Think of it as the sweet spot for exercise. The goal is to keep your rate within your optimal range, using a heart-rate monitor (treadmills often have one).
This kicks the cardiovascular system into high gear and can boost weight loss.
How to Calculate It
Mary's formula is simple: Subtract your age from 220. Multiply that number by 0.65 for the low end of the range and 0.85 for the high end -- or, use this interactive calculator. (To learn more about target heart rates, go to americanheart.com.)
Sit upright, with a grip on one shoulder and a hand on the other grip, far right. Press and release, 20 times; pulse, 20 times. Switch shoulders and repeat the exercise. Repeat for four more sets. This works biceps and triceps.
The Fitness Circle Pro, by Stott Pilates, is light enough to pack in a suitcase, so Martha can get in a workout when traveling.
This heavy ball is used in many conditioning exercises. The ones Martha uses are 9 and 12 pounds each.
The medicine ball is another good tool for core-strengthening exercises. Varying the routine keeps the body alert as it adapts to new tasks -- "muscle confusion," as Mary calls it.
Sit upright on a stability ball, with your feet rooted to the floor, your torso engaged, and your shoulders relaxed, right. Holding the medicine ball, twist twice to the left, exhaling; return to center, and inhale. Twist twice to the right. Repeat for a total of 16 to 20 reps; do two to three sets.
Light stretches give muscles a chance to lengthen after they've contracted in aerobic and strength-training exercises. Plus, taking the time to stretch clears the mind and helps Martha get ready for her busy schedule.
"Stretching is key to feeling good every day," Mary says. "I call it preventive medicine." It increases your range of motion and helps ward off injury. Don't forget to breathe.
Knees to Chest
Lie on your back. Bring your knees to your chest, keeping the lower back on the floor and your neck relaxed, right. Hold knees with your hands, or wrap your arms around them, clasping wrists or elbows.