Hydrotherapy has been used as a healing method for as far back as we can tell. Using water at varying temperatures boasts impressive benefits to multiple organ systems in the body, (R) but in this post I'd like to spend a little time focusing on the cold!
Ice-bathing, cold showers, and cryotherapy all impose a form of stress on the body called hormesis which forces an adaptive response by cells throughout the body (R). This stress response is in many ways beneficial, ultimately activating gene pathways involved in rejuvenation. (In a previous post, I’ve covered some of the beneficial effects of sauna use, which works in a similar way, albeit at the other end of the temperature spectrum.)
Read on to discover the many ways cold showers can increase brain function, reduce pain, enhance your immunity, reduce recovery time and even help you lose weight!
DISCLAIMER: While intermittent cold showers and brief periods of cold-water immersion might be safe (and beneficial) for the general population, if you are on any medications or have any medical condition, make sure your doctor approves your use of cold water hydrotherapy. This post is meant to inform and educate—it is not a replacement for medical advice and should not be construed as such.
1. Cold showers may be a potential treatment for depression.
Cold water showers have the potential to impact your mental health. One hypothesis is that primates have experienced physiological stressors including brief changes in temperature for millions of years and today, our lack of such “thermal exercise” may be to the detriment of our brain function. (R)
Cold water therapy has been shown to increase synaptic release of norepinephrine and raise blood levels of beta-endorphin and norepinephrine (R). Endorphins are our happy little hormones associated with a sense of well-being while norepinephrine plays a role in many cognitive processes that are important to maintaining social relationships. Social dysfunction is possibly one of the most important factors affecting the quality of life in depressed patients. (R)
Some interesting research has been done on the mood-enhancing effects of cryotherapy in patients with mood and anxiety disorders. In a controlled trial, 3 weeks of cryotherapy (cold exposure) caused 34.6% of people with mood/anxiety disorders to experience a decrease of at least 50% of depressive symptoms on a depression scale compared to 2.9% of a control group. 46.2% of the cryo group also experienced a decrease in anxiety symptoms of at least 50% on an anxiety scale compared to zero in the control group. (R) (While not directly comparable to cold showers, I'm inclined to believe that cold showers confer at least some of the benefits of cryo. For the record, I've experimented with cryotherapy, cold showers, and cold water immersion, and have felt very similar effects on my mood from all three.)
The best part? There are no known long term side effects or withdrawal symptoms if you choose to include cold water therapy as one of your tools to combat depression or simply enhance your mood.
2. They can reduce inflammatory pain.
If you suffer from joint aches and pains or sore muscles, cold water therapy should be at the top of your list for pain relief.
The skin has an extremely high density of cold receptors that when stimulated, fire electrical impulses from peripheral nerve endings in our brain causing an analgesic, or pain-relieving, effect (R).
In one Finnish study, subjects suffering from inflammatory arthritis were subjected to cold mist showers twice daily for 2 minutes over the duration of 5 days. At the end of the trial period subjects reported a significant decrease in inflammatory arthritic pain (R). Cold water therapy has also been shown to relieve musculoskeletal pain, including knee and lower back pain (R) as well as relieving painful symptoms associated with fibromyalgia (R).
3. They can help you burn fat... with fat!
Humans have brown adipose tissue (brown fat) and white adipose tissue (white fat). Brown adipose tissue is thermogenic, meaning it produces heat. And, the more you have, the more heat you can produce. Brown adipose cells have many mitochondria which are the powerhouses of energy production in our bodies. Exposure to cold temperatures increases serum triglyceride uptake by our brown adipose tissue to be used as energy, meaning you’re literally burning fat (R)! When the sympathetic nervous system is stimulated as it is with cold water therapy, the brown adipose tissue dissipates the energy made as heat throughout your body (R).
Research has shown that cold acclimatization can significantly increase brown adipose tissue (R). Brown fat not only fights obesity, it slows the aging process, reduces the risk of degenerative disease and has an increased ability to uptake glucose with cold water stimulation (R).
