7. You'll build stronger bones.
As you age, bone mass goes to pot, which increases your likelihood of one day suffering a debilitating fracture. The good news: A study found that 16 weeks of resistance training increased hip bone density and elevated blood levels of osteocalcin—a marker of bone growth—by 19 percent.
8. You'll get into shape faster.
The term cardio shouldn't describe only aerobic exercise: A study found that circuit training with weights raises your heart rate 15 beats per minute higher than if you ran at 60 to 70 percent of your max heart rate. This approach strengthens muscles and provides cardiovascular benefits similar to those of aerobic exercise— so you save time without sacrificing results.
9. Your heart will be healthier.
Researchers at the University of Michigan found that people who did three total-body weight workouts a week for two months decreased their diastolic blood pressure (the bottom number) by an average of eight points. That's enough to reduce the risk of a stroke by 40 percent and the chance of a heart attack by 15 percent.
10. You'll be way more productive.
Lifting could result in a raise (or at least a pat on the back from your boss). Researchers found that workers were 15 percent more productive on days they exercised compared with days they didn't. So on days you work out, you can (theoretically) finish in eight hours what would normally take nine hours and 12 minutes. Or you'd still work for nine hours but get more done, leaving you feeling less stressed and happier with your job—another perk reported on days workers exercised.
11. You'll live longer.
University of South Carolina researchers determined that total-body strength is linked to lower risks of death from cardiovascular disease and cancer. Similarly, other scientists found that being strong during middle age is associated with "exceptional survival," defined as living to the age of 85 without developing a major disease.
12. You'll be even smarter.
Muscles strengthen your body and mind: Brazilian researchers found that six months of resistance training enhanced lifters' cognitive function. In fact, the sweat sessions resulted in better short- and long-term memory, improved verbal reasoning, and a longer attention span.
Adapted from The Women's Health Big Book of Exercises, by Adam Campbell (Rodale). Available wherever books are sold and at WHBigBookOfExercises.com.
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