Start by choosing any type of aerobic activity you like, such as running, cycling, stair climbing, swimming, eliptical, etc. Now, you will exercise in high intensity bursts lasting 30-90 seconds followed by 60 seconds of rest. How do you determine what "high intensity" is? Just pretend a grizzly bear is chasing you.

Start the first high intensity interval at almost 100% of your maximum effort and maintain that intensity until a) you reach 90 seconds or b) you feel as if you'd rather be Mr. Grizzly's lunch. At this point, stop and rest for exactly 60 seconds. Then, take your 15-second pulse. Immediately go into your next high intensity interval, once again pretending that you are being chased by a grizzly bear.

Continue to repeat the intervals of high intensity followed by 60-second rest periods until your 15-second pulse is clearly not recovering. Once you reach this point, your workout is finished for today. We recommend you allow for 48 hours of rest until you repeat this interval training exercise.

Grizzly Bear Intervals should be done 1-3 times per week. Also, it's recommended you use a heart monitor so you don't have to interrupt your intervals to determine your 15-second pulse.

Warning: Do not use this training method as preparation for being chased by real grizzly bears. They can run up to 35 mph. You cannot.