It is that time of year again—the kids are out of school; summer plans are in effect and the temperature is rising. This combo normally makes for an enjoyable summer, but some are caught off guard. It doesn’t take much, just a few minutes in some cases, and when the symptoms hit it can already be too late. Heat related illness is a very real thing and should not to be taken lightly. As folks begin to hike and camp or plan a boating trip there are things you need to know and simple steps to take to ensure you and your family’s safety this summer. Stick with us as we dive into what exactly heat exhaustion is, and what you can do to prevent it!
Heat exhaustion, in short, is the body’s inability to handle heat. Unless we are dealing with a very rare state, a majority of this heat will be from the external environment. This is actually good news, because in most cases your environment can be changed to avoid the heat. Even better news, your body has inherent mechanisms with which it can rid itself of excess heat. Humans, like all mammals, have the ability to regulate their internal temperature within reason. The ability to do this depends on many factors and organ systems such as the skin and nervous system. Physical activity can raise your heat production 10-fold, thus quickly offsetting your bodies cooling capacity in hot weather or unconditioned individuals.
The hypothalamus, located in the brain, is the thermometer of the body. The body has thermo-sensors located on the surface and deep within the body. As the body warms, these sensors pick up those changes and sends a signal to the anterior hypothalamus. A series of hormones will be released, and the heart rate will increase along with cardiac output. This will increase blood flow to the surface of the body to help dissipate heat. This is one of the reasons why hydration is most important. Increasing intravascular volume creates more surface area for the heat distribution. This same relay will stimulate the exocrine glands of the skin thus sweating and cooling via evaporation. This can be a very poor form of heat transfer especially in hot weather. This mechanism is also responsible for a large amount of fluid and mineral loss which needs to be constantly replenished.
Side note: If you have ever experienced the “cold sweats” the hypothalamus is to thank. Proteins from the immune system called cytokines are release during an infection, such as in influenza. These cytokines can alter the way your body perceives the environment thus leading to strange symptoms such as feeling cold yet sweating at the same time.
Heat related illness is not defined as simply as other conditions. Symptoms can vary from person to person. It is considered more of a continuum of an illness. Heat related illness symptoms range from “heat rash”, edema (swelling) all the way to the most severe, heat stroke. If you experience one or more of the following symptoms you may be experiencing a heat related illness:
- Extremity or body rash
- Excessive sweating (even after removing yourself from the heat source)
If you believe someone is experiencing heat exhaustion or heat stroke, you should call for emergency medical assistance. Many first responders (EMT, firefighters etc.) have specific training for these situations.
Like all conditions, the impact heat has on your system is dependent on a number of factors such as your age, activity level and even what part of the country you live in. Those areas of the country that experience heat more often, such as Arizona or Florida, will have residents more “conditioned” so they may be able to handle a bit more. Now once we get into the extreme temperatures or couple in strenuous outdoor activity—even those accustomed to the heat will not be safe.
Medications and Heat Related Illness
Stimulants such as amphetamines and even caffeine can accelerate metabolism thus creating more heat. Some stimulants, such as caffeine, are diuretics which may lead to large volume loss thus creating an inefficiency in removing heat and can lead to dehydration.
The following medications can increase your risk of heat exhaustion/stroke:
- Thyroid medication
- Laxatives and diuretics
- Cardiovascular medications (Ca Channel blockers, beta blockers, etc.)
- Stimulants (diet pills, ADD/ADHD medications)
- Cough medication
- Mood disorder/sleep medications (Benzodiazepines i.e. Xanax, Ambien)
Some Tips to Avoid Heat Related Illness
Note: Temperatures of 106F require absolute immediate medical care
As the body temperature rises, cell membranes will begin to break down which leads to more destruction but also potentially increasing communicating hormones that alter sensation of environmental cues. Essential fatty acids (omega 3-6-9) and vitamin E can help to protect these cell membranes. Heat stress will also lead to oxidative stress and will require antioxidant resuscitation. Increasing your colorful fruits and veggies the day of and during activity can help mitigate this. There are also specially prepared anti-oxidant formulas. Another option, especially for those who exercise or perform manual labor in the heat is carnitine. Carnitine is a derivative amino acid. It helps produce cellular energy as well as quench oxidative damage like other antioxidants such as vitamin C.
