Risk factors for heat illness during military activities8 10
| Intrinsic risk factors | Extrinsic risk factors |
|---|---|
| Low level of physical fitness | Sleep deprivation |
| Obesity/excess body fat/high BMI* | Dehydration (insufficient water intake or excessive loss) |
| Medications (eg, antihistamines, β-blockers) | Nutritional deficit |
| Intercurrent illness (eg, gastroenteritis, cellulitis) | Inadequate heat acclimatisation |
| Chronic disease states (eg, cardiovascular disease, sickle cell trait) | Type of activity (eg, running or loaded route march) |
| Older age (>40 years old) | Type of clothing eg, body armour, impermeable and/or encapsulating uniform |
*Categorised by body composition measurement (BCM) in UK military personnel, according to associated general health risk.
BMI, body mass index.