WARNING!
This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.
By Dr. Mercola
Sometimes the simplest strategies can have a tremendous impact on your health and wellness. For example, exposure to extreme temperatures may serve as a catalyst to improve your health and also the health of your unborn children. In previous interviews with Rhonda Patrick, Ph.D., we discuss the importance of mitochondrial function and how exposure to extreme temperatures can improve your mitochondrial health.
Estimates suggest you may have from 15 to 50 quadrillion mitochondria throughout your body. When they are not working properly, your body's ability to generate energy is severely impaired. Another factor important in the burning of energy is the percentage of brown fat you carry. Brown fat generates heat by burning calories and appears to play other physiological roles beyond heat generation.
Your body fat percentage is a useful gauge that dictates your metabolic health or dysfunction. Generally speaking, lower levels of body fat (to a point) are associated with better health outcomes. However, this refers to white fat, the kind that accumulates in your abdomen, upper thighs and upper arms.
However, researchers know the more brown fat you carry, the higher your metabolic rate and the lower your risk of metabolic dysfunction and of becoming overweight. New research1 demonstrates males may experience epigenetic changes when exposed to cold temperatures prior to mating that are passed to their offspring, appearing as a greater percentage of brown fat distribution.
Brown Fat Burns More Energy
Most fat cells in the human body store energy, but everyone has a small amount of brown fat cells, the purpose of which is to burn energy and generate heat. In a recent paper in Cell Reports,2 researchers believe they have uncovered the estrogen related receptor gamma (ERRy) gene highly active in brown fat cells. The team found brown fat cells express the ERRy gene in all temperatures and not just in the cold, while white fat cells do not express it at all.
The ability of brown fat to help your body acclimatize to colder temperatures was a skill scientists discovered in a groundbreaking study in 1961.3 For one month, U.S. Army researchers exposed 10 nude men to temperatures in the low 50s. By the 14th day most of the men had stopped shivering and their bodies appeared to be making heat in another way.4 Today, researchers understand brown fat cells deserve the credit for your ability to acclimatize to cold conditions.
Although your first response to cold is to shiver, your body eventually makes enough brown fat to take over heat production and burn extra calories. When you're first exposed to cold, the body attempts to prevent heat loss by shrinking blood vessels, increasing blood pressure and heart rate. It's important to remember this and to acclimatize yourself slowly, as cold induced blood pressure swings may trigger a heart attack or stroke in at-risk individuals.5
In the Study of Mice and Men
Recent research using an animal model demonstrates males who spend time in lower temperatures prior to mating produce offspring with more active brown fat tissue.6 This quite literally means the environment has an impact on the father's ability to pass epigenetic changes to his offspring.
Initially, researchers found people born between July and November had significantly more active brown adipose tissue than individuals born between January and June. The former were conceived in the colder half of the year and the latter were conceived in the warmer part of the year.
In order to delve further into this correlation, researchers conducted studies on mice.7 Splitting the mice into two groups, one group was kept near 74 degrees Fahrenheit (F) while the other was kept at a cool 47 degrees F. The animals were then allowed to mate. An analysis of their offspring showed the environmental temperature of the male made a difference in the level of brown fat tissue in the babies, but the temperature of the females were kept in did not.
The offspring of the males kept in cooler conditions were better protected against excess weight gain and against metabolic disorders.8 This research confirms prior studies demonstrating environmental factors have the ability to modify epigenetic pattern of sperm.
However, this is the first time ambient temperature has demonstrated an ability to make genetic changes that are passed on to the offspring. The results of this study also confirm observations of people living in colder regions who have particularly high levels of brown fat tissue as compared to those who live in warmer, tropical climates.9
Cryotherapy Activates Brown Fat
Most people crave homeostasis, the effortless state in which the environment meets your physical needs and your body can rest. Western living has enabled most to achieve this throughout the day. Indoor plumbing, central heating, artificial lighting and supermarkets allow us to fine-tune the environment so you may wake up long past sunrise, go to work in a heated car and spend the day in an air-conditioned office.
