Are temperature changes dangerous for the body

IT IS ACCEPTED THAT WALKING IN THE BATH IS USEFUL, and a contrast shower helps to “harden” the immune system – but at the same time they say that in an unprepared person, diving into cold water can provoke a heart attack. We tried to figure out what science says about the dangers and benefits of temperature changes for the body – does the bath really “remove toxins”, is it useful to leave “warm up” from winter to summer, and whether food with contrasting temperatures can harm.   

Cold and hot shower

A shower with an alternating change in water temperature (from hot to cold and vice versa) is often credited with magical properties: it must strengthen the immune system, train muscles and even regulate the endocrine system. A couple of years ago, a study was conducted in the Netherlands with the participation of three thousand people who took either a regular shower or a contrast shower in the morning. It turned out that the number of days when people were sick (mainly with colds) was the same in all groups, but those who took a contrast shower were 29% less likely to miss work, because they tolerated viral infections much easier. By the way, the timing of the study coincided with the flu epidemic in Holland.   

According to the authors of the study, the mechanisms of such an effect are not yet clear – but it is not associated with the “strengthening” of immunity; it turned out that cold simultaneously induces reactions that enhance and suppress immune function. Possible explanations include psychological expectations (the placebo effect, where a person is confident in healing with a contrast shower) and an improvement in overall fitness. The 29% reduction in absenteeism due to illness is comparable to the effect of physical activity: people who regularly exercised were on sick leave by 35% less than those who did not play sports and did not take a contrast shower. 

The general condition due to temperature contrasts is improved because the cardiovascular system is being trained : under the influence of cold, the superficial vessels are narrowed in order to protect the body from heat loss. In the heat, on the contrary, there is an expansion of the vessels close to the surface of the body – this avoids overheating. As with any workout, this should be taught to the body gradually, starting with mild temperature changes and short intervals. 

Bath and cold water

With scientific evidence of the benefits of a bath, everything is not so simple: on the one hand, saunas and baths are associated with a healthy lifestyle, and a couple of years ago, in another study , it was confirmed that their regular visit correlates with a decrease in the risk of heart disease and even mortality. On the other hand, the official commentary on these results states that people at risk of cardiovascular complications may experience unpleasant sensations in the bath, as a result of which they simply refuse to visit it.  

Another review said that the research mostly involves people who are accustomed to going to the bathhouse since childhood, and there are no control groups. So far, most of the data indicate that baths and saunas do not pose a particular risk for a healthy person and are even useful in terms of improving overall shape; you can go to the bathhouse even with a normal pregnancy. But people with diseases of the heart and blood vessels should be more careful. By the way, the elimination of toxins with sweat is nothing more than a myth: only an insignificant amount of harmful substances can escape through the pores , and the kidneys and liver do an excellent job of detoxifying the body.    

As for a sharp immersion in cold water or a snowdrift immediately after the steam room, scientists insist that it is life-threatening. This also applies to diving on the beach at the beginning of the summer season, when the air is already hot and the water remains cold. In such a situation, the body can develop two opposing reactions: cold shock, which makes the heart beat faster, and the response to diving – it, on the contrary, slows down the heartbeat, trying to conserve oxygen. As a result of the conflict of these reactions, arrhythmia arises, incompatible with life. Therefore, it is very important to enter cold water gradually, allowing the body to adapt.   

Travel from winter to summer

Of course, the long winter is tiring – not only with the cold, but also with the need to wear closed clothes, and the lack of sunlight. Traffic jams due to snow are getting worse, and public transport is cramped due to bulky jackets – in general, solid reasons to fly on vacation to a place where it is hot and sunny. To recharge and relax without putting yourself at risk, there are a few simple rules to keep in mind. 

The main risks of traveling from winter to summer are habitual overheating and sunburn. Often we promise ourselves to lead the healthiest way of life on a trip, but on the very first day after arrival it is better not to start running or playing tennis: the heat itself loads the body enough and it is better to get used to the high temperature first. Experts recommend drinking plenty of fluids and getting some rest, and athletes – getting ready for training in the heat in advance.   

Perhaps the main risk of sun exposure is melanoma, which is more likely to occur after every sunburn. Moreover, it is the temporary and intense radiation – for example, during a winter vacation in a hot country – that is much more dangerous in terms of melanoma than living in a sunny climate. The prevalence of the disease in Russia is growing , and this is not least due to winter trips to hot countries. You should not give up on vacation, but sunscreen should be the main means of personal care on a trip.     

Ice cream with hot drinks

A sharp change in temperature has practically no effect on tooth enamel – the hardest tissue in the human body , but it can significantly affect other tissues. Dentin is located under the enamel – a material consisting of microscopic tubes, which connects the pulp of the tooth (the so-called nerve) with the external environment. If the dentin is not completely protected by enamel, but is slightly open (for example, due to caries, thinning of the enamel as a result of too active cleaning, exposing the neck of the tooth), the pulp will react to temperature changes with pain.  

The dentist should determine the cause of the hypersensitivity and choose the treatment. Contrasts like hot coffee and icy water should be avoided by those who wear braces: the cement used to fix them expands and contracts with sudden changes in temperature, and the bracket may simply come off. 

local_offerevent_note August 21, 2021

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