Are Cold Showers and Baths Really Bad for You?
Should you quit taking cold showers, using cold water immersion, or icing those sore muscles after a workout?
Cryotherapy, cold thermogenesis, icing, and other forms of cold exposure are all forms of recovery that I personally use nearly every day. In the article, “How to Use Cold Weather to Lose Weight,” and also in my article, “Cold Temps for a Hot Body” I outline many of the practical ways I do this—from keeping my office temperature cool to morning and evening cold showers to body cooling gear to compression gear with ice to cold baths.
Of course, the application of cold to an injured area or to a beat-up muscle is hardly a new concept. The Greek physician Hippocrates wrote about the use of cold therapy to control pain and swelling in the 4th century B.C., and the Roman physician Galen described the use of cold compresses for analgesia following soft tissue injuries in the 1st century A.D.
During the Middle Ages, ice was used for pre-surgical anesthesia, and ice therapy has been extensively used in the athletic training and physical therapy for the treatment of sports injuries for many years. But despite the seeming widespread acceptance of tossing a bag of ice on an injured ankle or aching shoulder, several years ago there was a surge of doubt concerning icing’s efficacy across the Internet.
The arguments a few years ago went something like this: when an injury occurs, your body creates inflammation as a healing response. So, if inflammation is the body’s natural way to heal an injury, why would you want to block this inflammatory process with ice?
Furthermore, there were claims that icing may increase the permeability of lymphatic vessels (tubes which normally help carry excess tissue fluids back into the cardiovascular system). Once this lymphatic permeability increases, there may be risk of a large amounts of fluid back flowing into the injured area, causing more swelling than may have occurred if you didn’t ice in the first place.
I addressed both of these concerns, and why icing really does work, in my article, “Tips For Burning More Fat With Cold Thermogenesis (And Why Icing Really Does Work).”
But now new evidence has emerged in the form of two brand new studies—studies that suggest cold water immersion and icing may actually impair strength gains, make your muscles smaller, or slow down recovery. In today’s article, you’ll learn all about these new studies, and whether you should quit taking cold showers, using cold water immersion, or icing those sore muscles after a workout.
The New Studies Against Icing
The first new study that suggests cold may not be all it’s chalked up to be is entitled, “Post-exercise cold water immersion attenuates acute anabolic signaling and long-term adaptations in muscle to strength training.”
In the study, researchers investigated the effects of the combination of strength training and cold water immersion through two separate studies. In one study, 21 physically active men strength trained for 12 weeks, 2 days a week, with either 10 min of cold water treatment or active recovery without cold water after each training session. Strength and muscle mass increased more in the group that didn’t get exposed to the cold water. Work capacity, muscle fiber size, and the number of cells per muscle fiber also increased in the active recovery group, but not the cold water group. In another study, nine active men performed a bout of single-leg strength exercises on separate days, followed again by either cold water or active recovery. The number of satellite cells and also the amount of phosphorylation (both of which cause muscle growth) increased more after the exercise with active recovery compared to the cold water immersion.
So, what does all this geek speak mean? It indicates that cold water immersion may attenuate the acute changes in satellite cell numbers and activity of kinases that regulate muscle growth (hypertrophy), which may translate to smaller long-term training gains in muscle strength and hypertrophy if you use cold water immersion after a workout. The researchers concluded that “use of CWI as a regular post-exercise recovery strategy should be reconsidered.”
The next study, entitled “Does Regular Post-exercise Cold Application Attenuate Trained Muscle Adaptation?” examined the effects of regular post-exercise cold application (icing) on muscular and vascular adaptations induced by moderate-intensity resistance training. In this study, subjects did a workout consisting of 5 sets of 8 wrist-flexion exercises at workload of 70-80% of the single repetition maximum, three times a week for six weeks. Half of the subjects immersed their experimental forearms in cold water for 20 min after the wrist workout and the other half served as control subjects without any cold water. Measurements were taken before and after the training period for wrist-flexor thickness, brachial-artery diameter, maximal muscle strength, and local muscle endurance.