One of the best ways to avoid heat related illness is, you guessed it, stay out of the heat. Hanging out indoors or at least in a shaded area would be best. If you have to be outdoors in the heat try and cover up with large hats, umbrellas and tents/canopies. Use a mister, if possible as this will help with the evaporative cooling without require your own body’s hydration stores.
Alcohol and Hydration
A hot summer day and a nice cold cocktail or beer—I mean that is what it is all about… but be careful. Although alcoholic beverages are a large part water, they can quickly dehydrate you. Set a drinking schedule as sometimes your thirst cues are unreliable in extreme heat. Seems silly, but setting an alarm on your phone to go off every so often as a reminder can really help. If you’re going to be engaging in strenuous activity the additions of electrolytes may help. Phosphorus, sodium and potassium are some of the most notably effected by heat related illness. Hydration acts sort like a heat soak—spreading the heat across the entire body which improves efficiency.
Cardio-pulmonary health is of importance as well. Those on beta blockers, diuretics, calcium channel blockers are at an increased risk for heat related illness. These drugs interfere with the mechanisms that raise blood pressure which can lead to a reduction in cardiac output.
The cardio-pulmonary system is one of the most efficient ways to release or rid one’s self of excess heat. Any dysfunction within this system could spell disaster for you on those hot summer days. We all know the cardiovascular system is important and exercise helps to build this part of the body. Mostly, people do this to prevent death, and yes that is important, but there are so many other advantages to having this system in tip-top shape. For one, heat dissipation. The more fluid your heart can move around the more heat you can release thus the longer you can enjoy the heat. I’d prefer exercise to be out of the sun, say in a shaded park or your local gym. If you find yourself having to workout in direct heat, please consult your physician beforehand so they can ensure your body is up to the task.
What to do if it is too late
If you see someone exhibiting the signs of heat related illness it is important to remove them from the heat source. If they cannot safely be moved, then attempt to shade or block them from the heat. Remove all articles of appropriate clothing. Now, we have to try and cool the patient rapidly and the methods will vary depending on what is available. If you have ice from your lunch cooler apply it to the core of the patient, around the chest, under the armpits and in the groin area. You need to get their temperature down quickly but not too quickly past a core temp of 100-102F. If the temperature drops rapidly past 100F it could cause a rebound effect and send the patient into hyperthermia. Dunking a patient is an ice bath is no longer recommended unless you are trained medical personnel.
If you don’t have ice then fanning the patient with a shirt or picnic blanket is a start. Be careful if you are fanning off someone in the heat with this method. Depending on your status and the ambient temperature you may be sitting right next to them in a few minutes. Do not put yourself in harm’s way as you’ll have no way to help them if you’re out for the count too. If you have friends with you, trade off every few minutes.
So, in short, the best things you can do to prevent heat related illness is to be aware of your environment and how long you may be in the heat, stay healthy by exercising and increase anti-oxidant consumption. Hydration, as we always stress, will be key to your success during the summer months. If you are to partake in alcohol consumption make sure you are staying hydrated with a non-alcoholic, low sugar beverage. Good clean water with some electrolytes is my favorite. Another important point is it takes days to recover from some heat related illnesses and you will be more susceptible to the heat during your recovery time. Take a few days out of the heat if you’ve experienced heat related illness.
Clin Exp Pharmacol Physiol. 2006 Jan-Feb;33(1-2):119-24.
Mol Genet Metab Rep. 2018 Jun; 15: 69–70.
Mil Med. 2004 Mar. 169(3):184-6.