Heat alerts, smog alerts. Welcome to summer in the 21st century and more excuses to sit around and not get exercise.

"It's just too damn hot" is a slightly better excuse for not getting out and maintaining your fitness than "I've got to find out who gets voted off tonight."

Well, most of the folks who study risks and benefits of exercise say the benefits of getting your butt off the couch on a hot day outweigh the risks, as long as you're a healthy and somewhat normal person.

If you're not prepared, there are some pretty nasty things that exercising in the heat can do to you.

Still, there are things you can do to cope. There's the easy stuff, like limiting your outdoor exercise time to those parts of the day when heat and smog levels are lowest — before seven in the morning and after eight at night.

And then there's cooling off. Before you exercise. Several studies have shown that cooling yourself before exercise will improve your performance in hot weather.

One study found that for endurance performance — anything over half an hour — you can do much better by cooling down your body before exercising than by doing a traditional warm-up. Participants in the study wore a cooling vest for 20 minutes before getting on a treadmill and running at progressively faster paces until they were exhausted. People who wore the vests had measurably lower heart rates and body temperatures than those who warmed up.

And it's not just for runners. A study that followed squash players came to similar conclusions.

Despite the evidence that pre-cooling works, you'd be hard-pressed to find anyone who will recommend that you cool off before working out in the heat. Which is too bad, because you're doing your body a lot of good by slogging through the heat, even if it feels like you're barely able to move your feet.

If you want to make it slightly more bearable, you could soak in a cold tub before heading out.

I like to stick close to that big lake that keeps the U.S. a comfortable distance from Toronto — and hope for a bit of a breeze. Makes lying in the hammock and sipping on a cool beverage a little later that much more enjoyable.