Cryotherapy is a therapeutic application that uses ultra-low temperatures to trigger beneficial physiological responses in the body. It involves intentionally exposing the body to an environment far colder than any natural condition. The goal is to rapidly cool the skin’s surface temperature, initiating a systemic reaction that helps with muscle recovery, pain relief, and reduced inflammation. This dramatic temperature drop is a core component of the treatment, distinguishing it from traditional ice baths or cold compresses.
The Specific Temperature Range
Whole Body Cryotherapy (WBC) chambers operate within an extreme temperature range, typically between -110°C and -140°C (-166°F and -220°F). Some devices can reach even lower ambient air temperatures, sometimes approaching -180°C (-292°F). This measurement reflects the air temperature inside the chamber, not the internal core temperature of the body. The short duration of the session is designed to prevent the core temperature from dropping significantly. The extreme cold air causes the skin surface temperature to rapidly decrease to around 5°C to 10°C (41°F to 50°F), stimulating the body’s cold-shock response.
Methods Used to Achieve Extreme Cold
Liquid Nitrogen Systems
The ultra-low temperatures required for WBC are achieved through two primary technological methods. The most common method involves the use of liquid nitrogen, which is stored in a tank and then vaporized into the chamber or cryosauna. As the liquid nitrogen expands into a gas, it absorbs heat from the surrounding air, creating the hyper-cooled environment. The patient is exposed only to the super-chilled air, as the liquid nitrogen itself is contained and does not directly touch the skin.
Electric Refrigeration Systems
A second, increasingly available method uses advanced electric refrigeration systems, also known as electric cryo-chambers. These systems function much like commercial freezers but are engineered to reach sub-zero temperatures comparable to the nitrogen-based chambers. Electric systems use refrigerated cold air to cool the environment, eliminating concerns about exposure to nitrogen gas, which can pose a risk in poorly ventilated areas. While both methods achieve the necessary cold, electric systems often operate at the upper end of the temperature range compared to the coldest nitrogen units.
Whole Body vs. Localized Differences
Whole Body Cryotherapy
Cryotherapy is applied differently depending on whether the entire body or a specific area is being targeted. Whole Body Cryotherapy involves stepping into a chamber where the ambient air temperature is homogeneously cooled to the extreme sub-zero range. The cold environment surrounds the entire body, causing a widespread vasoconstriction response across the skin’s surface. The temperature reading is a measurement of the overall cabin environment.
Localized Cryotherapy
Localized cryotherapy uses a handheld device to direct a concentrated stream of super-cooled air or gas onto a small, specific area, such as a sore knee or shoulder. This method often uses a jet of nitrogen vapor or pressurized carbon dioxide gas, which is naturally around -78°C when released. The target is to rapidly reduce the skin surface temperature of the localized area to a range of about 4°C to 10°C (39°F to 50°F). This application allows for a more intense, yet highly controlled, cold shock on the targeted tissues.
Duration and Safety Limits of Exposure
Session Duration
The brief duration of cryotherapy sessions allows for therapeutic benefits without causing cold-related injury. A typical whole-body session is limited to a maximum of two to four minutes. This short exposure time is sufficient to trigger the desired physiological response of rapid surface cooling and subsequent vasoconstriction. Exceeding this window increases the risk of adverse effects like frostbite or thermal injury.
Safety Protocols
Safety protocols mandate the use of protective gear for the body’s extremities, which are most vulnerable to cold damage. Patients must wear dry socks, slippers, and gloves to shield their hands and feet from direct contact with the extreme cold air. The operator must also monitor the session closely to ensure the client’s skin remains dry. Moisture would accelerate the cooling process and increase the risk of injury.