From the Guidelines
Cold water immersion (CWI) is beneficial for treating exertional heatstroke, with fatality rates close to zero if the body temperature is brought to less than 40.0°C within 30 min after collapse, as supported by the most recent guidelines 1. When considering the benefits and risks of CWI, it's essential to prioritize its use in life-threatening situations, such as exertional heatstroke. The 2024 American Heart Association and American Red Cross guidelines for first aid recommend immediate active cooling by using whole-body cool- to cold-water immersion for 15 minutes or until neurological symptoms resolve for adults and children with heatstroke 1. Key points to consider when using CWI for exertional heatstroke include:
- Moving the individual from the hot environment and removing excess clothing
- Limiting exertion and providing cool liquids if the person is able to swallow
- Initiating immediate active cooling using whole-body cool- to cold-water immersion
- Targeting a core temperature of 39° C (102.2° F) during active cooling
- Continuously monitoring body temperature with rectal thermometry during CWI, as recommended by the British Journal of Sports Medicine 2. It's crucial to weigh the potential benefits of CWI against the risks, particularly for individuals with pre-existing medical conditions, and to use it judiciously in real-life clinical practice.
From the Research
Benefits of Cold Water Immersion (CWI)
- CWI has been shown to increase the cooling rate by 0.03°C/min compared to passive recovery 3
- The cooling rate is more effective when the pre-immersion core temperature is ≥38.6°C, immersion water temperature is ≤10°C, ambient temperature is ≥20°C, or immersion duration is ≤10 minutes 3
- CWI is the preferred method for treating patients with exertional heat stroke, with water temperature <10°C and torso and limbs immersed 3
Comparison with Other Cooling Methods
- Cold water or ice slurry ingestion during exercise may not have a net body cooling effect in the heat due to decreased sweating efficiency 4
- However, cold ingested fluids may be beneficial for athletes with physiological disruptions to sweating, such as those with spinal cord injuries or burn injuries 4
Therapeutic Applications of CWI
- CWI has been used as a treatment for Raynaud's disease, with induced vasodilation as a home treatment showing significant increases in digital temperature 5
- CWI has also been used to diagnose and manage Raynaud syndrome, with cold challenge testing using ice water immersion with temperature recovery being highly sensitive but lacking specificity 6