Cryotherapy involves the therapeutic application of intensely cold temperatures. This approach utilizes extreme cold to activate the body’s natural responses, contributing to various wellness and medical applications.
Typical Temperature Ranges in Cryotherapy
Cryotherapy encompasses various applications, each utilizing distinct temperature ranges to achieve its intended effect. Whole Body Cryotherapy (WBC) typically involves exposing the body to air temperatures ranging from approximately -110°C to -160°C (-166°F to -256°F) for short durations, usually two to three minutes. Some systems can reach even lower temperatures, down to -180°C or -240°F.
Localized cryotherapy, which targets specific areas of the body, can involve similar or sometimes even colder temperatures at the point of application. These targeted treatments might use temperatures between -20°C to -30°C (-4°F to -22°F) for air-pulsed systems, or as low as -100°F to -150°F (-73°C to -101°C) for more direct applications.
Cryosurgery, also known as cryoablation, employs extremely low temperatures to freeze and destroy unwanted tissues, such as abnormal cells or warts. For this medical procedure, liquid nitrogen is commonly applied directly to the target tissue. Other cryogens used in cryosurgery include carbon dioxide snow at -78.5°C (-109.3°F) and a mixture of dimethyl ether and propane at -57°C (-70.6°F).
Methods of Achieving Cryogenic Temperatures
The extreme temperatures used in cryotherapy are achieved through specialized substances and systems. Liquid nitrogen is a widely used cryogen, particularly in whole-body cryochambers and handheld devices for localized treatments. It generates very low temperatures, with its boiling point at -196°C, and cools the air inside chambers or is applied directly via probes or sprays.
Electric cooling systems offer an alternative method for generating cold temperatures, often found in newer whole-body cryochambers. These systems utilize refrigeration units or a combination of cooling elements to achieve temperatures that can reach around -110°C (-166°F) or -150°F (-101°C). Unlike nitrogen-based systems, electric chambers do not require cryogen refills and typically produce a breathable environment.
Other cryoagents are employed for specific medical applications. Argon gas is sometimes utilized in cryosurgery to achieve the necessary freezing temperatures for tissue destruction. Carbon dioxide, often in the form of “snow,” can also be used in localized cryotherapy, providing optimal cooling at temperatures around -78°C (-108°F) for targeted treatments.
How the Body Reacts to Extreme Cold
When exposed to the extreme cold of cryotherapy, the body initiates several physiological responses.
An immediate reaction is vasoconstriction, where blood vessels in the skin and extremities narrow to redirect blood flow toward the body’s core, helping to maintain core body temperature. Upon exiting the cold environment, the blood vessels then widen in a process called vasodilation, increasing blood flow back to the peripheral tissues. This alternating constriction and dilation can enhance circulation and facilitate the removal of metabolic waste products.
The intense cold also affects nerve activity. Cold temperatures can numb nerve endings, which helps reduce pain signals and decrease sensitivity in the treated area. This reduction in nerve conduction velocity contributes to the pain-relieving effects of cryotherapy.
Exposure to cold can influence the body’s metabolic processes. The short, controlled exposures in cryotherapy typically prompt the body to increase its metabolic rate to generate heat. This can involve shivering and the activation of brown adipose tissue, which burns calories to produce warmth.
Cryotherapy helps reduce inflammation. The decreased blood flow due to vasoconstriction can limit the accumulation of fluid in tissues, thereby alleviating swelling. Cold exposure also appears to decrease the production of inflammatory substances in the body, contributing to an overall reduction in inflammatory responses.