As they say, it’s not the heat, it’s the humidity. This is especially true for seniors with health conditions such as heart disease, lung disease, kidney disease, and high blood pressure (also known as hypertension).
In general, seniors are greater risk for heat-related conditions, such as dehydration, heat stress, and sunstroke. This is due to a number of factors, including their bodies’ diminishing ability to regulate their temperature, as well as the side effects of some of the medications they may take.
However, even when the temperature is relatively mild — in the low 70s — if the humidity is greater than 70%, those with the conditions listed above can be disproportionately subject to dehydration, according to the US Department of Veteran Affairs.
Why is this so? One of the ways in which the body cools itself is through sweating. However, that only works if the sweat can evaporate. And if it’s humid, sweat doesn’t evaporate efficiently, and body temperature continues to rise.
Moreover, sweating decreases blood volume. As a result, the heart needs to work much harder to pump that smaller volume of blood throughout the body.
The takeaway: seniors should take extra care on humid days, even if the temperature is comfortable. See our post, 3 Tips for Avoiding Senior Dehydration, for information on how to stay hydrated through the dog days of summer.