Dubai: A sweeping global fund-raising movement may be raising a lot of money for charity.

But it could, in limited circumstances, be harmful to the health of people with underlying medical conditions, say health experts in the UAE.

Following the recent death of UK teenager Cameron Lancaster linked to his taking the challenge, some are also questioning the health risks involved.

While it has raised approximately $70 million (Dh257.12 million) for Amyotrophic Lateral Sclerosis (ALS), the challenge could be harmful for some fundraisers whose bodies may not welcome the shock of cold icy water.

"It cannot actually kill a person but it is not advisable as the body goes into a cold shock response,” says Dr Sonia Gupte, GP at the Icare Clinics, Dubai.

Dr Gupte elaborated on how our physiology responds to it: “The cold shock response is the body’s reflex reaction to a sudden change in temperature. The human body’s normal temperature is about 37C or 98.6F. When the nerves sense the extreme cold and send a message to the brain, it goes into survival mode. Therefore, the blood supply is reduced, muscles contract, heart rate goes up as more oxygen is pumped into the blood and the affected person gasps for air. While healthy people are able to acclimatise to the sudden change, those with chronic illnesses or heart conditions must avoid pouring ice water on themselves. It is specially contraindicated in cases of individuals suffering from uncontrolled high blood pressure, irregular heartbeat or arrhythmia as their body is unable to adapt to the cold shock. However, this is not as bad as being submerged in cold water which can be much more dangerous.”

Traditionally, ice water splashes are known to boost body metabolism and reduce inflammation.

However, Dr Gupte says there is a detailed science behind this.

“Even in cryotherapy that uses subzero chambers, there are specific guidelines that are followed and the individual is closely monitored,” she adds.

Kai Stubbe, a partner at Cryo-Health, Dubai, seconds that. “Water transports the temperature much faster than air. When a bucket of iced water is thrown on an individual, he can hyperventilate and not be able to breathe as there is an immediate drop in the temperature on the skin’s surface.

"You might be in a cold lake but it takes nearly half an hour for the body’s temperature to drop from 37C to 35C to cause an individual’s death, but the sudden dropping of iced water makes one go into shock and gasp for air and that proves fatal. That is why sports stars like Cristiano Ronaldo and Kobe Bryant are opting for cryotherapy instead of iced baths to heal sports injuries where the temperature is much lower but the chamber is dry and it has a huge healing effect.”

Meanwhile, Ravshan Abitov, the Dubai-based convenor of a collective ice bucket challenge planned for Friday at Kites Beach in Dubai, has made sure there are no injuries when Dubai residents take the challenge.

“We are not using iced water. Instead we are using ocean water which will be warm at 8am. So there is no question of anyone being harmed by it. Water is a scarce commodity and we do not believe in wasting it. The idea is to stand up and show solidarity for a global cause. We have modified it so that it does not hurt our harm our resources or anyone,” he says.

So far 308 residents have signed up for the challenge in Dubai.