In Summer Sense, Volume 1, we talked about the different mechanisms the body uses to lose excess heat, the environmental conditions that can cause them to not work, and the resulting heat-related illnesses that can arise.

As you’ve learned, personal factors such as age, obesity, certain medical conditions, lifestyle activities and medications can make one more prone to develop such an illness.  Let’s now look at some of these factors a little more in-depth.

Those most at risk

Younger children do not lose body heat as quickly as do adults, nor do they perspire as efficiently. The very young may not express or be aware of the need to drink or be able to get out of the heat.

Older adults also do not perspire as effectively.  Add to this a decreased thirst response, common with aging. Other medical conditions may  cause the elderly to not be fully aware of the extreme heat. Finally, many of the medications that they use (or anyone uses) may alter their body’s heat-shedding response to high temperatures.

People with chronic medical conditions are also at elevated risk as these conditions can interfere with the body’s ability to sense and react to extreme heat. Of course, the very physically active and outdoor worker are more likely to become dehydrated and at risk for heat-related illnesses.

Medications

There are numerous medications that can predispose a person to develop one of the many heat-related conditions discussed in Summer Sense Volume 1.

Let’s look at just a few of the more commonly prescribed medications and how they affect the ways our bodies respond to summertime heat.

• Beta-Blockers are commonly used to treat a number of medical conditions such as high blood pressure, heart disease, heart rhythm abnormalities and migraine headaches. These meds include propranolol, atenolol, timolol, metaprolol, nadolol and sotalol. In general terms, this class of drugs can adversely affect some of the body’s heat-losing responses, thus increasing the risk of heat-related illness.
• Diuretics (“fluid pills”) are commonly used to treat high blood pressure, certain heart problems and other medical conditions. Because they stimulate urination, their purpose is fluid loss, which can mean dehydration – not a good thing in hot weather. Examples include hydrochlorothiazide, lasix, and bumetanide, to name a few.
• Commonly used medications for “overactive bladder”, irritable bowels, diarrhea, and Parkinson’s Disease can interfere with sweating. As you know, evaporating sweat is the body’s primary means of cooling.
• Many over-the-counter cough and cold products and antihistamines for allergies can also interfere with sweating, reducing the ability to lose excess body heat efficiently.
• Alcohol and excess caffeine may cause more fluid loss than the beverages provide. Like diuretics, they are dehydrating and reduce the natural response to heat changes. Since alcohol can cause skin blood vessels to dilate, this skin-flushing can make us feel even warmer.
• Some of the commonly used antidepressants and medications used to control mood can also hinder the body’s responses to extreme heat.
• What’s more, there are some medications, such as antibiotics, that, although they do not interfere with the body’s ability to deal with extreme heat, can cause problems because they increase the skin’s sensitivity to ultraviolet rays. That can often mean a damaging sunburn or an “allergic” response to sunlight in some rare instances.
• This list highlights but a few of the many medications that can affect the body’s response to heat and so increase the risk of problems when you’re in high heat conditions.

Always consult with your doctor

If you are taking medications, it is important to be aware of their side effects, and that includes any interference with the body’s ability to sense or respond to heat. With knowledge, you can take common-sense precautions to avoid a heat-related illness. Summertime or not, never stop any medications without your healthcare provider’s agreement. Your healthcare provider or pharmacist can best advise you on any mix of medications and high heat and humidity. Remember, Truesdale Health is here to help you with your medical needs!

Coming up

Look soon for Summer Sense, Volume 3. In that post, we’ll look at ways to avoid a heat-related condition. Until next time…

Henry R. Vaillancourt MD MPH FAAFP, a Truesdale Health member, specializing in Public Health.