Whole-body cryotherapy (WBC) involves intentionally exposing the body to extreme cold for a short duration, usually for therapeutic purposes like muscle recovery or pain relief. During a session, a person steps into a specialized chamber or cryosauna and is subjected to ultra-low temperatures ranging from -110°C to -160°C (-166°F to -256°F) for two to four minutes. The intense cold triggers rapid vasoconstriction, diverting blood toward the core. Assessing the known hazards associated with this treatment is necessary to address the serious question of whether cryotherapy can be fatal.
Understanding Whole Body Cryotherapy
Whole Body Cryotherapy involves standing in a column-like device or a walk-in room that is rapidly cooled to sub-zero temperatures. Chambers use one of two primary methods: liquid nitrogen (LN2) or electric cooling. Nitrogen-cooled units, often called cryosaunas, are typically open at the top, allowing the user’s head to remain above the cold gas and breathe room air.
Electric-cooled chambers are enclosed walk-in rooms that use refrigerated cold air without nitrogen. These electric systems generally reach temperatures closer to -110°C, while nitrogen-based systems can achieve temperatures as low as -160°C. The goal is rapid, intense cooling of the skin surface to induce a systemic physiological reaction. This quick exposure to dry cold is distinct from an ice bath, which involves longer exposure to wet cold and cannot reach the same low temperatures.
Assessing the Direct Risk of Fatality
Fatalities directly linked to whole-body cryotherapy are extremely rare, but they have occurred, raising significant safety concerns. The danger is generally not from the cold itself, but rather from procedural and equipment failures. The U.S. Food and Drug Administration (FDA) has not cleared or approved any whole-body cryotherapy devices for treating specific medical conditions, citing a lack of evidence for the supposed health benefits and noting the potential for serious risks.
The FDA considers the use of these devices risky, especially since their efficacy for many advertised claims remains unproven by medical literature. The risk of death is almost entirely attributed to one specific mechanism related to the gas used for cooling. The seriousness of the potential outcome makes safety protocols non-negotiable.
The Primary Cause of Acute Danger
The acute and life-threatening danger in whole-body cryotherapy largely stems from the use of liquid nitrogen (LN2) as a coolant. LN2 vaporizes rapidly into a large volume of nitrogen gas, which is physiologically inert. Nitrogen gas is odorless and colorless, making its presence undetectable by human senses.
This gas poses a risk because it displaces breathable oxygen in the air, creating an oxygen-deficient environment. If nitrogen vapor accumulates in a poorly ventilated room or chamber, the oxygen concentration can quickly drop to dangerously low levels. Breathing an atmosphere with reduced oxygen, a condition known as asphyxiation, can lead to immediate unconsciousness after only a few breaths.
Fatal incidents have involved users lowering their head into the nitrogen-rich environment of the cryosauna or a leak causing gas buildup in an enclosed space. Since there is no warning sign like shortness of breath, a person can lose consciousness rapidly, becoming incapable of exiting the chamber. This systemic risk is unique to nitrogen-cooled systems and highlights the necessity of proper ventilation and constant supervision.
Serious Non-Lethal Complications and Injuries
Even when the procedure is non-fatal, whole-body cryotherapy carries the risk of serious complications requiring medical attention. The most common physical injury is localized frostbite, which can occur when skin touches the metal surfaces of the chamber or when the skin is not completely dry. Any moisture on the skin, such as sweat, will freeze instantly at these temperatures, increasing the risk of cold-related tissue damage.
The extreme cold can also cause cryo-burns, a form of severe localized injury resulting from inadequate protection or prolonged contact with the hyper-cold air. Users are required to wear protective gear, including gloves, socks, and slippers, to shield extremities from damage. Failure to wear proper protective eyewear can also lead to eye damage due to the intense cold.
The body’s acute response to the cold can induce temporary cardiovascular stress. The rapid and intense vasoconstriction, which is the narrowing of blood vessels, causes a temporary increase in blood pressure and can alter heart rate and respiration. This sudden change can be particularly hazardous for individuals with pre-existing heart conditions. Temporary side effects include skin redness, tingling, or numbness, which typically resolve shortly after the session ends.
Safety Guidelines and Who Should Avoid Cryotherapy
Mitigating the risks of whole-body cryotherapy depends on strict adherence to safety guidelines and a thorough screening process. Facilities must ensure that a trained operator constantly supervises the entire session, remaining present to monitor the user and control the chamber. Treatment sessions must be strictly limited to a maximum of three or four minutes to prevent excessive exposure.
Clients must ensure their skin and clothing are completely dry before entering the chamber, and they must wear mandatory protective gear for their hands, feet, and ears. A consultation with a healthcare provider is prudent for anyone with a chronic health issue before beginning cryotherapy.
Absolute Contraindications
Individuals with certain medical conditions should avoid whole-body cryotherapy due to the potential for severe adverse reactions.
- Pregnancy.
- Severe hypertension (blood pressure over 180/100).
- Recent heart attack or stroke.
- The presence of a cardiac pacemaker.
- Circulatory disorders, such as deep vein thrombosis or Raynaud’s syndrome, as rapid vasoconstriction could worsen the condition.
- A known cold allergy or uncontrolled seizures.
- Severe anemia.