Wrist-flexor thicknesses of the experimental arms increased after training in both groups, but the extent of each increase was significantly less in the cooled group compared with the noncooled group. Maximal muscle strength and brachial-artery diameter did not increase in the cooled group, while they both increased in the noncooled group. Local muscle endurance increased in both groups, but the increase in the cooled group was lower compared to the noncooled group. The researchers in this study concluded that “Regular post-exercise cold application to muscles might attenuate muscular and vascular adaptations to resistance training.”
So, at first glance, it would appear you should probably throw your ice buckets in the trash bucket!
Should You Stop Doing Cold Therapy?
However, there are two problems here.
The first problem is that the subjects weren’t working very hard.
Let’s face it: wrist flexor exhaustion by working out your wrists three times a week? Twice a week strength training sessions with three full days of recovery between sessions? A bout of single leg strength training exercises?
None of these activities in a lab surrounded by scientists in white lab coats quite reflect what, say, a professional Tour de France cyclist might experience during a brutal multi-day stage race with over five hours each day spend cranking out more wattage than the average person rides in an entire year of bicycling, or what an Ironman triathlete might experience during 10 hours of redlining their body in the heat, what a football player might experience during intense two-a-day practice sessions during a hot and humid football season, or what a bodybuilder might experience when visiting the gym one to three times a day to completely exhaust multiple body parts.
In other words, in the same way that many antioxidant studies will say that “antioxidants blunt the training response”, but really don’t put participants through very hard training at all, icing studies that use a relatively minimal amount of exercise to argue that icing and cold water immersion doesn’t work simply do not, in my opinion, translate into real world environments for hard-charging athletes and exercise enthusiasts.
But, let’s assume for a moment that icing or cold water immersion really does blunt the training response, and inhibit strength, muscle building, or recovery. These new studies still ignore the host of other benefits you can get from ice and cold that go way beyond bigger biceps. Here are just a few examples (with a full list of scientific references and studies at the end of this article):
-Formation of brown fat
Brown fat, or brown adipose tissue (BAT) is a special kind of fat found in most mammals. When you get cold, brown fat “turns on” and burns off your regular fat on your hips, stomach, legs, etc., in order to generate heat. Basically, brown fat burns glucose and free fatty acids to generate heat during cold stress.
One reason for this is because the hormone irisin is released from muscle tissue exposed to cold temperature. Irisin is involved in the “browning” of white fat (storage adipose tissue) into brown fat. Irisin also lowers myostatin, which (ironically, in light of these new studies suggesting cold inhibits muscle growth) actually allows for greater muscle growth. Irisin has also been shown to function in neuroprotection of brain tissue, and to kill certain types of cancer cells, including breast cancer tissue. Irisin has even been shown to lengthen DNA telomeres, the chromosomes on the ends of DNA strands which shorten as we age, thus potentially promoting longevity.
-Increase in mitochondrial density
Mitochondria are components in nearly all living cells, and often called the “power plants” of cells. Cold thermogenesis directly increase mitochondrial activity and efficiency in several ways. As you’ve already learned, the mitochondria in brown fat (brown adipose tissue) is upregulated in response to cold stress, which burns up extra
This same response also occurs in your muscles, via a process called “skeletal muscle uncoupling,” in which your muscles burn glucose and fats to generate heat in response to cold stress. The hormone adiponectin, which you’ll learn more about in a moment, also increases mitochondrial biogenesis, which increases both the number and efficiency of mitochondria within your cells, and improves your capacity to burn fuel during cold stress, exercise, and daily life.
-Increase in metabolic rate
Your body must burn calories and fat to keep your temperature at 98.6 degrees Fahrenheit. In addition to various hormonal changes that increase metabolism, fat burning, and muscle building, you simply burn a significant number of extra calories when you include practices like keeping the room temperature cold, or a weekly 20-45 minute cold bath or a daily morning and evening cold shower.
-Increase in adiponectin
The hormone adiponectin is released from fat tissue in response to cold. The list of benefits from adiponectin read something like a “miracle drug,” as it increases metabolism and fat burning, increases insulin sensitivity, induces mitochondrial biogenesis in muscle tissue, decreases systemic inflammation, relaxes epithelial tissue, relaxes cardiac tissue, kills certain types of cancer cells, and is positively correlated with longevity. Whew!
