At low temperatures, several reactions occur in the body, and unfortunately, they are not always safe for humans. What is important to know so that the onset of cold weather does not become a stress for the body?
The arrival of winter, the first snow, walks, and winter photo shoots – emotions go wild. But there is another side of the coin: with the advent of cold weather, there is a risk of hypothermia. And it is a mistake to assume that this requires a decent sub-zero temperature. The danger arises even at temperatures from 0°C to -7°C.
We are accustomed to the idea that our body is an automated system that can withstand adverse factors. But it turns out that the possibilities are limited due to the peculiarities of the physiology of internal systems. And a person can protect himself from low temperatures only with the help of clothing or housing. Otherwise, changes in the body under the influence of cold are inevitable.
Physiological reactions to cold – what happens in the body
To preserve heat during freezing, the body reacts by reducing heat transfer to the external environment and increasing heat production to heat the vital internal organs. The reaction is a spasm of blood vessels on the surface of the skin and a reduction in blood flow to it. Many have noticed how the opening of the body begins to turn white.
But since, with the cessation of blood flow, the tissues are deprived of oxygen and nutrition; such a reaction is permissible only for a limited time. Therefore, the body triggers peripheral vasomotor reactions, which leads to the launch of thermoregulation: vasoconstriction is replaced by their expansion – the body area turns red. As a result, oxygen begins to flow back to the skin.
But the above reaction is short-lived, and if a person is still cold, there is a reflex increase in blood pressure and heart rate. By the way, the strength of the reaction depends on the specific area: cooling the body or hand affects the state of the body to a lesser extent than hypothermia of the face. However, prolonged or intense exposure to cold leads to a slowing heart rate, blood circulation slows down, and pressure drops; a person in this condition already needs medical help.
Why does the incidence increase with the onset of cold weather? It turns out that a cold snap also affects the immune system; the number of lymphocytes and immunoglobulins decreases. In addition, during the cold season, the level of melatonin, a hormone that affects the immune system, drops, and with its deficiency, pronounced immunosuppression occurs. Also, during the research, it was found that melatonin can stimulate immunity cells, whose function is to fight viruses.
With the advent of cold weather, the situation is aggravated by the crowding of people, which occurs in autumn and winter in labor collectives. It only takes one person with a cold, and infection is highly likely. And first of all, a person with hypothermia, whose immunity is already weakened, will be hit.
Under hypothermia conditions, one of the body’s reactions is also an increase in pulmonary ventilation, depth, and frequency of respiration. This leads to increased oxygen consumption and heat production. However, at the same time, heat losses increase – when the inhaled cold air is warmed. If a person is still exposed to cold, then due to prolonged hypothermia, pulmonary ventilation decreases oxygen consumption drops. It is not excluded from the development of cold hypoxia due to oxygen deficiency in the body.
However, negative reactions begin even when cold air is inhaled. To warm it up, the liquid is secreted in the nasal mucosa – everyone noticed that it “flows” from the nose in the cold. But at the same time, the mucous membrane of the nasal cavity, losing moisture, dries up and ceases to fulfill its protective function; bacteria and viruses easily penetrate the body.
A decrease in immunity due to hypothermia leads to the fact that the pathogenic microflora, which is not dangerous for the body in its normal state, is activated. This can cause the development of cystitis, pyelonephritis, prostatitis, etc. In addition, cold contributes to an increase in urine produced in the body. With a long stay in the cold, a person may be at risk of dehydration.
Due to the cold, the breakdown of animal fats in the body worsens, which contributes to an increase in cholesterol levels. By the way, among the properties of melatonin is the prevention of the formation of cholesterol plaques in the vessels, but due to a decrease in its amount with the onset of cold weather, the risk of vascular damage by atherosclerosis increases. In addition, it has been noticed that gastrointestinal disease exacerbations increase in the off-season.
