Tip of the Week: Six of the Worst Workout Habits

Simply going to the gym doesn't guarantee you'll have a great workout. Reading a magazine on the treadmill, skipping breakfast before aerobics class, and ditching the weight room altogether are all things people often do that diminish the value of their visit. Here are six of the worst exercise habits many personal trainers say they see every day-and the best ways to avoid wasting time at the gym:

It's Not a Library: If you're concentrating on an article in Cosmo, it probably means that you're not focusing enough on your workout. Amie Hoff, a fitness consultant with New York Sports Clubs, says that reading can be one of the worst things to do while exercising.  "If you're going to be there to work out, you have to focus on pushing your body," she says. If you do need a distraction to make it through, Hoff suggests watching television with earphones instead, since it tends to take up a little less attention.

Don't Sweat It: While getting drenched in sweat may feel like a more intense workout, shedding a few pounds of water weight is anything but healthy. "One of the things that continues to amaze me after 30 or 40 years is that people still try to sweat fat off," says Mark Occhipinti, president of the American Fitness Practitioners and Associates. "They exercise in a hot environment, thinking that they're losing fat or weight, but all they're doing is dehydrating themselves." And serious sweat can come with serious risks-the dehydration can lead to cramping and injuries. Your water intake-making sure that you have a bottle of water on hand at all times-is much more important than your water output.

Just Resist: Simply riding a stationary bike or running on a treadmill means missing out on the benefits of resistance training, which can have an even more significant impact on weight loss than a lap around the track. "You might burn 100 calories walking a mile but in the same 20 minutes with a weight machine you may burn 300-400 calories," says Occhipinti. Resistance training will also strengthen the muscles necessary for every day activity, like climbing stairs or reaching for groceries, and keep muscles in shape for old age.

Weigh In: Scared that a round of weight lifting will cause you to look like Mr. Universe? Fear no more-it's a common misconception that heavy weight lifting or resistance training will cause females to bulk up. "That doesn't happen unless you're doing growth hormones," says Occhipinti. "You're not going to become a feared freak of nature if you add some weights."

Take a Bite: Exercising on an empty stomach is like driving on an empty tank. Your body needs energy to work with. A healthy snack, such as oatmeal and a banana, can digest during the drive to the gym and provide the extra boost you need. This is especially important in the morning. Because your body has been fasting overnight, you need to give it fuel to get moving.