A dozen people have died so far this summer swimming in open water across the UK, prompting urgent warnings about the dangers of cold water shock. Temperatures remain above average for much of the country after a record-breaking spell of hot weather, with a yellow heat health alert still in force for eastern and South East England and London until 8pm on Saturday.
What is Cold Water Shock?
Cold water shock is the body's natural physical reaction to sudden immersion in cold water. The response is immediate and can lead to drowning, according to the National Fire Chiefs Council (NFCC). Anyone who suddenly enters cold water—whether by accident or by jumping in—is at risk, regardless of their swimming ability.
What Happens During Cold Water Shock?
The National Water Safety Forum (NWSF) explains that cold water shock causes gasping, panic, and loss of swimming ability, all of which can lead to drowning. It also triggers a spike in heart rate and blood pressure, which may result in a heart attack, even in fit and healthy individuals.
How Cold is UK Water?
Many inland waters in the UK remain at 16°C or below even in summer—a temperature considered hazardous for cold water shock, according to the NWSF. The RNLI notes that even on a hot day, water can be cold. Average UK and Ireland sea temperatures are around 12°C, and rivers such as the Thames are colder. Water temperature depends on location, depth, stirring, and flow, and can take many weeks to warm up, says Professor Mike Tipton, chairman of the NWSF. Sea water around the UK, for example, does not reach its warmest until late August or early September.
How to Stay Safe
The NWSF and Respect The Water have launched a new safety campaign called Phone Float Throw. It provides bystanders with instructions on how to help someone struggling in the water without putting themselves in danger: Phone 999 to get help; Tell the person to stay calm and float on their back; Throw rescue equipment to help them float until emergency services arrive.