Skin and hair
Narrowing of the vessels on the periphery limits the blood flow to the scalp, the deterioration of blood circulation affects the nutrition of the hair roots, and they become dull, brittle, and prone to falling out. The surface of the body’s skin also becomes dry, becomes unhealthy, and the nails lose their strength and exfoliate.
Mood and sleep
Why does sleep disturbance often accompany the off-season? The same melatonin may be the cause – its main function is to regulate sleep and wakefulness. If the production of melatonin is disturbed, the body receives information about the end of sleep, insomnia occurs, and a feeling of weakness in the morning. A person experiencing sleep problems is prone to mood swings and often develops a depressive state. However, with the decrease in daylight hours, which occurs in autumn, melatonin levels may initially remain the same, which causes daytime sleepiness.
Also, a factor affecting mood is a deficiency of the active form of vitamin D3, produced in the human body under the influence of sunlight. As daylight hours get shorter, there are fewer sunny days, and vitamin D3 deficiency appears. As a result, mood swings, constant fatigue, etc.
What to do to neutralize the effect of cold temperatures
- Clothing for the season – rule number 1. It is important to abandon tight things that restrict movement; squeezing impairs blood circulation. It is better if there is a layer of air between the layers of clothing that retains heat. Remember your hat and mittens.
- Full sleep – at least 7-8 hours – is one of the conditions for good health. You must go to bed by 23 hours to restore melatonin production. It is believed that night-time artificial light sources in the sleeping area suppress the production of the hormone, so you should sleep in the dark.
- Good nutrition with sufficient content of vitamins A, C, and group B – this rule is especially important with the onset of cold weather. In addition, the diet should contain foods with a high content of bioflavonoids, which protect the body from heart diseases and infections, lower cholesterol, strengthen the walls of blood vessels, help maintain healthy hair and nails, etc. Natural sources of substances useful during cold weather are fruits (citrus fruits, peaches, strawberries, etc.) and vegetables (bell peppers, broccoli, spinach, etc.).
What else is important to consider
Cold affects people in different ways. Not the last role is played by the hardening of the body, to a large extent – past diseases, when a person’s immunity is weakened. It has been observed that the effect of cold may also depend on the person’s metabolism and emotional state. By the way, as Canadian psychologists assure, the feeling of cold and the desire to warm up increases with social isolation.
However, factors such as localization and cooling area and the duration of the influence of low temperatures are worth considering. Among the factors that also deserve attention is high humidity. Remember: air temperature is not always a criterion for a cooling effect on the body; for example, frostbite on the feet of soldiers in damp trenches during the First World War, when the main factor was humidity and wet shoes, although the air temperature was above zero. Therefore, in cold weather, you should not cover your nose and mouth with a scarf since you will have to inhale cold air and moist air.
Useful properties of cold
But what about the information that low temperatures can be useful? Of course, there are several useful properties of cold, for example:
- During winter walks, more serotonin is produced – the so-called happiness hormone, which affects mood;
- Metabolism is accelerated, and fat burning is faster because the body needs the energy to warm body;
- When exposed to low temperatures, the amount of adiponectin increases – a protein that has an anti-inflammatory effect, prevents the deposition of fat in the vessels, reduces the risk of blood clots, and normalizes blood sugar levels;
- Short walks are an excellent opportunity to train the adaptive properties of the body, etc.
Of course, similar effects are possible with short-term, controlled exposure to cold when a person is protected by warm clothing.
People tolerate cold in different ways. But if after a walk you can’t warm up for a long time, if you are constantly cold, it may be worth getting an examination. For example, a hypofunction of the thyroid gland can cause constant chilliness. There can be many reasons for circulatory disorders, including atherosclerosis, hypotension, anemia, and vegetovascular dystonia. Make sure that everything is in order with your health, and then the arrival of cold weather, with the first snow, with the feeling of an approaching holiday, and just with walks on frosty evenings will certainly bring a lot of positive emotions.