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Is a good sweat necessary for a good workout?

What's the ideal room temperature for working out? Do you burn more calories if you sweat more, and in sweat pants? Smart Fitness answers your workout queries.
Image: Sweating during a workout
Don't assume that sweating is always an indicator that calorie burning is in high gear.Getty Images stock

What's the ideal room temperature for working out? Do you burn more calories if you sweat more, and in sweat pants? And have the recommendations changed for how long to rest between weight-training sessions? Smart Fitness answers your workout queries.

Have an exercise question? To e-mail us, click here. We’ll post select answers in future columns.

Q: I do an aerobic workout at a small studio. Currently, we are having a problem with room temperature. Some of the women will go and turn the a/c down to 60 degrees Fahrenheit when they start to sweat. That temperature makes some of us too cold, we prefer it stay at 70 degrees. We have resorted to wearing long pants and long-sleeved T-shirts. Is there an optimal temperature for working out and does it reduce the calories we burn if the room is too cold?

A: Actually, according to fitness experts, there is an optimal temperature for working out indoors: 68 to 72 degrees Fahrenheit. That's the range that keeps most exercisers comfortable, whether they're jogging on the treadmill, taking a step class or pumping iron.

"I find for us that 70 degrees is a good temperature for all," says Gerald Endress, an exercise physiologist and fitness director at the Duke University Diet and Fitness Center in Durham, N.C. "Those who sweat more or generate more heat can use fans that are aimed directly on their bodies."

This brings up a good point: Everyone doesn't sweat the same amount or under the same circumstances.

Some people sweat just sitting at their desks and others don't bead up until they're midway through a high-impact aerobics class. So don't assume that sweating is necessarily an accurate measure of a good workout or an indicator that calorie burning is in high gear. If it's hot and humid outside, you could break a sweat just walking out the door.

"You don't have to sweat to get a good workout, and exercising in higher temperatures and humidity can be dangerous," says Endress.

But if you're exercising indoors at around 70 degrees, there's nothing wrong with aiming for a good sweat by getting your heart rate up.

Q: While working out, is it true that wearing sweats will help you get in shape faster and give your muscles more definition than not wearing sweats? What's the ideal workout clothing?

A: The notion that wearing sweats translates into better fitness is probably a misguided take-away from all those "Rocky" movies.

There's no magic to wearing sweats. Because you may get pretty hot when you wear them to work out, you may sweat more, thus the name, we suppose. But sweating more this way doesn't mean you're losing fat any faster or somehow building more muscle. It just means you're sweating more and losing more water. That's a tactic that boxers and wrestlers use to quickly "make weight" on the day of a competition, but all it means for you is you're sweaty and need to drink more to stay properly hydrated.

So how should you dress to work out? Primarily for comfort, says Bill Sonnemaker, an Atlanta-based personal trainer and a spokesperson for the IDEA Health & Fitness Association. Don't keep clothes on that make you hot just because you think it's better to sweat more. You'll just risk getting overheated.

"People should wear layers and then remove their layers or add layers as necessary, ideally with material that breathes as well," he says.

Obviously, you'll need more layers if you're working out in the winter cold than in a spinning studio. So if you're exercising indoors, for instance, you could start out wearing sweats over top of shorts and a T-shirt, and then peel off the sweats when you get warmed up. If you're downhill skiing, you need three or four layers and a hat and gloves.

While cotton is a common fabric of fitness clothes, cotton actually traps moisture against your skin, Sonnemaker notes. It's better, especially for your first layer of clothing, to wear items made from breathable synthetic fabric, such as Coolmax and Nike Dri-FIT, that wicks away moisture.

With the moisture off of your skin, you'll feel more comfortable and will actually be able to sweat more — and therefore cool your body better.

Q: My trainer says that the guidelines now are that muscles need 72 hours rest between sessions. I thought it used to be 48. What changed? I don't feel like I'm doing enough.

A: Sounds like your trainer may be misinterpreting recently updated exercise guidelines by the American College of Sports Medicine and the American Heart Association. The guidelines recommend strength training a minimum of two days a week. So that might account for the mistaken notion that you must wait 72 hours, three days, between sessions.

But actually, the guidelines state that you can do more strength training if you like and that the added effort should confer added benefits.

Just make sure you aren't working the same muscle groups on consecutive days. That's where the standard advice still holds: Allow 48 hours between sessions. Simple translation: one day on the weights, one day off.