this area are the thermoreceptors that register the temperature of the central nucleus, but also those of the skin and the spinal cord. If these receptors detect a temperature variation, they activate the thermal regulation mechanisms. For example, when it is cold, their stimulation leads to cutaneous vasoconstriction and the production of heat.

Peripheral receptors (under the skin, near the blood capillaries) and central receptors (walls of intra-abdominal organs, large venous trunks, spinal cord) transmit the temperature variation information to the hypothalamus via a nerve impulse. If the blood flowing to the hypothalamus varies by 1°C, this is enough to trigger thermogenesis or thermolysis (heat evacuation). Note that we have more thermoreceptors sensitive to cold than to heat, especially on the face.

What about the danger of outdoor sports in cold weather?

Of course, there is no question of stopping outdoor sports when it's cold, otherwise winter sports would be the Hunger Games! However, it is necessary to distinguish between sports in a cold but dry environment (cold air) and in a cold water environment, a small nuance that is very important. One can indeed evolve in an icy air environment by adapting one's clothing, on the other hand water being an excellent thermal conductor, the body cools down 25 times faster in an aquatic environment.

It is also important to underline the difference between the temperature you feel and the actual temperature. The temperature felt is determined by the wind speed, called the "wind-chill" factor. With clothing that does not provide sufficient protection, heat production during the activity may be insufficient to counter the effects of the temperature coupled with the wind. For example, skiing at -1°C with a 30km/h wind is the same as skiing at -15°C, thus increasing the risk of hypothermia and frostbite.

It is therefore necessary to adapt to the conditions to avoid several risky situations. We have outlined above the mechanisms that allow the organs and the central nervous system to stay warm. However, in the event of intense or prolonged cold, inappropriate equipment or in extreme situations that are not anticipated, the temperature of the body core can still drop... And below a certain threshold, it is a tragedy. Here are the situations to prevent and avoid in order not to put yourself in danger:

First of all,hypothermia ! The first enemy of the outdoor sportsman in cold weather, hypothermia is the decrease of the core temperature of the body. If the core temperature drops below 35°C, a cascade of reactions takes place, and believe me, they are not pretty.

It can have different effects and consequences depending on the stage:

  • Mild (from 36°C to 32°C) / Defense phase: This is when you experience severe shivering (even teeth chattering), pale skin, sore extremities, goose bumps, an increased heart rate, the urge to urinate, difficulty breathing and a feeling of cold. To overcome this condition, you must move around a lot, put on a survival blanket or a warm and dry garment, eat, drink warm or hot water, and take shelter from the wind if necessary.
  • Moderate (from 32°C to 30°C) / Exhaustion phase: You no longer shiver but rather tremble, you feel a certain well-being and your heart rate decreases, you slowly slide towards a state of decreased vigilance and altered state of consciousness, likely to evolve towards a coma. It is then advisable not to warm up too quickly or rub, not to move too suddenly. It is necessary to warm up slowly and to warn the help.
  • Severe (less than 28-30°C) / Paralysis phase: One enters into a coma, with a slowing down of the vital functions. This is a life-threatening emergency that must be treated by specialized physicians.

Note that the stages of hypothermia differ slightly according to the sources, but that it should never be ignored and represents a real risk to which it is necessary to be attentive during and after its practice.

Muscular injuries: Of course, regardless of the weather and temperature, muscular injury remains a risk during a sports session or training. But the cold reduces the supply of oxygen to the muscles (by contracting the blood vessels), the latter will be less nourished and can then potentially rupture more quickly. It is therefore essential, in cold weather, to warm up gradually in order to prepare the muscle for the effort and to raise the body temperature slowly. Warm up indoors before heading out into the elements.

Cold bites: Poorly covered or too exposed to the cold, your extremities, ears, lips and the tip of your nose can fall victim to cold bites: chapping, cracks, frostbite or frostbite (more serious). The cause: the cold, poor circulation and skin dryness, which, combined, can lead to this kind of unpleasant and often painful lesions. The nails (painful numbness very long to warm up) can also be accompanied by nausea.

