Hot temperatures are a known factor for every Marine and Sailor when it comes to outdoor physical training on most Marine Corps installations. With temperatures rising, so does the risk of becoming a heat casualty.

According to the Center for Disease Control and Prevention (CDC) website, a heat-related illness is caused by the body not being able to cool itself properly.

“You are pushing yourself where your core body temperature increases to where your body has a physical reaction to the rise,” said Petty Officer 2nd Class, Allen Miranda, a hospital corpsman with 2D Marine Regiment. “It does not have to take place during hot months, it can take place in cold training where you have too much gear on you.”

Watching for signs of a heat injury can help Marines and Sailors determine the extent of an injury before it can get worse. Some signs include altered mental status, loss of consciousness and determination of core temperature.

“We definitely see a lot of heat cramps and heat exhaustion,” Miranda said. “Heat stroke is rare because normally a person will get to heat exhaustion first. Once a corpsman or a Marine sees those signs, it is usually dealt with before it gets to become a heat stroke.”

Miranda added Marines and Sailors, need to properly take care of their bodies to prevent heat injuries. Eating properly, getting the right amount of sleep and staying hydrated are some examples.

Another guide to follow is the Flag Warning System that is set from the Wet Bulb, Globe Temperature Index (WBGT) by the Automated Heat Stress System (AHSS). The AHSS sets a standard of color coded flags that assists setting proper guidelines for outdoor working and physical exercise conditions.

“[Flag conditions are] based off of a wet bulb reading,” Miranda said. “It is a device that measures ambient temperature, wind speed, humidity and a couple other factors. This all comes together to give an accurate temperature around you.”

There are five colors for the different flag conditions. Blue, green, yellow, red and black with blue being the least severe and black being the most severe flag condition. Each flag condition provides a recommended guideline for how long you should exert yourself and for what type of training.

“If you are training with specific amounts of weight, it will change how hot it technically is with that weight on,” Miranda said. “It can be red flag or yellow flag, but if you put a Kevlar on with a 70 pound flak, for you it is no longer a red or yellow flag.”

Whether you are physically training by yourself or with your unit, the AHSS should always be monitored. Knowing the signs and ways to prevent heat injuries keeps Marines and Sailors fighting in every clime and place.

For more information about heat injuries, visit or For more information about the Flag Warning System, visit or