Research has shown that adiponectin triggers the release of free fatty acids from fat tissue and the uptake into muscle tissue to be burned as fuel. It increases metabolism without increasing hunger. As mentioned earlier, it increases the number of mitochondrial in skeletal muscle, and makes mitochondria more efficient in their generation of energy. This results in the production of fewer free radicals and reduces the chance of free radicals altering or mutating DNA.
Adiponectin increases the uptake of glucose into muscles, and allows nutrients to be funneled away from fat formation, and into muscle. It reduces inflammation and relaxes cardiac and epithelia tissue, and kills harmful junk cells and certain types of cancer cells via a natural process called apotosis.
-Apoptosis
Speaking of apoptosis, or programmed cell death that results in longevity, it been shown that direct exposure of fat to cold temperatures can cause the subcutaneous fat underneath the cold area to undergo cold-induced apoptosis, become inflamed, and be reabsorbed, resulting in a form of spot reduction of stomach fat.
-Increase in growth hormone
Cold exposure can increase levels of “heat shock proteins,” which increase growth hormone levels. Growth hormone is also inversely related to blood glucose levels, so by keeping glucose levels down via cold exposure before bedtime, you may maximize your natural growth hormone release.
-Increased immune system health
Glutathione, T-killer cells, lymphocytes, and a variety of other immune system cells and functions are strengthened and enhanced in response to cold (so no, cold exposure doesn’t make you more sick or susceptible to cold!).
-Increased insulin sensitivity
Cold thermogenesis can significantly enhance insulin sensitivity. Insulin helps nutrients to be transported into various body tissues such as fat and muscle. But insulin resistance is a condition in which your body’s cells do not efficiently respond to insulin, making you “resistant” to it’s function of transporting nutrients (especially glucose) into your cells. This results in chronically high blood glucose levels, obesity, and systemic inflammation. Insulin resistance is also a major contributing factor to development of Type-II diabetes, heart disease, and chronic metabolic diseases that affect nearly 2/3 of all Americans, including Alzheimer’s and cancer.
By increasing insulin sensitivity, cold exposure can cause nutrients to be pulled into muscles more effectively, fat to be burned by brown adipose tissue more effectively, a reduction in systemic inflammation, a reduction in insulin related diseases, and a potential for better nutrient partitioning and better storage of glycogen (storage carbohydrate). Cold stress amplifies insulin sensitivity, directing nutrients away from fat tissue, and instead shuttling them into muscle.
-Improved thyroid health
Your thyroid gland rests on the neck, near the Adam’s apple. It influences many other glands and organs, regulates body temperature, and controls overall metabolism.
Cold exposure has been shown to boost thyroid levels in animal models, and NIH funded experiments are currently underway to confirm cold’s effect on human thyroid levels as well.
-Better sleep
Last week, you learned about a free sleep hack that involved putting your barefeet outside of the covers to cool your body and allow for more deep sleep and getting to sleep faster. In the same way, cold showers, cold baths and other forms of cold thermogenesis can enhance sleep, and make it easier to fall asleep and achieve a deeper sleep, especially if you use evening or nighttime cold exposure. Furthermore, in the same way that looking at sunshine in the morning can help send a message to your body to increase cortisol and to wake up, an invigorating morning cold shower may help “reset” circadian rhythms and allow you to more easily fall asleep later that night.
Summary
Ultimately, there is indeed evidence to suggest that when you’re doing a mild to moderate amount of resistance training, the frequent use of icing and cold water immersion may indeed blunt the training response, and possibly inhibit muscle and strength building.
But obviously, with the host of benefits that cold can provide, we need to consider far more than simply whether or not cold exposure can make infrequent exercisers strong or not. Do I personally plan on avoiding my morning “fat burning” cold shower, or quitting my habit of using cold baths or a jump into the icy cold river to cool inflammation and body temperature after an extremely difficult multi-hour workout? Not anytime soon, and especially not until I see a study that shows cold to actually inhibit the host of other benefits you’ve learned about in this episode!
If you have questions about whether cold showers and cold baths are really bad for you, then leave your thoughts over at the Facebook.com/GetFitGuy page!
