Tortoises Need Not Apply

As the Baby Boomers begin to hit the mid-60s, they realize that their parents all died relatively young...mind you, at this point in their lives, Boomers don't consider 60 old...they figure they're just getting started. They also seem to feel that Mom and Dad succumbed early because they lacked the proper diet or exercise program or any of the host of maladie that this generation hopes to avoid.
so, they run marathons, do triathlons, bike, and hike and go to the gym to swim as well as quitting smoking, eating butter and red meat...and on and on. The malls are full of folks walking briskly every day when the weather is unreasonable. Just maybe, says Dr. Stuart Gry, they're doing it wrong.
Gray, a researcher at the University of Aberdeen's musculoskeltal research lab, opines that what everyone SHOULD be doing is high intensity exercise in order to eliminate the fat that courses through our bloodstreams, a technique that burns fat much faster than medium intensity activities like walking briskly.
Gray recommends 30 seconds of activity such as sprinting or pedaling all out on an exercise bike as typical of the kind of work that he feels is most effective. The owners of Results fitness in Santa Clarita agree, and they have been basing their workouts for 10 years on the latest research. The resulting "metabolic zone class" has shown to be very effective. Participants utilize heart rate monitors for the 45-minute classes, upping their exercise level to 85% of max then relaxing until the monitor shows a decrease to 75% of max...then they begin again. In reality, it's a simple form of interval training, though using the monitor is a more scientific way of controlling effort. After all, everyone's threshold is different so not everyone is working at the same pace at the same time. Oe might, for example, slam an exercise ball explosively downward for 30 seconds (hopefully catching it on the rebound). I would suggest that "boot camp" cl;asses might be similar, though I will never know from experience.
Having used heart rate monitors for classes of students, though, I know the device gives everyone a kind of confidence that he or she is working as hard as necessary and in a safe range.
As far as sprinting or pedaling fast? No word on how many repetitions one needs to do. I suspect I'd be done after one or two.