Jumping on the treadmill or cross trainer for 30 minutes can blow off tension by increasing levels of "soothing" brain chemicals like serotonin, dopamine, and norepinephrine. What's fascinating, though, is that exercise may actually work on a cellular level to reverse stress's toll on our aging process, according to a 2010 study from the University of California—San Francisco. The researchers found that stressed-out women who exercised vigorously for an average of 45 minutes over a three-day period had cells that showed fewer signs of aging compared to women who were stressed and inactive. Working out also helps keep us from ruminating "by altering blood flow to those areas in the brain involved in triggering us to relive these stressful thoughts again and again," says study coauthor Elissa Epel, an associate professor of psychiatry at UCSF.
That’s bad news, but emerging evidence shows that there are plenty of compelling reasons to start moving at any age and even if you’re ill or pregnant. Indeed, scientists are learning that exercise is, actually, medicine. “There is no pill that comes close to what exercise can do,” says Claude Bouchard, director of the human genomics laboratory at Pennington Biomedical Research Center in Louisiana. “And if there was one, it would be extremely expensive.”
Most people find they can't do a full minute of press-ups without their muscles giving in to begin with. If your muscles fail on you, don't think of it as a point of no return. Instead, take a moment to rest and continue with the exercise for as long as possible, just as you did the abdominal plank. Bit by bit, you'll find your press-up stamina improving.