Studies and evidence referenced in this article:
- A colder environment increases BAT activity and metabolism
- Cold-adaptation, increased resting metabolism, and weight loss
- Even lean subjects increase BAT and burn fat
- Shivering releases irisin, which turns white fat
into brown fat - Irisin correlates to longer telomeres and longevity
- Irisin may explain how cold thermogenesis can
build muscle - Irisin increases insulin sensitivity and nutrient uptake into muscle
- Can irisin help fight certain types of cancer?
- BAT burns glucose and boosts metabolism in humans
- Cold stress turns white fat into “beige” fat
- BAT therapy to combat obesity
- BAT burns fat in the blood stream
- BAT, glucose, insulin, and cold stimulus
- BAT contributes to only some of the metabolic increase of cold stress
- BAT activity in humans inversely correlate to obesity
- BAT increases and decreases with timed cold exposure (backup)
- Cold weather increases BAT, but can take time to formopens PDF file
- Rising environmental temperatures linked to obesity?
- Brown Fat (BAT) detected in subjects after cold exposure
- Age, gender, insulin sensitivity, and other factors in BAT activity
- Exercise in humans and mice can create new BAT(backup)
- BAT in various age groups
- Brown Fat sucks up glucose from the blood stream
- Cold exposure converts white fat to “beige fat” in mice
- BAT-disabled mice become obese
- Cold exposure creates new “rBAT” in mice
- Cold therapy, but not ephedrine, activate BAT
- BAT, thermogenesis, and bone density
- BAT and food digestion
- Intermittent fasting likely produces new BAT
- Fasting and BAT activation
- Women and BAT levels
- Capsinoids increases BAT activity
- Sleep, light-cycles, melatonin and BAT in humans
- Cold exposure, blood glucose, and BAT in rats
- Summary on current BAT research
- Summary on current BAT research
- Cold exposure increases adiponectin levels
- Adiponectin burns fat
- Adiponectin increases mitochondria and reduces free radicals in human skeletal muscle
- Adiponectin increases mitochondria in human skeletal muscle
- Adiponectin increases glucose uptake and fat burning in skeletal muscle
- Adiponectin pushes glucose into muscle
- Adiponectin, obesity, insulin resistance,
and fat-burning - Adiponectin resistance in obesity
- Adiponectin may help fight cancer
- Low adiponectin and heart disease, diabetes, systemic inflammation, and metabolic disorder
- Adiponectin, HDL, and diabetes
- Adiponectin as a treatment for obesity and heart
disease - Adiponectin, fasting, and circadian rhythms
- Adiponectin burns off glucose and increases insulin sensitivity
- Adiponectin is produced from muscle as well as fat, in mice
- Exercise increases adiponectin levels in obese men
- Glucose uptake may help explain CT’s
ability to preserve and build muscle - Cold exposure increases powerful anti-oxidant glutathione
- Cold exposure boosts the immune system
- Cold exposure boosts the immune system
- Carb and fat burning ratios vary during shivering
- Cold exposure and longevity in mice
- Skeletal muscle uncoupling after thermal loading
- Muscle protein “Sarcolipin” involved in cold thermogenesis
- The sympathetic nervous system and fat-burning during cold exposure
- Transplanted BAT increases glucose and insulin function
- “Constitutionally lean” women have active BAT even at room temp
- Glucose utilization, BAT, and intermittent fasting in rats
- Humans have both “original” BAT and “recruitable” BAT
- BAT can boost metabolism by 30% at minimal room temp reductionsopens PDF file
- Cold stress may increase thyroid activity
- Cold thermogenesis may mimic melatonin,
explaining better sleep when using the Cool Fat Burner - Cold exposure can increase “heat shock proteins,” which can increase growth hormone levelsopens PDF file
Image Courtesy of Shutterstock.
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About the Author
Ben Greenfield received bachelor’s and master’s degrees from University of Idaho in sports science and exercise physiology; personal training and strength and conditioning certifications from the National Strength and Conditioning Association (NSCA); a sports nutrition certification from the International Society of Sports Nutrition (ISSN), an advanced bicycle fitting certification from Serotta. He has over 11 years’ experience in coaching professional, collegiate, and recreational athletes from all sports, and as helped hundreds of clients achieve weight loss and fitness success.
