When the temperatures climb above 90 degrees (or even 80), you're moving into a different world for outdoor workouts and you have to more carefully monitor foods, fluids and energy so you keep vital minerals in balance and don't overtax your circulatory system.

When the temperatures climb above 90 degrees (or even 80), you're moving into a different world for outdoor workouts and you have to more carefully monitor foods, fluids and energy so you keep vital minerals in balance and don't overtax your circulatory system.

"Don't work out in extreme heat," says Andy Baxter of Baxter Fitness Solutions in Medford and Ashland. "Your body is diverting blood into the skin, for cooling, and away from blood supply for muscles. As a result, you get a false heart rate, which doesn't accurately indicate your workload."

The signs that you might not be getting enough blood to the interior of your body are irregular breath, inability to talk comfortably while you work out, blood rushing to the head, and red skin tone, says 100-mile runner Hal Koerner of Ashland

"Once that feverish feeling reaches your head, we're talking serious dehydration or even heat stroke," says Koerner.

In short, get thee to an air-conditioned gym during the hot weather or get out of bed early and do it outside before that ball of fire gets too high in the sky. Late in the evening is good, too, he says.

And in any case, Baxter notes, don't work out in the direct sun or without plenty of electrolyte-rich drinks containing the "big three" — calcium, sodium and potassium.

Running shops, like Koerner's Rogue Valley Runners in Ashland, offer plenty of equipment — packs, hand-held water bottles, camel-back water packs that you suck on through a flexible straw — as well as energy bars, salt tablets with extra sodium and potassium and Gu's, a gel you squeeze in your mouth, containing complex and simple sugars, electrolytes and amino acids.

In intense heat, the body is sweating and depleting resources fast and plain old water just isn't good enough, says personal trainer Carol Lee Rogers of Ashland. So you need to check out electrolyte drinks like ReCharge, making sure you get the ones without sugar and corn syrups.

"But the main thing is, if it's hot, get up early or go out late so you're not in that excruciating heat. If you can't avoid the heat, work out for a shorter time."

As for your diet, you can stick mostly with the same foods, these trainers say, especially if you're avoiding the hot hours. However, they do recommend an uptick in hi-fiber foods, which have a lower glycemic index (they burn slower) and fruit consumption, especially bananas, as they contain both water and the fast-burning sugars you need for a good workout.

Remember, says Baxter, you're supposed to feel energized after a workout, not droopy, so if you feel "beat up," the heat is getting to you and you need to cut back on duration, location (go inside) or dehydration.

John Darling is a freelance writer living in Ashland. E-mail him at jdarling@jeffnet.org.