When the temperatures get cooler, you have to know how to adapt your equipment!
But beyond the purely psychological aspect, can we experience particular effects linked to low temperatures, and what dangers and pitfalls should we avoid when we want to run or cycle outside at 3°C? We'll tell you everything about practicing outdoor sports in cold weather!
Note that it's essential to listen to yourself and respect your own rhythm. If the temperature is too cold, it's best not to force yourself and to favor indoor activities. And if you have heart, vascular, or lung problems, consult your doctor before starting.
What influence will the cold have on our body?
Some will say "even at -1°C, when I do sport I feel hot!". 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 sports practice, mentioned in a previous article (intensification of cardio or breathing, use of nutrients, etc.) remain. But other mechanisms are added and increase energy expenditure, already significant during physical exercise:
Thermoregulation: This represents the set of physiological processes implemented by the body to maintain its internal temperature around 37°C, regardless of the external temperature or metabolic level. This regulation is based on a constant balance 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, skeletal muscles and the central nervous system. In optimal conditions, the core temperature is 37°C, the reference temperature around which enzymatic reactions and the activation of the main intracellular mechanisms occur.
The outer parts of the core, 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.
Humans exchange heat with the environment using 4 methods: by convection (exchanges between the skin and an ambient fluid or gas – principle of cryotherapy), by conduction (exchanges between the skin and an object in direct contact that would have a different temperature: e.g. hot water bottle or ice cube), by radiation (the skin gives off heat in the form of radiation) and by evaporation (sweating). This phenomenon occurs continuously, not only during a run or a bike ride, but intensifies during physical activity and even more so when climatic conditions are extreme (cold or hot).
Increased thermogenesis: the first thermal response to cold
Thermogenesis is the production of heat by the body through increased cellular metabolism. Two systems are activated in this state:
- Activation of cellular metabolism , particularly in fatty tissue from brown fat. The only problem is that an adult has very little brown fat. This mechanism is therefore insufficient to provide a correct adaptive response and warm the body. However, this chemical thermogenesis causes an acceleration of metabolism induced by the secretion of adrenaline, glucagon, glucocorticoids and thyroid hormones (over a long-term adaptation).
- Increased muscle tone 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, particularly in the jaw and during inspiration.
Vasoconstriction
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 heat on the core of the body. On this occasion, blood flow is greatly 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 therefore avoid cooling of the critical zone, and to reduce skin temperature to avoid heat loss.
Vasoconstriction primarily affects the hands and feet in cold weather. Small blood vessels constrict and blood circulation decreases, reducing the supply of oxygen, nutrients, and heat to these extremities. Some people are even particularly susceptible 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 "goosebumps" or the famous expression "to have hairs standing on end." In reality, it's not an expression: the hairs are erect! This physiological mechanism aims to keep a layer of air trapped between the hairs and the skin to insulate against the cold. This reflex was quite useful to our distant ancestors who were particularly hairy, but for modern humans with their short, short hairs, it is no longer of much use. We observe the same phenomenon in animals like cats and birds, but it is still much more useful to them given the thickness of their fleece!
The brain, a true control tower for regulatory pathways
Everything happens in the hypothalamus, a part of the central nervous system located in the heart of the brain. This area contains thermoreceptors that record the temperature of the central nucleus, as well as those of the skin and spinal cord. If these receptors detect a change in temperature, they activate thermal regulation mechanisms. For example, when it's cold, their stimulation causes cutaneous vasoconstriction and heat production.
Peripheral receptors (under the skin, near blood capillaries) and central receptors (wall of intra-abdominal organs, large venous trunks, spinal cord) transmit information about temperature variation to the hypothalamus via a nerve impulse. If the blood supplying the hypothalamus varies by 1°C, this is enough to cause thermogenesis or thermolysis (heat removal). Note that we have more thermoreceptors sensitive to cold than to heat, especially on the face.
What are the dangers of outdoor sports in cold weather?
Of course, there's no question of stopping outdoor sports when it's biting, otherwise winter sports would be the Hunger Games! However, it's necessary to distinguish between sports practice in a cold but dry environment (airborne cold) and in a cold aquatic environment, a small nuance that is very important. You can indeed move around in a freezing airborne environment by adapting your clothing, however, water being an excellent thermal conductor, the body cools down 25 times faster in an aquatic environment.
It's also important to highlight the nuance between perceived temperature and actual temperature. The perceived temperature is determined by wind speed, known as the "wind-chill" factor. With clothing that doesn't provide enough protection, heat production during the activity may be insufficient to counteract the effects of temperature coupled with wind. For example, skiing at -1°C with a 30km/h wind is the same as skiing at -15°C, increasing the risk of hypothermia and frostbite.
It is therefore necessary to adapt to the conditions to avoid several risky situations. We have stated above the mechanisms that allow the organs and the central nervous system to stay warm. However, in the event of intense or prolonged cold, unsuitable equipment, or in unanticipated extreme situations, the body's core temperature can still drop... And below a certain threshold, it's a disaster. Here are the situations to prevent and avoid to avoid putting yourself in danger:
First up, hypothermia ! Hypothermia, the primary enemy of outdoor athletes in cold weather, is a decrease in core body temperature. If it falls below 35°C, a cascade of reactions takes place, and believe it or not, they're not pleasant.
