Heat stress is the broad category of conditions related to being in a heat-filled environment.

The Center for Disease Control/National Institute for Occupational Safety and Health (NIOSH) lists five different conditions that fall under the category of Heat Stress:

1. Heat stroke occurs when the body reaches 104 degrees Fahrenheit or higher, and can be brought on by heat or activities that raise the body's temperature.

2. Heat exhaustion is the body's reaction to loss of water and salt.

3. Heat syncope is fainting or dizziness associated with long periods of standing, or rising quickly from a seated position.

4. Heat cramps are muscle spasms that typically occur during physical activity in a hot environment.

5. Heat rash is skin irritation due to excessive sweating in hot weather.

While the conditions have many overlapping symptoms, and are all somewhat related, each may be different in how it manifests in individuals. Check the NIOSH piece for specific symptoms of each and tips on preventing injuries from these conditions.

Heat stress is most likely to be a problem for those whose jobs require working in hot environments including bakers, firefighters, and boiler room workers. And while those occupations may appear to be obvious culprits, others in the population are also at risk:

Children with special needs may not recognize their need for more fluids, or may not be physically able to get a drink for themselves.

Infants and very young children are especially prone to heat stroke and heat exhaustion. Watch for signs such as increased thirst, decreased urination, shortness of breath, dizziness, and difficulty to rouse.

Weather.com's warning about heat-related illnesses points out that dehydration is a "common human response" in regions where humidity is low. In areas where the climate delivers high summer temperatures, and low humidity, people don't always recognize their need for fluids until their body has become dehydrated, whereas in areas of high humidity, the heat index (how hot it really feels) is higher, and it seems hotter than it actually is.

Tips for avoiding heat stress illnesses:

  • Limit outdoor play.
  • Take rest breaks in the shade, or indoors.
  • Watch children carefully for signs of dehydration.
  • Do not travel — even short distances — without water.
  • Do not leave children in a hot car, and make sure parked cars are locked. Deaths from children in hot cars continue to be a tragic problem. Not all of the deaths resulted from them being left inside, but occurred after kids climbed in and then accidentally locked themselves in the car.

There are lots of good internet resources from both medical sites and weather sites about heat, and heat-related conditions: