Image: People run on treadmills at a New York Sports Club January 2, 2003 in Brooklyn, New York.
Spencer Platt  /  Getty Images file
More time on the treadmill isn't necessarily better, experts say.
By MSNBC contributor
updated 12/27/2007 11:25:33 AM ET 2007-12-27T16:25:33

Can you get too much cardio? Is there an ideal amount of exercise for losing weight? And are you ever too old to shape up? 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 exercise on a regular basis, at least five to six days a week, consisting of mostly cardio with weight-lifting on three of those days. However, I have heard that too much cardio can be bad for you. Is this true? If so, how much time should be spent on cardio?

A:
"You'd have to do an awful lot to do too much, to hurt your heart," says Dr. William Roberts, a past-president of the American College of Sports Medicine. "Most people aren't exercising enough to worry about this."

New exercise guidelines released earlier this year by the ACSM and the American Heart Association encourage people to get at least 30 minutes of moderate-intensity cardiovascular exercise, such as brisk walking, five days a week or at least 20 minutes of more intense cardio, such as jogging, three times a week. The guidelines also call for strength-training on at least two days.

You don’t say how long you’re exercising or how hard, but if you’re getting these minimum amounts of cardio, your fitness regimen seems to fit in with the guidelines.

The recommendations are based on studies showing how much exercise is needed to improve and maintain health. Exercising more than these minimum amounts may confer added health benefit but just how much is unclear.

“The biggest bang for your buck is at 30 minutes,” says fitness researcher Dr. I-Min Lee, an author of the guidelines and an associate professor of medicine at Harvard Medical School. “A little [exercise] is good, more is better — up to a point,” she says.

It’s not known what that point is for everyone, but if you’re getting injured, feeling overly fatigued or if you're working out so much it's interfering with your life, you’ve reached that point and should cut back, says Roberts, who is a professor of sports medicine at the University of Minnesota Medical School.

Lee notes that sudden cardiac death also is a risk factor from pushing yourself too hard, but it’s rare and usually strikes people who are out of shape and overdo it — such as sedentary people who jump off the couch and go shovel snow, or those who run marathons and have heart risk factors and aren’t properly conditioned.

Q: I have been told by a trainer that cardio performed over an hour is counterproductive to my weight-loss goals. But I prefer to cycle for a full two hours because I love it. I've lost 30 pounds with my cycling program so far. Any reason to cut back?

A: No. The new exercise guidelines say that people who want to lose weight should do more than the minimum amounts, upwards of an hour or more of exercise on most days.

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There’s no reason for people to cut back on their exercise program as long as they’re happy and healthy, notes Lee.

Plus, your weight-loss plan is working! You’re losing weight and you enjoy the activity. Hard to argue with that. 

Q: I just turned 49 and I weigh 230 pounds. My whole adult life I have lost weight and regained it in an endless cycle. I’m wondering whether I’m too old to take the weight off now and get in shape. Someone at my gym told me that at my age, my body will not get back in shape. All I could do was walk out of the gym upset and crying. Help! Is this true?

A: If that someone was a trainer, you should march back in that gym and question their credentials. No qualified fitness expert would ever tell you such nonsense.

Trying to look like Gisele Bundchen? That's another story. Genetics and age have a lot to do with just how buff and beautiful we can be.

But you're never too old to exercise or lose weight.

© 2013 msnbc.com

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