How cold affects the body

Cryotherapy expert Erich Hohenauer explains why women are more sensitive to cold, what healing power lies in the cold, and how we can benefit from cold exposure.

Text: Ruth Jahn, photo: Unsplash

What puts greater strain on the body: intense heat or icy cold?

Erich Hohenauer: Heat puts greater strain on a healthy cardiovascular system. In summer, the body has to work to stay cool by stimulating the skin’s blood circulation to transport heat from inside to outside the body. To do so, the heart has to work harder. In addition, the body loses a lot of water with the sweat it produces to cool down – this also puts a strain on the heart, because it needs more power to transport the thick blood. In this sense, we can look forward to winter.

But icy temperatures also put a strain on our health. Heart patients in particular should therefore also avoid physical exertion in very cold weather.

That’s true. Cold also puts a strain on our cardiovascular system. In both hot and cold conditions, our body does everything it can to keep its core temperature, i.e. the temperature of the centre of the body where the most important organs are located, at 37 degrees. When it’s cold, the body has to work to keep heat inside the body by increasing blood circulation in the skin and thus causing the blood pressure to rise. The heart must now pump the blood through the veins against greater resistance, which can cause stress to the heart muscle and the walls of the vessels. In addition, the body shivers to produce heat.

“In evolutionary terms, we’re better suited to warmth.”
Erich Hohenauer

At a cosy ambient temperature of 27 degrees, the human body doesn’t need to cool or heat itself when naked. Doesn’t this indicate that we’re better suited to warmer temperatures?

This is certainly the case in evolutionary terms, because humans originated in the southern hemisphere. However, we’re relatively good at adapting to both hot and cold temperatures.

Can wading through a kneipp bath or taking cold showers help?

Yes, you can get used to the cold. The body adjusts its metabolism and blood circulation of the skin and forms more subcutaneous fat tissue. In particular, the body produces more brown fat inside the body. This stimulates the body’s own heat production. And ultimately, the core body temperature is also adjusted slightly. However, for these adjustments to take place, the body must be subjected to cold temperatures regularly. As with strength training, it’s all about consistency. Jumping into an icy lake once a year has few benefits and should only be done with caution.

“Exposure to the cold is said to have a positive influence on the body’s defence system, but there is no scientific evidence of this.”
Erich Hohenauer

Cold exposure is said to offer protection against flu and other infectious diseases. Is there any truth in this?

Exposure to the cold is said to have a positive influence on the body’s defence system, but there is no scientific evidence of this. Our immune system is extremely complex. It is possible that we can train our cardiovascular system by alternating exposure to hot and cold temperatures, for example when you take a sauna, because this causes the blood vessels to dilate and constrict again. This may improve blood circulation in the skin and thus benefit the immune system.

Are women more sensitive to cold than men by nature?

Yes, women tend to feel the cold more than men. There are three biological reasons for this: First, men’s muscles protect them to a certain degree from the cold, because muscle cells burn calories and thus generate heat. Second, women have thinner skin, so they tend to cool down more quickly. And third, the female body also loses more heat due to its relatively large body surface in relation to its body volume.

Does subjective sensitivity also play a role?

Yes, it’s similar to pain: temperatures that may feel cold to one person can be quite pleasant for others. The comfort zone for temperature sensation is very individual.

Cold can also have healing powers. It can take the edge off reactions to inflammation such as pain, redness and swelling. For example, if you hold burnt fingers immediately under cold water or put a cold pack on a strain. But can cold do more?

Cold has long been used as a therapy. For example, you can get rid of warts by freezing them with liquid nitrogen. In this case, cold is used to kill off superficial skin cells. With organ transplants, cold helps the transplant organ last longer. And after a heart attack or stroke, doctors sometimes lower the temperature of the tissue slightly as a protective medical measure. This protects organs by reducing their oxygen and energy consumption. In addition, any damaging processes at cell level are slowed down. The idea behind this is to virtually freeze the damage of a heart attack so that it doesn’t spread further.

“Severe cold temporarily relieves symptoms in some patients suffering from rheumatism.”
Erich Hohenauer

The cryotherapy business is currently booming, with patients suffering from chronic pain, rheumatism and insomnia seeking to ease their symptoms. Whole-body chambers and cryotherapy pods are currently experiencing a revival. The aim of this cold treatment at temperatures of around -100 degrees or down to almost -200 degrees is to lower the tissue temperature in order to slow down inflammatory processes or the transmission of pain stimuli. However, the effect has not yet been clearly scientifically proven. Nevertheless, the severe cold temporarily relieves the symptoms in some rheumatism patients. Some patients suffering from chronic pain also report an improvement.

Sports people also hope to reap the benefits of cold treatments.

Today we know that intensive and sudden physical training can lead to small injuries in the musculature. These little injuries trigger inflammatory processes which, under certain circumstances, can impair the performance of an athlete for several days. We’ve all experienced sore muscles. Taking short baths in cold water (around 10 degrees) helps dampen these inflammatory processes and can minimise the drop in performance. Sports people hope for a quicker recovery.

Is this only relevant for elite sports?

Cold therapy can give a small but decisive competitive edge in any multi-day competition. However, you should never take cold baths or apply cold packs after exercise without medical advice. You must always consult a trained professional or doctor first and tailor the treatment to your individual requirements. If used incorrectly, cold treatment can also have a negative impact on performance.

Dr. Erich Hohenauer, 35, is a rehabilitation scientist and works in the research laboratory of the University of Applied Sciences Southern Switzerland (SUPSI). He is also a lecturer at the International University of Physiotherapy in Landquart (THIM). In his research, he is particularly interested in how cold affects the human organism.