The body has built-in thermoregulatory processes geared towards keeping body temperature in normal range and promoting overall homeostasis. The hypothalamus, a structure found deep within the center of the brain, is at the root of the body’s effort to regulate temperature. Often compared to a control center or thermostat, the hypothalamus regulates processes that maintain an internal balance in the body, including blood pressure, hunger and thirst, mood, sleep, and body temperature.
The hypothalamus is also an important connection between the body’s endocrine and nervous systems. The hypothalamus communicates with neurons to take in information about changes and disruptions to the body’s internal state. In response to these signals from the nervous system, the hypothalamus will trigger the production or release of hormones that take action in the body to support a return to homeostasis.
When the body is exposed to heat, the hypothalamus kickstarts processes that work to lower the core temperature back to within a degree or two of the average. This includes stimulating the sweat glands to produce sweat on the skin’s surface, where evaporation and cooling can occur, and dilating blood vessels so blood can rush to the skin’s surface, where heat transfer with the external environment can occur.
The hypothalamus is also at work when the body experiences cold. The body’s response to cold includes opposing processes to those involved in heat exposure designed to prevent heat loss rather than encourage it. The hypothalamus sends hormonal signals that promote shivering to boost heat production and the constriction of blood vessels to redirect blood flow away from the skin’s surface and prevent heat loss.
While these bodily responses to extreme temperature exposure are naturally in place to manage changes to homeostasis, recent research suggests that they can, in some instances, be used to one’s advantage in promoting recovery and boosting physical and mental performance.
In this article, discover more about how this can be achieved through cold therapy.
Cold therapy is a method of putting cold exposure to therapeutic use. It makes the most of the body’s innate response to cold temperatures by inducing cold exposure in a controlled setting. As soon as the cold receptors in the skin register a cold environment, they send a signal to the hypothalamus, which incites a cascade of signaling and hormonal production that has wide-ranging effects on the body.
These hormonal signals clearly represent the interaction between the endocrine and nervous systems. Hormones released by the hypothalamus include the stress hormone cortisol, which triggers activation of the body’s sympathetic nervous system (also known as the fight-or-flight response).
As a result, blood vessels constrict and divert blood flow to key areas, including the heart and vital organs. Norepinephrine increases, resulting in initial heart rate and blood pressure increases. The muscles contract to induce shivering. The body’s stores of brown fat are also activated.
The body’s most common type of fat is white fat, which provides energy storage and protective insulation of the organs. Brown fat is present in the body in smaller quantities and functions differently. While it also stores energy, the primary purpose of brown fat is to spring into action during cold exposure to help prevent heat loss and keep the body warm. During cold exposure, brown fat burns its stored energy to stimulate heat production and raise body temperature.
Cold exposure doesn’t just stimulate the sympathetic nervous system. It also triggers the parasympathetic nervous system. After an initial period of shock in which the fight-or-flight response is activated, the body can adapt to the cold.
As this process occurs, the sympathetic nervous system’s response begins to decline, while the parasympathetic nervous system starts to take over as the vagus nerve is stimulated. Accompanying effects in the body include drops in heart rate and blood pressure and the release of endorphins and other neurotransmitters that positively impact mood and feelings of well-being.
Cold therapy can be a beneficial addition to your regular wellness routine. There are several types of cold exposure that you can try out to take advantage of the benefits of cold therapy for yourself.
In its simplest form, cold therapy could involve applying a cold compress or ice pack to a sore body area after an intense workout. There are more advanced versions of cold therapy that have become popularized in recent years that extend the positive impact of cold exposure to the entire body. These include:
Ice baths are one of the most common types of cold therapy. Typically, ice baths involve filling a tub about halfway with cold water and between one to three bags of ice to maintain a temperature range of 50-59°F.
The maximum amount of time anyone should spend in an ice bath is 15 minutes, but you can start off by spending just a few minutes in the tub and working your way up in small increments in subsequent ice baths as your body adjusts to the experience. Ice baths are often used as a post-exercise recovery strategy. In this case, they are considered most effective when taken half an hour or less after finishing a workout or sporting event.
