I ran the idea by a client who is a health & wellness coach, and she verified that research shows this type of aerobic workout produces good weight-loss and endurance results. She said that it has allowed her to cut her workouts to 30 minutes in length; she said, "It's totally transformed the way I work out."
This technique falls under the category of High Intensity Training or HIT. This past month, I've been experimenting with HIT intervals, and I'll give you some of my impressions. At the end of this post, I'll share my exact method.
Here are my overall impressions.
On the positive side, it indeed allows you to get in and out of the gym very quickly. I give myself 20 minutes to complete three sets of HIT intervals, and I'm exhausted and ready to shower at the end of that time. Also, I have noticed a significant, quicker improvement in my endurance. (This method reminds me of the techniques our high school basketball coaches used in the first few weeks of the season to get us into shape quickly.) I haven't been able to tell whether it's better or worse for weight loss, though my waist line continues to go down slowly.
On the negative side, I find that I enjoy my workouts far less. The one-hour routine I do on the elliptical feels so much more peaceful and fun; when I do that exercise, I moderately exert myself on the tough intervals (instead of "going as hard as I can"), and I meditate during them, as well. In addition to making my workouts very enjoyable, I'm seeing some remarkable mindfulness results outside of the gym as a result of blending aerobics with meditation.
Also, I find that I'm groggier after doing the HIT intervals than I am when I do my regular routine. (They take more out of me.) There is the fact that, in due time, getting into better shape will reduce the groggy after effect. However, I work at a job in which I really need to be mentally sharp.
So,there's a tension between the benefit of faster results and getting out of the gym quicker, versus enjoying the workouts themselves and being more mentally alert as you get into shape. To address this tension, I've decided on a compromise: I'll do my regular routine during the work week, and I'll add one HIT interval session on the weekend. That way, I can stay alert during the work week, and I can get in and out of the gym faster during a weekend session, allowing more time with my family.
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Here are specifics about how I do my HIT intervals.
I use an elliptical machine that allows for adjusting the incline and resistance. I set the machine so that I can move fairly easily; for me, that would be an incline of 6 and a resistance of 8. Finally, I set the timer for 20 minutes.
For my first HIT interval set, I go as hard and fast as I can for 20 seconds, rest for 10 seconds, and repeat 5 times. Then, I move at a restful pace for a few minutes until I'm no longer winded. For my second set, I do 15 seconds as hard and fast as I can, rest for 10 seconds, repeat 5 times, and then rest. For my third set, I do 10 seconds as hard and fast as I can, rest for 10 seconds, repeat 5 times, and then move slowly and restfully for whatever time remains on the machine. I'm done in 20 minutes.
The other day, I attempted 4 sets instead of 3, and I felt a dizziness and slight nausea that didn't go away until I got into the locker room and took a cool shower. I'd pushed myself too hard, too soon. Later that day, I took a 2-hour nap. (In the interest of full disclosure, I'm 53 years old.)
Once I dialed it back to 3 sets, I was able to do these HIT intervals without the severe after effects. Listen to your body, and adjust as you go. Of course, hiring a personal trainer can help you to structure your workouts so that they don't get too hard too quickly.