Sam’s wife, Mary, is 64 and has been exercising regularly for the past 20 years. She likes to swim, walk and use the stationary bicycle in the fitness center. She has heard and read a lot about the advantages of exercising more vigorously, and her doctor has cleared her to progress, with caution to choose low-impact exercises that don’t aggravate her osteoarthritis. With the guidance of a professional trainer, Mary begins incorporating interval training into her regimen.

Interval training is a method of training that combines short, high-intensity bursts of speed with short recovery phases that are repeated throughout a single workout. On the treadmill and the stationary bicycle, as well as in the pool, Mary did three minutes at her regular pace, and added one minute at a faster pace – at the regular, moderate pace, she felt like a 4-6 on the scale, and at the faster, vigorous pace, she felt like a 7-8. After several months she was able to maintain that vigorous pace for 15 minutes a day, five days per week, allowing her to do 75 minutes of vigorous activity per week. She didn’t always want to be so vigorous, so she alternated weeks of moderate and vigorous activity.  Some weeks she did 150 minutes of mdoerate activity, and others consisted of 75 minutes of vigorous activity. The variety of exercises kept her from overworking certain muscles and joints, and her arthritis was well controlled.

Sam decided after six months that he also wanted to step it up a bit. He liked a moderate pace, so he slowly added more minutes to each week, and after another six months was up to 300 minutes per week!