Don't settle for an ounce of prevention; weights may offer it by the pound. A University of Florida study found that people who performed three resistance training workouts three times a week for 6 months experienced significantly less oxidative cell damage than nonlifters. That's important since damaged cells can lead to cancer and other diseases. And in a study published in Medicine and Science in Sports and Exercise scientists discovered that resistance training speeds the rate at which food is moved through your large intestine by up to 56 percent, an effect that's thought to reduce the risk for colon cancer.
10. Your Diet Will Improve
Lifting weights provides a double dose of fat-loss fuel: On top of burning calories, exercise helps your brain stick to a diet. University of Pittsburgh researchers studied 169 overweight adults for 2 years and found that the participants who didn't follow a 3-hour-a-week training plan ate more than their allotted 1,500 calories per day. The reverse was also true—sneaking snacks sabotaged their workouts. The study authors say that it's likely both actions act as a reminder to stay on track, reinforcing your weight-loss goal and drive.
11. You'll Handle Stress Better
Break a sweat in the weight room and you'll stay cool under pressure. Texas A&M University scientists determined that the fittest people exhibited lower levels of stress hormones than those who were the least fit. And in another study, researchers at the Medical College of Georgia found that the blood pressure levels of people with the most muscle returned to normal the fastest after a stressful situation, compared to those who had the least muscle.
12. You'll Shrug Off Jet Lag
Next time you travel overseas, hit the hotel gym before you unpack. When researchers at Northwestern University and the University of California at San Francisco studied muscle biopsies from people who had performed resistance exercise, they discovered changes in the proteins that regulate circadian rhythms. The researchers' conclusion? Strength training helps your body adjust faster to a change in time zones or work shifts.
13. You'll Be Happier
Yoga isn't the only exercise that's soothing. Researchers at the University of Alabama-Birmingham discovered that people who performed three weight workouts a week for six months significantly improved their scores on measures of anger and overall mood.
14. You'll Sleep Better
Lifting hard helps you rest easier. Australian researchers observed that patients who performed three total-body weight workouts a week for 8 weeks experienced a 23 percent improvement in sleep quality. In fact, the study participants were able to fall asleep faster and slept longer than before they started lifting weights.
15. You'll Get in Shape Faster
The term "cardio" shouldn't just describe aerobic exercise. A study at the University of Hawaii found that circuit training with weights raises your heart rate 15 beats per minute higher than running at about 60 percent to 70 percent of your maximum heart rate. According to the researchers, this approach not only strengthens your muscles, it provides cardiovascular benefits similar to those of aerobic exercise. So you save time without sacrificing results.