A warm and humid day can make just about anyone uncomfortable but did you know that relatively mild conditions can be taxing for people with heart issues?

That's right. It does not take extreme heat to affect the heart. Experts say when it reaches 70 degrees with 70% humidity, people with tender hearts should take notice.

Here's why: When you feel warm, your body tries to keep cool by sweating and sending more blood to the tiny vessels just beneath your skin.

As the volume of blood drops elsewhere, the heart has to work harder.

Some medicines further complicate the picture, such as diuretics, that's "water pills." People taking these have a greater risk of dehydration in hot weather, which makes your heart pump harder.

So how do you stay heart-safe when the temperatures rise?

Watch the heat index, which combines temperature and relative humidity. If it's high, be especially careful outdoors.

Better yet, stay inside, where there's a fan or air conditioning. Kick back and keep a cool beverage without alcohol or caffeine at hand. Your heart will appreciate the breather.