A Guide to Coldwater Safety

Introduction

Though the risk of hypothermia is present in long-term immersion, the majority of open water immersion deaths happen rapidly, often within the first three minutes. The single most dangerous element of open water swimming is Cold Shock. This is a rapid, involuntary physical reaction (gasping, racing heart) that peaks immediately upon entering cold water (within the first 30 seconds). The following safety guide is based on expert research from Professor Mike Tipton and colleagues, developed to directly address the sharp increase in cold water immersion accidents and fatalities seen across the UK.

Actionable Entry Steps

• Enter Gradually: Do not jump or dive in. Slowly wade into the water.
• Allow Cold Shock to Abate: Wait for the initial shock and uncontrollable breathing response to subside before swimming or immersing your face. This period should be at least 30 seconds.
• Breathe Control: Focus on controlling the urge to gasp by practicing slow, rhythmic breathing. Avoid prolonged breath holds.
• Float First: If you get into difficulty, don’t panic. Float on your back and move your arms and legs only as much as needed to stay on the surface, make sure you practice this. Doing this then gives you the chance to get your breathing back under control.

Before the Swim

• Know Your Risk Factors: Conditions like hypertension, cardiac rhythm disturbances, unstable asthma, and a family history of sudden cardiac death increase your risk during Cold water immersion. Up to 43% of drownings are associated with pre-existing medical conditions (Durine et al., 2022)
• Avoid Concurrent Stresses: Do not swim when acutely injured, exhausted, or if you have an acute exacerbation of a chronic medical condition.
• Medication & Alcohol: Certain prescribed medications (e.g., those with proarrhythmic risk), as well as alcohol and recreational drugs, are associated with fatalities as they can alter your cold response and perception.

Equipment & Location

• Swim with Others: Always swim on a lifeguarded area or with experienced others.
• Nominate a Safety Officer: If no formal lifeguard supervision is available, designate a safety officer.
• Wear Bright Gear: Use a visible hat (e.g., fluorescent) and a tow float for visibility.
• Analyze the Location: Critically assess the water for dynamic hazards like tides, currents, wind, temperature, sea/river state, debris, and pollution.

During & After Immersion

In the Water

• Go Incremental: Follow an incremental approach by starting when the water is warmest (e.g., mid-summer) and gradually habituate to the cold.
• Use a Wetsuit: Wearing a wetsuit will reduce the rate of cooling and increase buoyancy.
• Mind the Clock: Limit exposures to 10 minutes in colder water to avoid incapacitation due to muscle cooling.
• Don’t Trust Your Feelings: Never rely on how cold you feel (especially if you are cold-habituated), as this is dangerously unreliable.

On Exit (Rewarming)

• Dress Immediately: On exiting, wear warm clothing and a windproof outer layer.
• Rewarm Before Driving: Continued cooling occurs for approximately 30 minutes after you leave the water, so avoid driving during this period.

Sources:

• Durine, C. L., Sweet, J., & Clemens, T. (2022). The link between medical conditions and fatal drownings in Canada: a 10-year cross-sectional analysis. Canadian Medical Association Journal (CMAJ), 194(18), E637–E644.
• Tipton, M. J., Collier, N., Massey, H., Corbett, J., & Harper, M. (2017). Cold water immersion: kill or cure? Experimental Physiology, 102(11), 1335–13Many p55.
• Tipton, M., Massey, H., Mayhew, A., & Morgan, P. (2022). Cold water therapies: minimising risks. British Journal of Sports Medicine, 56(23), 1332–1334.