| What it is | Abnormally high body temperature |
| Opposite of | Hypothermia |
| Spectrum | Cramps → exhaustion → heat stroke |
| Prevent with | Hydration, pacing, shade, cooling |
Hyperthermia is an abnormally elevated body temperature caused by the body absorbing or producing more heat than it can shed, the opposite of hypothermia. It spans a spectrum of heat illness from heat cramps and heat exhaustion to life-threatening heat stroke, and is prevented by hydration, pacing, shade, and cooling in hot conditions.
This is general educational information, not medical advice. In an emergency, seek professional medical help.
The spectrum
It runs from heat exhaustion to emergency heat stroke, worsened by dehydration. Reduce risk with sun protection.
Frequently asked questions
What is hyperthermia?
Hyperthermia is the condition of having an abnormally high body temperature because the body gains heat faster than it can release it — through heavy exertion, hot environments, dehydration, or limited cooling. It's the umbrella term for heat illness, the opposite of hypothermia (dangerous cold).
What are the types of heat illness?
Heat illness ranges in severity: heat cramps (painful muscle spasms), heat exhaustion (heavy sweating, weakness, nausea, dizziness with a still-functioning cooling system), and heat stroke (a medical emergency where the body's temperature regulation fails, with very high temperature and altered mental state).
How do you prevent hyperthermia?
Hydrate well (with electrolytes on long, hot efforts), pace yourself and rest in shade during peak heat, wear light breathable clothing and sun protection, acclimatize gradually to heat, and recognize early symptoms in yourself and partners so you can stop and cool down before it escalates.
Sources
- Heat-related illness — CDC
- Heat illness — Wilderness Medical Society