Breathing difficulties: Asthmatic athletes, beware! If a dry cold is not dangerous for your lungs, a wet cold is a contraindication to outdoor physical activity. And for all athletes: remember to breathe through your nose rather than your mouth. This way, the air will be warmed up before reaching your lungs!

Dehydration and hunger: The sensation of thirst diminishes when it is cold, or even disappears. But breathing in cold air and maintaining your internal temperature are dehydrating processes, so it is essential to stay well hydrated before, during and after sports.

It is also essential to increase your caloric intake because the energy loss will be more important. Think of bringing your favorite Holyfat, which will bring you 280kcal per pouch and will allow you to have enough energy to go further and further, without slackening. Moreover, digestion releases heat. Holyfat is particularly easy to digest and quickly assimilated, to avoid any small digestive problem during your session.

How to equip yourself in cold weather to go further?

For your outdoor practice, choose adapted clothes, giving you a certain comfort while avoiding the sauna effect. It is essential not to stay in a high humidity, as humidity is conductive and the body will cool down more quickly (especially after practice). If the environment is cold and windy, this can increase the risks. Remember the 3 layer rule for the upper body:

  • Choose a protective undergarment: close to the body, it will absorb moisture and wick away perspiration during exercise (synthetic rather than cotton to avoid retaining moisture).
  • An insulating garment as a second layer: it must retain heat so that your body does not get cold. It must be breathable (fleece jacket or sweater, GoreTex or Aquastop fabrics - avoid wool, which is heavier and less breathable).
  • A waterproof garment (avoid classic windbreakers that do not protect you from bad weather in case of rain or snow)

For the bottom, you can opt for special cold breathable pants or long johns.

It is also essential to cover your head, hands, neck and feet. Always in breathable material, opt for sports gloves and a pair of socks with good insulating quality. Do not wear overlapping socks, as they would compress the foot too much and prevent good circulation, in addition to causing chafing. For the head, a breathable cap to cover the calabash and the ears is ideal.

Finally, after the sport, warm up and hydrate yourself: hot drink, meal, rest. Finish the effort preferably near your home or your vehicle so as not to remain exposed to the cold for a long time without activity and in wet clothes, and provide a dry change of clothes if you can't shower quickly (underwear included!). Don't forget to stretch and eventually take a hot bath to warm up gently.

Cold, a health ally when used properly

The therapeutic use of cold goes back to ancient times. In Europe, legend attributes its first use to Hippocrates. In the Nordic countries, as early as the time of the Vikings, winter bathing in ice water or snow was practiced and was said to have therapeutic properties. In some countries, such as Finland, many people continue this tradition and bathe in icy water in winter to stay healthy. This practice is credited with reducing respiratory ailments, joint pain related to rheumatism, better recovery and a general feeling of well-being.

Medical cryotherapy began in Japan in the 1970s to treat pain, initially related to rheumatism and then post-traumatic pain, by exposing the body to temperatures ranging from -140°C to -110°C. Its use for sportsmen came in the wake. Today, several methods exist and offer athletes the opportunity to fight against their fatigue and muscular pain through total or partial immersion in intense cold.

From a medical point of view, cryotherapy could potentially have many indications and it seems that cold has positive effects in certain situations. That being said, the benefits remain subjective and certain undesirable effects in the medium or long term have been noted. The scientific community recognizes that it lacks hindsight on this practice and its real impact, and that the treatment remains experimental at the present time. An INSERM study revealed in 2019 that cryotherapy had very few proven beneficial effects but many real side effects (burns, chronic cold urticaria, headaches...) when used in the context of inflammatory or neurological diseases or sometimes outside of any pathological context. This technique is not recognized as a treatment nor is it reimbursed in France by the health insurance.

It is therefore essential to be well informed before considering it and to choose a technique adapted to the desired effects, taking into account the contraindications in force (asthma, cardiac or vascular pathology, neurological, skin lesions, etc.).

Do not hesitate to consult our other articles, in particular "How to avoid fatigue during exercise, especially during endurance sports","What is a hypoglycemic attack", "Is the ketogenic diet suitable for athletes" as well as our focus on our ingredients... With the added bonus of some tips and advice for your preparation and your sports outings (or your busy days).

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