4. They can increase circulation.
Taking the plunge into cold showers improves circulation. Naturally when we are exposed to cooler temperatures, our body’s blood vessels contract, known as vasoconstriction. This increases blood pressure and circulation. Warmer temperatures allow for vasodilation, the dilation of our blood vessels leading to a drop in blood pressure. This alternating hot and cold temperature allows the body to drive oxygen rich blood into areas that may not have as much blood supply when we are constantly “comfortable” (R). This method of improving blood circulation may have a tonic effect on blood vessel walls, strengthening them over time.
The benefits reaped in the circulation department aren’t simply unique to the cardiovascular system either. Our lymphatic system doesn’t have a pump and relies on muscular contractions and movement for flow to occur. Our lymphatic system is our immune powerhouse, carrying away waste and killing foreign invaders. The whole body contractions experienced during cold showers increases lymphatic flow.
5. They can improve memory function.
Studies have shown that cold water therapy can also improve memory. This is due in part to the robust increase in the neurotransmitter norepinephrine, which plays a key role in executive functioning regulating cognition, motivation, and intellect. The battery of positive “nootropic” effects (R) doesn’t end there: Cold water exposure can cause a significant decrease in tension and fatigue, and you are already aware of its potential to elevate mood. The ability of cold water to reduce stress may be a key mechanism by which it can improved memory.
Finally, cold water's positive effects on circulation can also help memory as this occurs not only below the neck but in the brain as well. (R)
6. They can shorten exercise recovery time.
Delayed onset muscle soreness is something many of us experience days after a workout. Leg day is the worst, when 24-48 hours later, the simple act of sitting makes you cringe. When we work our muscles, we create micro tears which are then repaired allowing for muscle growth. This process may cause inflammation contributing to sore muscles and a painful recovery. Because of the anti-inflammatory effect of cold water therapy in part due to vasoconstriction, it has been shown that cold showers can actually speed up this healing process (R). So next time you start feeling the pain, hop in a cold shower so you can do it all over again sooner!
7. They can stimulate and strengthen your immune system.
Cold stress exposure can boost your immune system. Not only will cold showers increase endogenous antioxidant production (R) but the number and activity of immune cells have also been shown to proliferate (R). Peripheral cytotoxic T-lymphocytes and natural killer cells shown to increase play a major role in adaptive and innate tumor immunity. Plasma levels of tumor necrosis factor-α, IL-2 and IL-6 have also been shown to be mildly increased with cold stress over the period of 5 days to 6 weeks (R). It is suggested that this increase in proinflammatory cytokines and interplay with hormones is what leads to the body’s adaptive response to restore immune homeostasis (R).
In one study involving hundreds of participants, cold shower treatments significantly decreased sick days over a 90 day period by 29% (R)!
So what does all this mean? Don’t stay warm to avoid catching a cold.
Tips to get started
1. Work your way down.
Many studies show benefits attributed to cold water showers with as little as 2 minute exposure times. If you’re wary about turning the knob too far right at first, you can allow your body time to adapt by starting off as you normally would and finishing the last 2 minutes of your shower cold.
2. Or, jump right in!
Slowly easing into cold showers may be necessary for some, but jumping in may be right for you. Cold shock is attributed with an involuntary increased heartbeat and rapid breathing, but is coupled with its own benefits. This cold shock phenomenon has been shown to decrease the habituation period and the colder the better. Jumping in at 50°F has been shown to improve adaptation more so than dipping your toes in at 59°F (R).
3. Increase time intervals while decreasing temperature.
As your body adapts to cold showers, begin to increase exposure time and decrease temperature. If you start off with 2 minutes at the end of the shower, gradually increase it to 3, then 4 and so on until you can handle the cooler temperatures for the entirety of your shower. As your increase duration, decrease temperature. If you start off at 60°F, gradually work your way down, targeting 50°F.
4. Measure your temperature.
The ultimate goal would be to get your water temperature down to about 50°F, or 10°C. An easy way to know how cold your shower is would be to simply get a plastic cup and a thermometer. At the peak of coolness, grab a water sample with your cup, drop in the thermometer and voila!
Thanks for reading! Is this something you think you might add to your healthy lifestyle bag of tricks? Let me know in the comments below your experiences with cold showers!
Written with contributor Katie Bigras