The most effective method for treating heat stroke is immersing the body 25-degree water, while ice baths may be dangerous, according to Australian heat specialist, Doctor Nigel Taylor.
Other research has found that fanning the skin to encourage evaporative cooling, immersing the hands in cool water and wearing a cooling vest are all helpful heat illness prevention and cooling strategies, as is crushed ice ingestion.
However an ice bath is not more effective in treating potentially deadly exertional heat stroke (EHS) than bathing in 25-degree water according to Dr Taylor.
“When a hot person is placed in very cold water (say of about five degrees Celsius), skin blood flow is dramatically reduced, so heat loss is compromised,” he says, writing for the University of Wollongong.
Conversely, water of around 25 degrees Celsius increases heat dissipation by preventing this blood-flow suppression, according to Dr Taylor.
In fact, he says ice baths may actually be dangerous for those suffering exertional heat stroke or heat stress.
“Sudden cold immersion can result in significant and adverse physiological changes… and because hyperthermia elevates skin temperature, then the risk of cold shock in susceptible individuals is elevated,” Dr Taylor says in presenting his case to the American College of Sports Medicine.
“Why advocate such extreme cooling when less stressful cooling is equally effective, infinitely more comfortable, and less likely to elicit undesirable adverse effects?” he asks.
Bathing at Work Not Usually Feasible
Unless a worker is suffering potentially deadly heat stroke – when cool water immersion is critical to help save their life or minimise serious organ damage – convincing management to let workers down tools to take a bath mid-shift might be a tough sell.
Yet preventing heat illness in all its forms is critical for workplace safety and productivity, meaning strategies to prevent and treat it must be in place.
THORZT has previously discussed 11 strategies for preventing heat stress with cooling methods including PPE-free areas with fans to allow evaporative cooling, crushed ice ingestion and cooling apparel such as vests and neck ties.
Research: Which Cooling Strategy is Most Effective?
In 2009, four researches set about determining which of five cooling techniques are most effective after exercising at 31 degrees. The five techniques analysed were:
- Whole Body Fanning (In front of a fan with the torso, arms and legs exposed – not the head)
- Hand Immersion (Placing the hands in 17°C water to the level of the wrist)
- A phase change garment (such as a THORZT Chilly Vest)
- An air cooled garment
- A liquid cooled garment
The study found that the most effective form of cooling method after full body immersion is body fanning, followed by hand immersion. Wearing an ice vest was found to effectively cool the skin but had a “less substantial effect upon deep body temperature”.
Air cooled or liquid cooled garments were found not to be more effective than the control.
These results reinforce the need for industrial worksites to have PPE-free areas with cooling fans where workers can take advantage of evaporative cooling and hand immersion strategies.
They also strengthen the case for using Chilly Vests as a heat illness preventative measure until more effective cooling methods in PPE-free areas are possible.