Cold water shock and swimming abroad

If you grow up swimming in the warm Gulf, the sea or a lake in the UK or Europe can be a real shock, even in summer. Knowing what cold water does to your body, and how to respond, could save your life at university or on holiday.

What cold water shock is

• The RNLI describes cold water shock as the body's short-term, involuntary response to sudden immersion in cold water, and calls it a leading cause of death around UK coasts.
• The UK National Water Safety Forum treats anything at or below 15 degrees Celsius as cold water.
• The RNLI says water around Scotland's coast and inland waterways rarely gets far above 10 degrees Celsius, even when the air is hot.
• It causes you to gasp for air and thrash around, and immediately puts you at risk of sinking (RNLI).
• The RNLI says the worst effects pass quite quickly, within about 60 to 90 seconds; the National Water Safety Forum says cold water shock normally lasts up to 3 minutes.

Float to Live

• Resist the urge to thrash or swim hard (RNLI).
• Lean back, spread your arms and legs, keep your chin up and your airway open (RNLI).
• Gently scull with your hands if you need to (RNLI).
• Hold this for about 60 to 90 seconds while your breathing settles.
• Then calmly swim to safety, call for help or keep floating until help arrives.

Lakes, rivers and quarries

• The National Water Safety Forum warns that quarries and reservoirs can be deceptively deep and cold all year.
• Rivers can have weirs and fast-flowing water; avoid areas near run-off, livestock and estuaries because of pollution (National Water Safety Forum).
• RLSS UK warns that cold water shock, pollutants, currents, debris and fast-flowing water can catch out even experienced swimmers.
• Choose lifeguarded beaches or supervised open water venues. Local clubs often know the safer spots (National Water Safety Forum).
• If you do swim outdoors, wear a well-fitting wetsuit and enter slowly to let your body adjust (National Water Safety Forum).

On holiday and abroad

• RLSS UK advises checking whether lifeguards are on duty, learning what local flags and signs mean, and knowing who to call in an emergency.
• RLSS UK warns against using inflatables in open water, because people on inflatables are blown out to sea.
• Flag systems differ by country. In the UK the RNLI says swim between the red-and-yellow flags.
• In the UK, call 999 or 112 and ask for the coastguard at the coast (RNLI). Look up the local emergency number before any trip.
• Tell someone where you are going and when you expect to be back, and carry a way to call for help (National Water Safety Forum).

University and social situations

• RLSS UK's Water Safety Code: stop and think, stay together, never swim alone, and only swim where there is a lifeguard.
• Never jump into rivers, docks or canals on nights out, however hot the day has been.
• Alcohol and water do not mix: public health guidance links alcohol to a higher risk of drowning.
• If a friend is in the water, do not follow them in. Call, throw something that floats, and tell them to float.