Many get home without ever being outside for more than a few minutes. However, this effortless homeostasis has damaged muscles and broadened waistlines. The rationale for exposing yourself to cold temperatures has to do with the benefits associated with hormesis. Cold temperatures may help you burn body fat, and mitochondrial biogenesis is directly involved in this process.10 During exposure to cold, your body increases production of norepinephrine in the brain, which is involved in focus and attention.
Colder temperatures help you think more clearly11 and researchers have found that people perform tasks better when the room temperature is set at a cooler setting then a warmer one.12 Further, individuals are less inclined to undertake cognitive problems in the summertime as the warmer weather uses glucose needed for mental processes.13 Cold has also been shown to improve mood and alleviate pain as it lowers inflammation.
Norepinephrine is more commonly known as a neurotransmitter but also acts as a hormone. One of the functions is to cause vasoconstriction helping your body conserve heat and acting as a signaling molecule to make more mitochondria in your fat tissue. Each of these functions help you to better prepare the next time you're exposed to cold weather as the more mitochondria in your fat cells, the better you can withstand lower temperatures.
This acclimatization to colder temperatures is the result of your body's ability to generate more heat. Researchers have demonstrated when men are exposed to cooler temperatures they increase the amount of brown fat in their bodies and enjoy a corresponding boost in metabolism.14
Other Cold Exposure Benefits
As your body works harder to maintain your core temperature, it burns more energy and calories to stay warm then it does in the summer months. If you have outdoor allergies, pollen counts are almost nonexistent in the cold weather. This means cooler temperatures may help improve your allergic response to outdoor allergens. However, mold and dust mite allergies may be worse during the winter months as you're spending more time indoors.
Sleeping during the winter months and colder weather is also more enjoyable.15 This happens since your body's core temperature naturally drops as you're falling asleep. Keeping your room temperature at 70 degrees can help your core temperature drop more quickly and thus fall asleep more easily.
A former material's scientist from NASA, Ray Cronise, devotes his time and energies to researching the benefits of cold exposure. His work prompted the invention of The Cold Shoulder Calorie Burning Vest by Wayne Hayes, professor at the University of California.16 The vest, packed with ice, is meant to be worn sporadically during the day to help acclimate you to cold temperatures, burn calories and activate brown fat.
Brown Fat Stabilizes Blood Glucose and Reduces Middle-Age Spread
An additional benefit to generating greater amounts of brown fat is the improved ability your body has to regulate blood glucose.17 In 2015, a professor of energetics and health at Maastricht University in the Netherlands enrolled eight overweight men in their late 50s with a diagnosis of Type 2 diabetes to determine how short-term cold exposure may alter their body.
Dressed in just shorts, the men sat in a 57-degree F room for six hours a day for 10 straight days. During this time their insulin production and blood levels were monitored. At the end of the study, their bodies metabolized glucose 43 percent more efficiently than when they started.18 In other words, just two weeks of cold exposure began to reverse their symptoms of diabetes.
In another study,19 researchers found people with higher levels of brown fat exhibited faster metabolic rates, better blood sugar control and greater insulin sensitivity. In this study, the men were exposed to mildly cold temperatures for up to eight hours in order to activate the brown fat they already carried.
Those who had higher levels of brown fat at the beginning of the study showed an increase in resting metabolism, insulin sensitivity and glucose processing. One of the study's authors noted,20 "We showed that exposure to mild cold raised whole body energy expenditure, increased glucose removal from circulation and improved insulin sensitivity in men who have significant amounts of brown adipose tissue depots."
Since activated brown adipose tissue increases metabolic rate and energy burn, it makes sense that with a reduction in brown fat tissue as you age, your thermogenic activity is reduced and you may experience a broadening waistline. This was demonstrated in an animal model study.21 Mice lacking a gene known as platelet activating factor receptor (PAFR) became far more obese with age than the normal control mice.
The PAFR gene is responsible for inflammation and fat transfer. Researchers believe deactivating it impairs the function of brown fat and caused the mice to become obese. This may be associated with a tendency to gain weight with age as brown fat is much less active as you age.
