Temperature Exposure Safety: Cold Shock, Fainting and Burns

Urgent help comes first

If someone has collapsed, cannot be woken, is having trouble breathing, has chest pain, is confused after heat, or has been pulled from cold water, get emergency help right away. In the United States call 911 or the local emergency number. [1] Give rescue breathing and CPR if you are trained and they are needed. Heatstroke is a medical emergency. [2] This page is general information, not medical advice, and it does not give any recommended temperatures, times or routines, because there is no safe schedule that suits everyone.

Why this page exists

Cold plunges, ice baths, saunas, hot tubs and contrast routines are often presented as simple habits. Their short-term dangers are real and are rarely mentioned in marketing. This page covers the immediate risks. Risks tied to heart disease are in Temperature Exposure and Cardiovascular Conditions. Alcohol and drowning risks are in Alcohol, Dehydration and Water Safety With Temperature Exposure. Broader hydrotherapy safety is in Hydrotherapy Safety.

Cold shock

Cold shock is the body's automatic reaction to sudden contact with cold water. It can cause dramatic changes in breathing, heart rate and blood pressure. [1] The sudden gasp and rapid breathing alone create a greater risk of drowning, even for confident swimmers in calm water. [1] It can also cause panic that impairs clear thinking and decision making. [1]

A review of winter swimming reached a similar conclusion for people who are not used to it. It said unaccustomed individuals are at risk of death from the initial cold-shock response, from progressively worse swimming efficiency, or from hypothermia. [3] The same review noted that more prospective studies are needed to understand the short- and long-term health effects. [3] A life jacket significantly increases the chance of survival in unplanned cold-water immersion. [1]

Cold shock can happen in a lake, the sea or a river. Whether a tub or cold plunge at home carries the same risks was not covered by the sources read for this page, so no claim is made either way. Cold water in any setting still raises the possibility of gasping, panic and heart rhythm problems.

Hypothermia

Hypothermia is an abnormally low body temperature. It can make you sleepy, confused and clumsy, and it can happen from being under cold water for too long. [4] Because it affects thinking, the person may not notice it is happening. The British Heart Foundation advises avoiding cold-water swimming on your own and going with a friend or a group. [5]

Fainting

Fainting is a temporary loss of consciousness. [6] Heat or dehydration are among the causes. [6] A study of hot-tub bathing in older adults in Japan found that higher skin temperature during a bath went with higher systolic blood pressure and pulse rate. [7] A paper on alcohol and the sauna said large amounts of alcohol while sauna bathing may affect the body's ability to maintain blood pressure, and that the risk of a drop in blood pressure on standing, with fainting and accidents, is increased. [8]

Fainting in a sauna or bath is dangerous mainly because of what can follow. The same paper listed head injuries, heat stroke after passing out in a sauna, and drownings while swimming among the more serious accidents. [8] If someone faints, the person should stay lying down. [6]

Burns and scalds

Scalds from hot liquids and steam are among the most common causes of burns. [9] Burns can cause swelling, blistering, scarring and, in serious cases, shock. [9] A paper on alcohol and the sauna reported that sprains and burns are common minor accidents in the sauna. [8]

Heat illness

Heat stroke is a life-threatening illness in which body temperature may rise very high in minutes. [10] Medicines and alcohol can raise the risk of heat illness. [10] The same paper on alcohol and the sauna described heat stroke after passing out in a sauna. [8]

Who has more to lose

The sources read for this page and the linked pages point to extra caution for people with heart or blood-pressure conditions, older adults, people taking medicines that affect blood pressure or fluids, people who have been drinking, and anyone who feels unwell. Pregnancy and other conditions were not covered by the sources read here. Ask a doctor or pharmacist who knows your health history before trying these practices. Do not stop or change a medicine because of anything on this page.

How to think about it

• Do not do it alone when cold water or serious heat is involved. A companion can call for help.
• Stop and get out if you feel dizzy, confused, faint, short of breath or have chest pain, then get help if it does not pass.
• Treat marketing as marketing. Benefit claims are covered in Cold and Heat Exposure and Temperature Exposure and Longevity Claims.
• Breathing practices combined with cold water are discussed in Intensive Breathwork. This library does not give instructions for them.