5 Supplements for Heat Intolerance

When your body is dehydrated, it lacks water and essential salts — called electrolytes. These electrolytes are what allow your body to sweat. If you can't sweat, you can't cool down. So, while electrolytes won't specifically reduce heat intolerance, they can address its side effects.

The easiest way to reintroduce electrolytes into your system is to drink a beverage formulated with them. Many sports drinks like Gatorade contain electrolytes, but they also tend to be high in sugar, which can be a problem if you're a diabetic or on a weight-loss plan. However, there are those — particularly ones formulated for children — with less sugar, so opt for those instead.

In a study published in the journal Clinical Science in 2015, researchers from Penn State University found that when older adults and the elderly were exposed to heat, they were less able to increase blood flow than younger adults. This made the older study participants more at risk for many things, including heat stroke.

The researchers determined this was because as we age, our blood vessels produce less nitric oxide. They then hypothesized that folic acid and its metabolite, 5-methyltetrahydrofolate (5-MTHF), could improve the elderly group's vessel function. And they were right. When the older study participants took folic acid supplements, their cutaneous microvascular function improved, and in turn, also helped maintain their body temperature even when they were subjected to hotter temperatures.

Magnesium is the fourth most abundant mineral in your body. It's involved in more than 600 reactions, including energy metabolism and protein synthesis. But between 56 and 68 percent of Americans don't enough magnesium in their diets. A study published in the Clinical Physiology and Pharmacology found that magnesium plays a definite role in thermoregulation. While the study was small, it was concise and included a group of men who underwent a thorough acclimatization process in a heat chamber while they walked on a treadmill for 10 days. They received magnesium on days one, five and 10 before and after the heat exposure.

The researchers concluded that "unless there is an adequate supply of magnesium to compensate for increased demand, repeated heat exposures may over time lead to severe magnesium deficiency and a failure of thermoregulation, e.g., heat stroke, exertional heat stroke, or other forms of malignant hyperthermia."

So what is the Recommended Dietary Allowance (RDA) for magnesium? For men 19 to 51-plus years it's 400-420 mg; for women it's 310-320 mg.

We already mentioned electrolytes and potassium is one example. But there's a specific group of people that potassium is ideal for and that's anyone taking diuretics. That's because this group is already at risk for lower potassium levels, and that means they're also at an increased risk of heat stroke, cardiac arrhythmia and even death. But the good news is a 2019 study published in BMJ Open by researchers at the Perelman School of Medicine at the University of Pennsylvania found that prescription potassium supplements can reduce these risk factors by nearly 10 percent.

"We already know that hot outdoor temperatures are associated with increased risk of heat stroke, dehydration, heart disease, respiratory diseases and higher risk of death overall, but people who take furosemide [a prescription diuretic] and have insufficient intake of potassium are at increased risk," senior author Sean Hennessy, Ph.D. said in a press statement. "As outside temperatures increase, the apparent survival benefit of potassium also increases."

Up until now, we've discussed mostly supplements for heat stroke and heat intolerance. But what about hot flashes? They're a common symptom of menopause and can feel like a flare of heat coming out of nowhere. They're uncomfortable and treating them is notoriously difficult.

Fortunately, there are supplements that can help. One of those is vitamin E. There have been several studies on vitamin E and hot flashes, but a 2020 study published in Complementary Therapies in Medicine confirmed what many others have. It works. In this triple-blind, randomized controlled clinical trial, 93 postmenopausal women were assigned into three groups (two intervention groups and one control group). The first group received the supplement curcumin; the second group was given oral tablets of vitamin E; and the third group (control) received a placebo twice a day for eight weeks. The participants filled out a hot flash checklist one week before the intervention, and four weeks and eight weeks after the intervention.

What the researchers found was both vitamin E and curcumin significantly reduced hot flashes in postmenopausal women.