Hot Natured vs. Cold Natured- It's All in the Genes!

Have you ever wondered why some people are perpetually cold, even in the heat of the summer while others aren’t phased by cold temperatures? Regardless of what climate you grew up in or live in, genetics play a large role in how your core temperature affects your daily response to hot or cold environments.

A common mutation or genetic variant found in the skeletal muscle gene called ACTN3 (alpha-actinin-3) makes it easier for people to tolerate cold temperatures. The ACTN3 gene produces a protein of the same name. Research shows that if you have this gene mutation or alpha-actinin-3 deficiency, you can maintain a higher core temperature, conserve more energy and shiver less when exposed to cooler temperatures than those who have more ACTN3 genes.

Shivering is the body’s response to cold and acts to generate heat and raise body temperatures. Skeletal muscles are made up of fast and slow muscle fibers, and alpha-actinin-3 is most often found in fast muscle fibers that have a direct effect on muscle functions and the production of heat. The greater the muscle function, the higher the ability to conserve energy, leading to higher core temperatures and less shivering when exposed to cold temperatures.

One in five people lack the ACTN3 gene which can be traced back to generations of people who migrated out of Africa and who settled in the colder climates of Asia and Europe. It’s important to note that an alpha-actinin-3 deficiency does not cause muscle disease, but we continue to uncover the correlation between genetics and muscle function that will allow the development of treatments for those who do suffer from muscle disease and dystrophy, as well other more common genetic conditions including Type 2 diabetes and obesity.