Take care: Heat sources can burn or scald, sub-zero temperatures can damage tissue, sudden changes in posture can cause dizziness or fainting, and wet surfaces can be slippery.

Extreme temperatures can be hazardous. Special care needs to be taken near very hot water, heating elements, and steam to avoid burns or scalding. Tissue damage, including frostnip or even frostbite, can also occur from cryotherapy chambers or ice baths that have excessive salt that lowers the freezing point of water to sub-zero temperatures.

While exposure to extremes of hot and cold can cause direct harm, the most common adverse events from contrast bathing are due to faints, falls, and funny turns caused by sudden changes in posture and/or slippery, wet surfaces. If you stand up suddenly after a hot bath or sauna, gravity will pull blood away from your head and into the dilated vessels in your legs, making you dizzy, lightheaded, or faint. To avoid this, it is best to take your time when getting up and practice sitting for a few seconds before standing up slowly. It is also prudent to take extra care with wet or slippery floors and to hold onto a wall or rail to steady yourself and ensure your blood pressure has stabilised before taking a first step.

Taking care with extreme temperatures is particularly important for people with peripheral neuropathy, autonomic neuropathy, and vascular or other conditions that reduce adaptation to temperature extremes. Extra care also needs to be taken by people with heart conditions such as irregular heartbeats or those with myocarditis or pericarditis, as the sudden release of adrenaline caused by the shock of extreme temperatures can lead to potentially fatal arrhythmias in some people.

Tune in: Enjoy ‘forced mindfulness’ induced by temperature extremes and relaxation induced by thermal comfort.

While extreme temperatures can be potentially life-threatening, saunas and ice baths provide the opportunity to fully control your exposure to thermal stress and practice being calm and composed while under physical duress. This helps cultivate physiological and psychological resilience and navigate the uncertainties of daily life. One of the great benefits of contrast bathing is the ‘forced mindfulness’ that arises when the physiological stress caused by temperature extremes builds up until it demands your full attention.

To ensure you achieve the benefits of physiological stress while remaining within safe physiological limits, it is best to start with milder temperatures and slowly increase your exposure while tuning in to your body and breathing calmly so that you do not feel overwhelmed.

Staying in control is especially important for people with a history of anxiety or PTSD, as sudden cold exposure naturally causes gasping and hyperventilation and reproduces the breathing pattern and blood chemistry of anxiety and panic, which can be distressing if you are not adequately prepared. Temperature extremes provide the opportunity to recreate these feelings in a controlled environment and overcome them.

There are a number of biohacking tools that can help cope with stressful temperature extremes. For example, the "Ten Hacks to Relax” are physical actions that activate your parasympathetic ‘rest and digest’ response and help to convince your body that you are in control. These actions, which can be done anytime you are scared, anxious, upset, or in pain, can serve as emotional first aid and assist in extreme or overwhelming situations such as being in an ice bath, sauna, or extremely hot bath.

The aim of contrast bathing is to give you the ability to induce physiological stress while maintaining control over your situation. You should therefore never let anyone coerce or pressure you into contrast bathing or staying in an uncomfortable situation longer than you want to. You also need to ensure that you can easily remove yourself from extreme temperatures and find a place to rehydrate, rest, and recover.