People who are afraid of cold vs. people who are resistant to cold, who is healthier? The truth is...

As the temperature gradually drops, some people are still shivering in thick down jackets, while others are relaxed in the cold wind in single clothes. This makes people curious: Why are some people so cold-resistant? Does fear of cold and resistance to cold indicate the health of the body?

Today we will talk about the differences between these two groups of people and the health truths hidden behind them.

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Why are some people more resistant to cold?

Antifreeze is human's adaptation to cold climate. After tens of millions of years of evolution, people who have adapted to the cold have developed their own distinctive characteristics.

From a genetic perspective, the ACTN3 gene of people who are resistant to freezing may have the R577X mutation and lack α-actinin-3. This change allows muscles to generate heat through low-intensity, continuous contraction without consuming a lot of energy. In other words, people who are resistant to freezing can maintain their core temperature and resist the cold in a cold environment without taking in extra energy. About 1.5 billion people in the world have this mutation.

People who are resistant to freezing also show unique physiological characteristics. A study comparing the Inuit with tropical residents found the secret of their adaptation to cold:

First, the body's metabolic rate is significantly higher than that of ordinary people. The basal metabolic rate is 3% to 19% higher than that of temperate or tropical residents, and body temperature is maintained through higher heat production;

In addition, the Inuit have a greater ability to produce non-shivering thermogenesis, a form of heat production driven by brown adipose tissue that can be sustained for longer periods of time without causing fatigue as quickly as shivering.

Moreover, their skin temperature drops in cold environments, forming a "natural insulation layer" that reduces heat loss. In contrast, tropical residents have higher body surface temperatures in cold environments, and this lack of adaptation makes them more susceptible to discomfort from the cold.

In addition to this natural insulating layer, they also have more subcutaneous fat, which is not only a natural "insulating material", but also stores the energy needed in cold environments.

After years of evolution, they have also reduced their ability to dissipate heat. First, they have fewer sweat glands, and second, their body proportions are lower, with a small ratio of surface area to volume, both of which can reduce heat loss.

They also have a unique self-protection ability - cold-induced vasodilation (CIVD), that is, in a cold environment, the peripheral tissue temperature drops due to the long-term vasoconstriction of the skin and tissues. When the temperature of the fingers and toes is low enough and the core body temperature remains high, the opening of the arteriovenous anastomosis will trigger this abnormal vasodilation. This ability can protect peripheral tissues from frostbite.

Perhaps the cold-resistant people around you have one or more of the above characteristics, but it is also possible that they have gained better resistance to cold through long-term and repeated exposure to mild cold.

People who are afraid of cold vs. people who are resistant to cold

Who is healthier?

Fear of cold and resistance to freezing cannot be directly regarded as signs of health, but are different manifestations of physical conditions. These changes in humans have a double-sided impact on health.

For example, although people who lack α-actinin-3 protein have better cold resistance, endurance, and wilderness survival ability, their overall strength and explosive power have decreased. During exercise, due to the weaker mechanical properties of muscles, they are more likely to suffer micro-injuries, and their inflammation levels and soreness are more significant. They need a longer recovery period, otherwise they are prone to chronic injuries. Some studies have even found that such people may have a higher risk of diabetes.

People who do not lack α-actinin-3 protein have greater explosive power during exercise, are more likely to suffer severe muscle damage, show stronger catabolic reactions, and their muscles are more easily fatigued.

Therefore, we cannot regard whether we are afraid of cold as an indicator of health. Instead, we should pursue the comfort of life itself and respond to the cold reasonably according to our own conditions, so as not to let fear of cold or resistance to freezing become an obstacle that affects the quality of life.

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A guide to keeping warm in winter

Whether you are afraid of cold or resistant to freezing, only by finding a balance that suits you can you face the cold challenges of winter more calmly.

For people who are afraid of cold, the key is to improve the body's heat production and warmth-keeping effect. You can promote metabolism by increasing exercise appropriately, such as brisk walking or light strength training every day, which can not only enhance physical fitness but also improve peripheral circulation; at the same time, eat more foods rich in protein and iron, such as lean meat, eggs and dark green vegetables, to help "warm up" the body; in addition, pay attention to daily warmth, especially keeping the hands, feet, waist and abdomen warm, which can effectively reduce heat loss.

For people who are resistant to freezing, although they have a strong ability to withstand cold, they still need to keep warm to avoid the potential threat of cold to health. Especially for people who work or move in low-temperature environments for a long time, they should add clothes in time to protect cardiovascular and cerebrovascular functions and avoid diseases caused by excessive exposure; at the same time, do not ignore the impact of cold on the skin and respiratory tract. You can use a humidifier to keep the air moist and apply moisturizing products to exposed skin in time to reduce the possibility of dryness and frostbite.

Conclusion

In winter, whether you are afraid of cold or resistant to cold, you should pay attention to your body's signals and adjust your lifestyle flexibly.

A proper work and rest schedule, a balanced diet, and exercise habits are the core strategies to resist the cold. The proper use of modern tools, such as hand warmers, electric blankets, or thermal pads, can also effectively improve comfort. Most importantly, don't let the cold become a psychological burden. Only by dealing with the cold winter scientifically can you live a healthy and safe life.

References

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[3]LeeFX,HouwelingPJ,NorthKN,etal.Howdoesα-actinin-3deficiencyaltermusclefunction?MechanisticinsightsintoACTN3,the'geneforspeed'.BiochimBiophysActa.2016;1863(4):686-93.

[4]RodasG,Moreno-PérezV,DelCosoJ,etal.Alpha-Actinin-3DeficiencyMightAffectRecoveryfromNon-ContactMuscleInjuries:PreliminaryFindingsinaTop-LevelSoccerTeam.Genes(Basel).2021;12(5):769.

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Planning and production

Author: Jiang Yongyuan, Master of Internal Medicine, Third Military Medical University

Reviewer: Cha Ying, deputy chief physician of endocrinology at the Shanghai Fifth People's Hospital affiliated to Fudan University