Women get cold more easily than men, older people more than younger ones. But targeted cold training can help everyone to get by with less heating. Researchers reveal why a cold shower works wonders, but a fat pad doesn’t.
Gender, age, stature, metabolism: when someone starts to feel cold depends on many factors. While some of these are unchangeable, others can be influenced and the body can be made more tolerant of cold. The solution is: training.
In fact, our cold sensitivity sends itself to training camp every year anyway – due to the change of seasons. “If we have 13 or 14 degrees in April, we find it warm and go out without a jacket. If the temperatures drop to 13 or 14 degrees in autumn, we freeze,” explains Ralf Brandes, Professor of Physiology at the Goethe University in Frankfurt . Our body adjusts itself within a relatively short period of time. This adaptability can now also be used to feel comfortable in a less heated apartment.
A longer-term increase in cold tolerance is possible through regular and ideally daily exposure, says Thomas Korff, professor at the Institute for Physiology and Pathophysiology at Heidelberg University. “We see that, for example, in people who work outdoors. They usually move more, which is probably why they have more muscles and a higher basal metabolic rate.” They also unconsciously adjusted their behavior: “Someone who works outside a lot probably also changes their diet because an increased basal metabolic rate requires more calories.” Overall, this improves the body’s ability to perceive cool temperatures as pleasant.
On the other hand, Korff advises against feeding on a protective layer of fat: white body fat is something other than the actually protective subcutaneous fat. “Of course, white body fat also has an insulating effect, but only where it is.”
However, there is also brown fat, which was long thought to be found only in infants. Instead, adults also have this type of fatty tissue, which acts like the body’s own heating system – albeit usually only in small quantities. Babies, who still don’t have enough muscles to generate enough heat and are much more sensitive to cold, need brown fat to maintain their core temperature. Studies show that cold stimuli can increase the proportion of brown, warming fat in adults.
However, the research on this is not yet mature, explains Korff. It is clear that even small changes in behavior can make a difference in being less sensitive to cold: “It can help not to drive all the way to the office in the car, but to walk the last kilometer or take the bike right away.” If you want to challenge yourself more, you can gradually get used to contrast showers over a longer period of time, says the physiologist. According to a Dutch study, these not only make you stronger, but also seem to have a positive effect on the immune system.
But all adaptation has limits – also because a lot of the perception of cold depends on factors that cannot be changed. 37 degrees: This is roughly the core temperature that our body wants to maintain at all costs. Receptors on our skin constantly measure whether the temperature of our environment deviates from this. When it’s cold, we unconsciously make ourselves smaller in order to reduce our surface area and thus emit less heat.
If the cold persists, our vegetative nervous system – more precisely: the sympathetic nervous system – kicks in. It begins to narrow the blood vessels in the periphery, such as in the hands or feet. A process called centralization. In the course of this, the blood is directed from the outside to the inside. If we start to tremble, the body is trying to produce heat. These reactions to cold are the same for most people – but the point at which they start is not.
“There are very big individual differences in sensitivity to cold,” says Ralf Brandes from the Goethe University in Frankfurt. There are also differences between body regions: “Anyone who goes into cold water will notice that the legs are less sensitive to cold than the stomach,” says Brandes, who is also Secretary General of the German Physiological Society. Women often tend to freeze. “Men, on the other hand, usually have a higher proportion of muscle mass, thicker skin and a better surface-to-volume ratio,” explains Thomas Korff from the University of Heidelberg.
Age also plays a role. “As a rule, young adults deal best with low temperatures because they have a higher basal metabolic rate.” The basal metabolic rate describes how much energy a person basically produces throughout the day – a process that tends to be reduced in older people because they have less muscle mass on average, explains the physiologist. “A higher proportion of muscle ensures that more heat is produced in the body.”
Another factor could be certain genes. A research team led by the Swedish Karolinska Institutet found that one in five people worldwide lacks the protein alpha-actinin-3 in their muscle fibers. Such a deficiency improves cold tolerance. The scientists suspect that the gene mutation likely provided an evolutionary advantage when humans migrated from Africa to Europe more than 50,000 years ago.
Despite all the adaptability, the perception of temperature remains highly individual, emphasizes Korff – and in this context refers to the new energy-saving regulation, under which many offices can only be heated to 19 degrees since October 1st: “There are people who at At such temperatures, the centralization makes fingers stiff and typing harder, while others lose attention. All of this comes at the expense of performance.” General regulations like these do not take individual sensitivity to heat and cold into account, criticizes Korff. “So from a physiological point of view, they’re nonsense.”
(This article was first published on Tuesday, October 11, 2022.)