It can have different effects and consequences depending on the stage:
- Mild (36°C to 32°C) / Defense phase: You will then feel severe chills (or even teeth chattering), pale skin, painful extremities, goosebumps, an increased heart rate, the need to urinate, difficulty breathing and a feeling of cold. To alleviate this condition, you must move a lot, put on a survival blanket or warm, dry clothing, eat, drink warm or hot drinks and shelter from any wind.
- Moderate (from 32°C to 30°C) / Exhaustion phase: We no longer shiver but rather tremble, we feel a certain well-being and our heart rate decreases, we slowly slide into a state of decreased alertness and altered state of consciousness, likely to evolve into a coma. It is then advisable not to reheat too quickly or rub, not to move too suddenly. It is necessary to reheat slowly and notify emergency services.
- Severe (less than 28-30°C) / Paralysis phase: You then enter a coma, with a slowdown in vital functions. This is a life-threatening emergency that must be treated by specialized doctors.
Note that the stages of hypothermia vary slightly depending on the source, but it should never be ignored and represents a real risk that must be taken into account during and after use.
Muscle injuries : Of course, regardless of the weather and temperature, muscle injury remains a risk during a sports session or training. But since the cold reduces the oxygen supply to the muscles (by constricting the blood vessels), they will be less supplied and could therefore potentially break more quickly. It is therefore essential, in cold weather, to warm up gradually to prepare the muscles for the effort and raise the body temperature slowly. Perform your warm-up indoors before going out into the elements.
Cold bites : Poorly covered or overly exposed to the cold, your extremities, ears, lips and the tip of your nose can be victims of cold bites: chapping, cracks or even chilblains or frostbite (more serious). The cause: the cold, poor circulation and dry skin, which, combined, can lead to this type of very unpleasant and often painful lesion. Nail bites (painful numbness that takes a long time to warm up) can also be accompanied by nausea.
Breathing difficulties : Asthmatic athletes, beware! While dry cold poses no danger to your lungs, damp 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 before reaching your lungs!
Dehydration and hunger : The sensation of thirst diminishes in cold weather, or even disappears altogether. But breathing in cold air and maintaining your internal temperature are dehydrating processes, so it's essential to stay hydrated before, during, and after exercising.
It is also essential to increase your calorie intake because the energy loss will be greater. Remember to bring your favorite Holyfat , which will provide you with 280kcal per pouch and will allow you to have enough energy to go further, without feeling sluggish . In addition, digestion releases heat. Holyfat is particularly easy to digest and quickly assimilated, to avoid any small digestive problems during your session.
How to equip yourself properly in cold weather to go further?
For your outdoor activities, choose suitable clothing that provides comfort while avoiding the sauna effect. It is essential not to remain in excessive humidity; humidity is conductive, and the body will cool down more quickly (especially after exercise). If the environment is cold and windy, this can increase the risks. Remember the 3-layer rule for the upper body:
- Choose protective underwear : close-fitting, it will absorb moisture and wick away perspiration during exercise (synthetic rather than cotton to avoid retaining moisture).
- A second layer of insulating clothing : it must retain heat so as not to let your body cool down. It must be breathable (fleece jacket or sweater, GoreTex or Aquastop fabrics – avoid wool, which is heavier and less breathable).
- Waterproof clothing (avoid classic windbreakers which do not protect against bad weather in case of rain or snow)
For the bottom, you can opt for special breathable cold pants or long underwear.
It is also essential to cover your head, hands, neck and feet well . Always in breathable material, opt for sports gloves and a pair of socks with good insulating quality. Do not layer socks, they would compress the foot too much and prevent good circulation, in addition to causing friction. For the head, a breathable cap to cover the gourd and ears is ideal.
Finally, after exercising, warm up and hydrate yourself: hot drink, meal, rest. Finish your workout preferably near your home or vehicle so as not to be exposed to the cold for long periods without activity and in wet clothes, and bring a dry change of clothes if you cannot shower quickly (underwear included!). Don't forget to stretch and possibly take a warm bath to warm up gently.
Cold, a health ally when used correctly
The therapeutic use of cold dates back to ancient times. In Europe, legend attributes its first use to Hippocrates. In the Nordic countries, as early as the Viking Age, winter bathing in iced water or snow was practiced, to which therapeutic properties were attributed. In some countries, such as Finland, many residents continue this tradition and bathe in iced water in winter to maintain good health. This practice is credited with reducing respiratory ailments, joint pain related to rheumatism, improving recovery, and a feeling of general well-being.
Medical cryotherapy was developed in Japan in the 1970s to treat pain, initially related to rheumatism and then post-traumatic, by exposing the body to temperatures ranging from -140°C to -110°C. Its use for athletes followed shortly afterward. Today, several methods exist that offer athletes the opportunity to combat fatigue and muscle pain through total or partial immersion in intense cold.
From a medical perspective, cryotherapy could potentially have many indications, and it appears that cold has positive effects in certain situations. That being said, the benefits remain subjective, and some medium- or long-term adverse effects have been noted. The scientific community acknowledges that it lacks perspective on this practice and its real benefits; the treatment remains experimental at present. A 2019 INSERM study revealed that cryotherapy had very few proven beneficial effects but many real side effects (burns, chronic cold urticaria, headaches, etc.) 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 or reimbursed by health insurance in France.
It is therefore essential to be well informed before considering it and to opt for a technique adapted to the desired effects, taking into account the contraindications in force (asthma, cardiac or vascular pathology, neurological, skin lesions, etc.).
Don't 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 zooms on our ingredients ... With a bonus of some tips and advice for your preparation and your sports outings (or your busy days).