Cold showers are one of the simplest forms of cold therapy and one of the easiest to add to your daily routine. Cold water doesn’t need to be used for the entirety of a shower to make it a practical cold therapy experience. Incorporating two to three-minute periods of exposure to water temperatures lower than 60 degrees during a shower is sufficient to qualify as cold therapy and can be a refreshing way to finish a shower. You can begin with just 30-second cold water periods and work your way up over time as your body gets used to withstanding more prolonged exposure to the cold.
During a cold plunge, the entire body is submerged in cold water — typically in a tub or tank in a dedicated cold plunge facility. These tanks are usually kept in the same temperature range as an ideal ice bath (between 50-59°F, but it could be colder depending on the facility).
Between 10 and 15 minutes of exposure in a cold plunge is ideal, but participants are encouraged to begin with shorter durations and work their way up to longer cold plunges for the best results.
Whole-body cryotherapy offers a more intense experience of cold exposure. It can only be performed in a specialized cryotherapy center. These facilities are equipped with specialized cryotherapy chambers that get down to between negative 200–300°F. Typically, users spend between two and four minutes in the chamber. During this time, the entire body is subjected to an extreme drop in temperature, aiming to stimulate the body’s natural response to cold exposure.
Research into the benefits of cold therapy suggests that there are many reasons it’s a worthwhile addition to your healthy lifestyle. Some of the cold therapy benefits that researchers have identified include:
Research indicates that cold exposure can stimulate the immune response and boost the body’s immune system. In one study, participants adopted a cold shower routine for 30 days. Cold showers were associated with a 29% decrease in sickness absence from work. Exposing the body to cold temperatures can activate the circulation of white blood cells, which are responsible for fighting infections and play a large role in the immune response.
Cold therapy has been proposed as a possible treatment method for mental health conditions, including anxiety and depression, and a valuable stress-relief activity. Cold exposure triggers the release of a variety of chemicals in the body that can contribute to improved mental health symptoms.
The neurotransmitter norepinephrine involves cognitive processes, including attention, focus, and mood. Endorphins can also be released, which contributes to feelings of well-being. Early research has found that cold therapy can reduce the experience of depressive symptoms.
Subjecting your body to frigid temperatures puts the circulatory system to the test, which can improve overall circulation. Cold exposure drives blood flow to the core to protect the organs. It also tasks the heart with working hard to provide oxygenated blood to the areas of the body that need it the most. The strain put on the body by cold temperatures increases blood flow and can improve the efficiency of the circulatory system.
Cold therapy induces a drop in the temperature of the skin surface and outer muscle groups and slows down associated metabolic processes. Blood flow to these areas is minimized as the heart pumps blood to the core. As the blood vessels constrict to redirect blood flow, swelling and inflammation in the tissues of the muscles are reduced. After a cold therapy session is finished, rich, oxygenated blood flows back from the core to the extremities, bringing blood with a high nutrient and oxygen content to the muscles, which can help boost post-workout recovery.
Cold therapy is gaining popularity as a pain relief strategy for exercise-related muscle soreness and chronic pain alike. The same process of reduced blood flow to the skin and surrounding muscles that reduces inflammation during cold therapy can also decrease feelings of pain in those areas. It has also been suggested that cold therapy can mitigate pain perception by interfering with pain signals sent to the nervous system, leading to lessened experiences of pain and discomfort.
Cold therapy is one of the top five most common recovery activities WHOOP members track. The WHOOP app allows you to log your recovery efforts after a grueling workout, whether in the form of meditation, stretching, yoga nidra, massage therapy or cold exposure through cold showers and ice baths. With WHOOP, you can gain actionable insight into the benefits of cold therapy on your own recovery and potential future performance.
Rely on WHOOP to give you the insight you need to make cold therapy an effective addition to your routine.