Interestingly, your body may also have something known as beige fat.22 Although brown and beige fat are similar, they have two distinct functions in your body and researchers are only at the beginning stages of discovering the differences and how they may interact.
Heat Stress Also Benefits Your Mitochondria, Brain and Heart
While cold stress has the effect of activating brown adipose tissue, heat stress is an important way of optimizing heat shock proteins (HSP) inside your cells, supporting biogenesis of more mitochondria and supporting your brain and heart health.23 Over time, HSP are damaged and need to be renewed. An accumulation of damaged HSP may lead to plaque formation in your brain or vascular system. Heat stress helps to prevent this chain of events.24
Heat also has some profound effects on your brain. Your body responds to heat through the production of dynorphin,25 the chemical opposite of endorphins. However, dynorphins sensitize your brain to endorphins, which may have a mood boosting effect. The reactive oxygen species generated when you're exposed to heat also benefits your brain by increasing the production of growth factors and brain derived neurotrophic factor.26
Three Ways to Increase Your Brown Fat Stores
Given the emerging benefits of brown adipose tissue to yourself and your children, you may be wondering how you can get more of it. Researchers are excited about the potential for medical intervention to develop more brown fat in the treatment of obesity, but I advise being wary of any solution that comes in pill form as that typically comes with a long list of side effects.
Instead, consider some of the following all-natural and noninvasive methods, all of which have demonstrated the ability to promote brown fat production and activation.
1. Exposure to cold: Scientists have repeatedly found that they can activate brown fat in adults by exposing them to cold temperatures. In one study,27 men burned more calories when cooled and lost white fat, the kind that causes obesity.28
Swedish research published in 2009 found cold temperatures increased activity in the subjects' brown fat regions,29 increasing cold-induced glucose uptake by a factor of 15. Based on animal models, researchers estimated just 50 grams of brown fat (which is less than what most study volunteers have been found to have) could burn about 20 percent of your daily caloric intake — and more if "encouraged." Here are a few simple cryotherapy options you can do at home:
- Place an ice pack on your upper back and upper chest for 30 minutes per day
- Drink about 500 milliliters (17 ounces) of ice water each morning
- Take ice-cold showers
- Immerse yourself in ice water up to your waist for 10 minutes, three times per week. (Simply fill your tub with cold water and ice cubes)
2. Exercise: In one mouse study,30 animals converted white fat into brown fat simply by exercising. The study found that during exercise, the animals' muscles released an enzyme called irisin that triggered the conversion of white fat cells to brown.
Preliminary studies presented at the 2013 annual meeting of the American Diabetes Association also showed both mice and men experienced beneficial "browning" of fat following exercise. Among men, the benefits were found after 12 weeks of training on an exercise bike. One of the researchers, a postdoctoral fellow at Joslin Diabetes Center, said:31
"Our results showed that exercise doesn't just have beneficial effects on muscle, it also affects fat … It's clear that when fat gets trained, it becomes browner and more metabolically active. We think there are factors being released into the bloodstream from the healthier fat that are working on other tissues."
3. Melatonin: Consuming melatonin stimulates the appearance of "beige" fat, which some researchers believe may explain why melatonin helps control body weight, along with its metabolic benefits. As reported in Science Daily:32
"The study … showed that chronic administration of melatonin sensitizes the thermogenic effect of exposure to cold, heightens the thermogenic effect of exercise and, therefore, constitutes excellent therapy against obesity. The fact is that one of the key differences between 'beige fat,' which appears when administering melatonin, and 'white fat,' is that 'beige fat' cell mitochondria express levels of UCP1 protein, responsible for burning calories and generating heat."
It's also well proven that lack of sleep is linked to obesity, and if you're not getting enough sleep, there's a good chance your melatonin production is not up to par either. It is probably unwise to take melatonin supplements for this effect. Instead, I'd recommend stimulating your own melatonin production as I've discussed in previous articles such as "16 Chronological Tips to Improve Your Sleep."