But the scientific data shows that, in addition to those calories you burn from general physical activities, you also need about 60 minutes a week of stamina training-that is, a cardiovascular activity that elevates your heart rate to 70 percent or more of your age-adjusted maximum (220 minus your age) for an extended period of time.
Ultimately, the stamina training necessary to obtain optimum health (more is needed for getting in great shape but not needed for health) comes in the form of only three 20-minute workouts per week at this heart rate.
The funny thing is that once you go over 60 or so minutes, there's no more benefit to your body from a longevity standpoint. And by burning more than 6,500 calories a week, you actually decrease your longevity because of the wear and tear your body endures going through the rigors of additional exercise. For example, a 55-year-old man who burns 6,500 calories a week has the body of a 47-year-old man, while a 55-year-old man who burns more than that only has the body of a 52-year-old man. Only three 20-minute workouts might not be the best regimen for someone who needs to lose 90 pounds or wants to win the Boston Marathon, but it is the best choice for living younger and living longer over the long run.
That 20-minute workout is defined as 20 minutes of sustained activity that leads to being slightly out of breath, or enough to break a sweat during that time. We know that you have responsibilities to jobs, kids, and the 3-foot-high weeds in the backyard, but it's good to be selfish when it comes to taking time for exercise-especially when you realize you'll be in better shape to take care of your kids or parents. If you're in a time crunch, I suggest setting the alarm clock back 30 minutes. The earlier you can exercise, the fewer distractions you'll have to deter you from doing it later in the day.
Find out more about this book:YOU: The Owner's Manual, Updated and Expanded Edition: An Insider's Guide to the Body that Will Make You Healthier and Younger