Physical activity is good for the mind, body, and soul. But there are a myriad of problems associated with engaging in excessive exercise (or what I call, “excess-ercise”).
First of all, it violates the cardinal rule of moderation in all things. Research shows that the excessive mechanical stresses and unnatural sheer forces of too much exercise can harm your joints, gastrointestinal (GI) system, genito-urinary system, and even your eyes.
This is particularly true with repetitive motions and flat, hard, artificial surfaces—like those found in indoor gyms. Meanwhile, enlightened exercise experts like Erwan Le Corre, the modern-day “Tarzan,” have explained for years how the body is designed for nonrepetitive exercise outdoors in Nature, instead.
Secondly, contrary to some belief, excessive “fitness” is no guarantee of longevity. In fact, it can lead to heart problems—affecting blood circulation, the nervous-conduction system of the heart, and even the heart muscle itself. That’s why we routinely hear about relatively young, healthy marathon runners and cross-country endurance skiers dropping dead of heart attacks.
And now, a new study points out a third potential problem with excess-ercise: It can disrupt your body’s normal thermal (temperature) regulation.1
As a result, it’s possible to encounter frostbite, hypothermia, or even death if you overexercise outside in cold weather.
To understand how this can happen, it’s necessary to know some basics about body temperature and exercise…
The link between excess-ercise and low body temperature
Body temperature is critical to all cellular and metabolic functions. And it’s regulated in many ways.
To help maintain a constant temperature, the body has several natural reflexes—including shivering, sweating, and dilation or constriction of the blood vessels—to adjust blood circulation, energy, and fluids. Your conscious choices and decisions also play an important role, like seeking shelter from the cold or shade from the heat.
When you exercise, excess heat produced by your muscles is partially dispersed through temperature-regulating reflexes like sweating. But research shows that the sensation of temperature via the skin may be reduced during exercise.
Some scientists speculate that this loss of normal temperature sensation may relate to the built-in mechanism that dulls pain during exercise by releasing naturally occurring opiates into the brain, known as the “runners high.”
Of course, the new study I just mentioned found that this lack of temperature-regulating reflex doesn’t only affect your sweating mechanism.
In fact, the researchers reported that the normal cold-adaptive mechanism of shivering also doesn’t kick in until your core body temperature has reached a lower level than it would if you weren’t exercising.
The physiology of cold-weather exercise
To reach these conclusions, the researchers gathered 11 healthy, young men and measured their core body temperature, skin sensation of heat or cold, and perception of cold. They also monitored the study participants’ blood pressure, heart rate, and oxygen uptake.
These measurements were performed while the men were resting in a stable environment with normal temperatures during low-intensity exercise—and again when they were partially submerged in a cold-water tank.
Results showed that the participants’ body temperatures dropped while they were exercising in the cold. But they couldn’t perceive this decrease as well as they could when they weren’t exercising.
Meanwhile, their skin temperature sensation appeared to be unaffected. Researchers explained that the exercise likely wasn’t intensive enough to elicit the “runners high” response that dulls pain and blocks skin sensations.
And it stands to reason that the core temperature would continue to drop—and participants would perceive it even less—with increasing exercise. Meaning they might not feel cold enough (or have the good sense) to stop exercising and go inside, or to put on more clothing to protect themselves from the cold.
And, as I mentioned earlier, that can lead to serious—or even fatal—health issues.
Don’t be left out in the cold
The bottom line is to beware of exercising too much or too long in cold environments this winter—as you may not be able to safely regulate your body temperature or realistically feel the intensity of the cold.
Of course, that doesn’t mean you shouldn’t take a ramble through the winter wonderland or build a snowman with your grandchildren. Just be moderate with your physical activity—and dress appropriately.
Studies consistently show optimal health benefits are associated with getting 140 minutes of weekly moderate exercise, preferably outdoors in Nature, especially as you get older.
It’s also important to pay close attention to your body temperature when you’re outdoors in cold weather—especially if you’re exercising. Just because you’re not shivering does NOT mean your core body temperature isn’t dropping to dangerous levels.
So, bundle up when the temperatures drop, and monitor how much time you spend outside—and please, don’t overdo it.
As veteran actor Michael Conrad said each week on Hill Street Blues, “Let’s be careful out there.”
1“Effects of low-intensity exercise on local skin and whole-body thermal sensation in hypothermic young males.” Physiology & Behavior, 2021; 240: 113531.