Should You Only Exercise During Daylight?

When fitness professional Ellen Barrett sees people out jogging at 8 p.m. in her New Haven, Conn., neighborhood, she always shakes her head.

"I just think 'Is that what you really want to do?'" she says. In Barrett's view, exercising when it's dark and cold outside is an irritant to your body and its immune system -- and a practice that could do more harm than good.

Just as farmers for centuries have gotten up with the sun to plow their fields and harvest their crops, she believes our bodies are only meant to be in vigorous motion when the sun is out.

"I think people are overriding their natural instincts, and the fitness industry is feeding into that with 24-hour gyms and 5 a.m. boot camp or spin classes," she says. "The fitness-obsessed are the ones that get the worst colds."

You might not expect this take-it-easy attitude from a fitness instructor. But Barrett, 40, who is best-known for her more than 20 exercise videos, such as Power Fusion and Grace + Gusto, believes fitness is just one part of overall health and vitality. You have to pay attention to your body and its energy level and know when to push yourself, she says. "It's a really fine line between irritation and invigoration. In spring and summer, we are meant to be more physical because of the longer and warmer days."

Indeed, she says, most exercisers should take a cue from professional ballet dancers and pile on some layers before exercise so the body and its muscles are warm and your circulation is optimal (which can also help you feel less fatigued). She's also a big fan of saunas and hot Bikram yoga classes during the cooler months.

For decades, she said, she was desensitized to her body's needs and would get up to teach class at 6 a.m. all year long. During the summer, she says, it felt great. But in the winter, she says, it left her feeling sick, achy and blue.

Now, she teaches class at 9:30 a.m. and can't remember the last time she had a cold.

While she recognizes that this schedule is not possible for everyone, she says it's better to squeeze daylight exercise in when you can -- on a lunch hour, on weekends, or during brief periods in the middle of the week -- rather than when the moon is full.

The only exception to her nighttime exercise ban? Gentle, restorative yoga, she says, is fine to do right up until you hit the sheets. Stretching and meditation are much more appropriate ways of winding down and encouraging sleep, which she says is key to maintaining a healthy weight.

"It's not a coincidence that night owls are the heaviest people," she says. "They eat late at night and skip breakfast. They are overriding their connection to nature." This "don't mess with mother nature" philosophy that Barrett spouts during class often earns her rolled eyes and giggles, she says. But it's a better way to total health than boring one-sided fitness, she says.

"Your emotional state and happiness is part of fitness," she says. "I've never seen someone who's a slave to fitness who's happy. You have to be able to go with the flow a little bit."

To that end, Barrett sets up her workouts so there's a lot of stretching and "big breathing" to coax the body into motion and ease tension before moving on to more strenuous work.

Don't get her wrong: She's not telling you to hibernate during the winter or abandon your marathon training. She just thinks people worry a bit too much about burning calories and how they look in their skinny jeans.

"What's really attractive is the person who has a lot of life experience and isn't just one-dimensional," Barrett says. "Make fitness part of your life, but don't make it your life."

SecondAct contributor Melinda Fulmer writes regularly about issues of health and wealth for publications such as the Los Angeles Times and web portal MSN.

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