Whole-body cryotherapy (WBC) involves exposing the body to extremely cold, dry air, typically ranging from -110°C to -160°C (-166°F to -220°F), for a short duration, usually two to four minutes. This non-invasive therapy aims to trigger the body’s natural physiological responses to cold. This article explores the body’s reactions to such extreme temperatures and addresses concerns regarding cryotherapy’s potential effects on the heart, providing clarity on associated risks.
The Body’s Response to Extreme Cold
When the human body encounters extreme cold, it initiates physiological responses to conserve heat and protect vital organs. Cold receptors in the skin rapidly detect the temperature drop, sending signals to the brain and triggering the sympathetic nervous system, which prompts immediate adjustments to maintain core body temperature. One of the primary responses is peripheral vasoconstriction, where blood vessels in the extremities narrow significantly. This action reduces blood flow to the skin’s surface, redirecting warmer blood toward the body’s core to minimize heat loss. Involuntary muscle contractions, known as shivering, also commence as the body attempts to generate additional heat through increased metabolic activity. These coordinated reactions are part of the body’s natural defense mechanisms against cold exposure.
Cryotherapy’s Impact on the Heart and Blood Vessels
The extreme cold temperatures encountered during whole-body cryotherapy induce distinct changes within the cardiovascular system. A pronounced vasoconstriction occurs, leading to a significant narrowing of peripheral blood vessels. This widespread constriction increases peripheral resistance, which is the resistance blood encounters as it flows through the circulatory system.
As peripheral resistance rises, the heart must work harder to pump blood, which can result in an elevation of blood pressure. Studies have shown a temporary increase in both systolic and diastolic blood pressure during and immediately after cryotherapy sessions. Concurrently, the heart rate may also increase, reflecting the cardiovascular system’s effort to adapt to the sudden cold stress. While these are typical physiological adjustments for healthy individuals, they can place considerable strain on the heart, particularly for those with pre-existing cardiovascular conditions.
Who Should Avoid Cryotherapy?
Certain medical conditions are contraindications for whole-body cryotherapy, particularly those affecting cardiovascular health. Individuals should avoid cryotherapy if they have:
A history of heart attack (myocardial infarction), especially within the last six months, due to the potential strain on the heart.
Experienced a stroke.
Uncontrolled high blood pressure (hypertension, typically above 160/100 mmHg), as cold-induced vasoconstriction can further elevate blood pressure.
Conditions impacting circulation, such as severe peripheral artery disease, deep vein thrombosis (DVT), or Raynaud’s phenomenon, as cryotherapy can worsen restricted blood flow to extremities.
A cardiac pacemaker or other cardiovascular implants.
Unstable angina pectoris, symptomatic cardiovascular disease, or certain cardiac rhythm disorders.
Prioritizing Safety Before Cryotherapy
Before considering whole-body cryotherapy, consulting with a healthcare professional is important. An individualized assessment of one’s medical history and current health status can help determine suitability for the treatment. Disclosing all pre-existing conditions, medications, and any concerns is a necessary step in this process. Choosing a reputable cryotherapy facility is also important. Such facilities typically employ trained staff who adhere to strict safety protocols, including proper equipment maintenance and emergency procedures. During a session, it is important to listen to one’s body and immediately communicate any discomfort or adverse reactions to the attending staff. These precautions help ensure a safer experience.