I didn’t put two and two together when I was experiencing the symptoms of heat exhaustion during a high exertion hike last week, but after a friend pointed it out to me, I realized that I’d had a close call.
While I’d taken precautions against the sunlight and heat such as drinking plenty of water, monitoring my urine color, eating salty foods, wearing a hat, and loose-fitting, well-ventilated, and lightly colored clothing, the location I’d been hiking in had put me at high risk.
For example, I’d hiked 8 miles of black-top and a cinder covered rail trail during the middle of a hot sunny and humid day, followed by a 3000 foot climb up a steep mountain with a 30 pound backpack. The following day, I hiked another very strenuous 6 miles above treeline in full sunlight, where I could feel the heat reflecting off the boulder fields I had to traverse.
I’ve hiked the same and similar routes previously with no ill effects, so I really didn’t think I was at risk. I was drinking plenty of water, eating salty food during the day and felt that I was staying ahead of the salt depletion and dehydration curve.
Still, I experienced a few symptoms that I should have paid more attention to such as gagging on food during meals, loss of appetite, and mild stomach cramping. At the time, I wrote these off to a case of nerves because I was hiking over a highly exposed section of trail where I’d had a close call the previous summer in a thunderstorm, with lightning and hail. It never crossed my mind that I was suffering from a heat-related illness.
Heat Related Illnesses and Hiking
There are three levels of heat related illness that hikers should be concerned about in hot weather: heat cramping, heat exhaustion, and heat stroke.
- Heat cramping occurs when you become dehydrated and experience leg or abdomen cramps and sweat more heavily than normal.
- Heat exhaustion can occur after you’ve been exposed to high temperatures for several days. Symptoms include heavy sweating, weakness, dizziness, dark-colored urine, fainting, fatigue, confusion, muscle cramps, nausea, and weak pulse.
- Heat stroke (sunstroke), the most dangerous heat related illness can be fatal and requires immediate hospital treatment. Symptoms include throbbing headache, confusion, nausea, dizziness, shallow breathing and unconsciousness.
Given the overlap in the symptomatology, it can be difficult to differentiate one level from the next. The difference between them is a matter of degree, particularly in your body’s ability to self regulate its temperature and how fast you can recover. For example, you can usually recover quickly from heat cramping by properly rehydrating, but heat exhaustion may take several days or even weeks to get over.
Given my symptoms, I figured my condition fell somewhere between heat cramping and heat exhaustion, but was getting progressively worse as I continued hiking without any extensive rest breaks or a day off.
Once I got below treeline and off the baking rocks of the Northern Presidential mountains, I sought out a shady camping spot in the forest near a cool stream. There I washed three days worth of sweat off my body (LNT style), more to get clean than to cool off my body, even though that is a recommended treatment for heat exhaustion. After bathing, I continued to experience nausea while trying to get some dinner down and then had to struggle to stay awake until nightfall.
Treatment for Heat Exhaustion
The primary treatment for heat exhaustion is to rest in a shady spot or, better, an air-conditioned room, and to drink cool water. You can lower core body temperature by immersing yourself in cold water or spraying yourself with cold water and fanning. Water is usually enough to reverse dehydration, but electrolyte-enhanced sports drink can also be helpful for recovery. If you don’t feel better within an hour, it’s recommended that you seek medical treatment which can include rehydration via intravenous fluid and more aggressive cooling using ice blankets and cold water immersion.
Preventing Heat Exhaustion
- The best way to prevent heat exhaustion is to prehydrate before a hike and to drink plenty of fluids in hot weather. Rather than drinking a lot of water at once, it’s best to drink a few sips very frequently. During periods of intense exertion, such as hiking up a steep trail in hot and humid weather, your body can lose 1 quart of perspiration per hour.
- Hike early in the day and seek routes that are well shaded from direct sunlight between the hours of 10 am and 4 pm. It will still be hot in the late afternoon, but less hot than during mid-day.
- Wear loosefitting, lightweight, and lightly colored clothing that doesn’t hold in the heat and helps your body cool properly by sweat evaporation.
- Eat salty foods such as chips or nuts to replace electrolytes than be lost by sweating. Electrolyte drinks can also be helpful.
- Wear a wide brimmed hat or carry a trekking umbrella to help avoid sunburn. Sunburn make it harder for your body to cool itself. Cover up with light, loose clothing or wear sunscreen.
- Scale back the distance and elevation gain you tackle on hot days. Take longer breaks and drink plenty of fluids while resting.
- Monitor your urine. If you’re properly hydrated you should be peeing frequently and your urine should be clear. If your urine is a darker yellow, you need to drink more.