7.5 Minutes of Exercise?

Jade Teta ND, CSCS

I have come to understand not everyone loves exercise the same way I do. Many people would much rather spend their free time eating or watching their favorite TV show. Unfortunately the trade off for their health is catastrophic. A new study in the journal BMC Endocrine Disorders published online January 28th 2009 shows time may not be as much an issue as most people think. For those of you who are familiar with Metabolic Effect and the short-duration high-intensity workout program we use, this may not be news to you. But for those of you who are not, you may have just found your excuse to get off the couch for a only a few minutes every week.

In this study 16 men underwent 6 sessions of sprint interval training over a period of fourteen days. There were 1 or 2 days of no activity between each exercise bout. Each exercise session involved 4-6 all out sprints followed by 4 minutes of rest. The interesting thing about this protocol is that the rest was actual rest. During the rest, participants either peddled in a slow motion relaxing pattern or literally sat doing nothing until the next sprint. The total time of the workout took between 17-26 minutes, but only 2-3 minutes of that time was actually spent doing exercise. The remainder of the time was rest. The researchers measured three strong predictors of type 2 diabetes including glucose, insulin and fat response to an oral glucose tolerance test. This is a test where 75 grams of sugar is given (about the amount of sugar in 2 cans of Cocoa Cola). Then the blood is monitored to see how fast sugar appears in the blood, how much of the fat storing hormone insulin is produced in response, and how much fat your body makes from it. If you are like most people this test is not a very pleasant experience for your body. Although you may not be aware of it this kind of sugar load drastically impairs metabolic function. Which is pretty scary considering most people easily eat this much sugar in a standard American breakfast.

The amazing thing is that at the end of the 14 day period only 7.5 minutes of exercise had been done, yet there was statistically significant improvement in metabolic function in response to the sugar load. What may be shocking to many people is that standard aerobic exercise prescriptions like jogging and walking do not have the same effect (1-7). Walking has not been shown to improve any of the three parameters measured and jogging/running has only been shown to impact insulin levels but not glucose or fat responses to a sugar load (1-7).

The good news for those of you who don’t care for exercise is that four 30s sprints done in between commercial breaks while watching your favorite TV show just may allow you to have your cake and eat it too. The researchers noted that the total caloric expenditure of the exercise protocol per week amounts to 225 calories. This is in stark contrast to the 2,000 calories usually used in a standard aerobic exercise protocol. This led the researchers to conclude that the high intensity sprints are working through a mechanism separate from simple caloric expenditure. If you are familiar with the metabolic effect then you already know this mechanism involves hormones NOT calories. In an ideal world we would incorporate sprints and walking, but when you are limited on time, it is important to understand that even a few short intense bursts of activity can have profound impacts on your health and risk of diabetes. To read this article online for free follow this link: http://www.biomedcentral.com/1472-6823/9/3

**NOTE** If you are not used to high intensity exercise please consult with a doctor and start slowly. A “sprint” is different for everyone and can be adapted to fitness level. For a 90 year old grandfather a “sprint” may be walking briskly across the room. But for an elite athlete it may be an all out burst of speed. The point is to exert your self to the point of breathlessness then stop and rest and do it again. “Push until you can’t, rest until you can” is a good guide to keep it safe. Listen to your body and be safe!

References:

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2. Dengel DR, Pratley RE, Hagberg JM, Rogus EM, Goldberg AP: Distinct effects of aerobic exercise training and weight loss on glucose homeostasis in obese sedentary men. J Appl Physiol 1996, 81(1):318-325. PubMed Abstract

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4. Katzel LI, Bleecker ER, Colman EG, Rogus EM, Sorkin JD, Goldberg AP: Effects of weight loss vs aerobic exercise training on risk factors for coronary disease in healthy, obese, middle-aged and older men. A randomized controlled trial. JAMA 1995, 274(24):1915-1921. PubMed Abstract

5. Lampman RM, Santinga JT, Savage PJ, Bassett DR, Hydrick CR, Flora JD Jr, Block WD: Effect of exercise training on glucose tolerance, in vivo insulin sensitivity, lipid and lipoprotein concentrations in middle-aged men with mild hypertriglyceridemia. Metabolism 1985, 34(3):205-211. PubMed Abstract

6. Lampman RM, Schteingart DE, Santinga JT, Savage PJ, Hydrick CR, Bassett DR, Block WD: The influence of physical training on glucose tolerance, insulin sensitivity, and lipid and lipoprotein concentrations in middle-aged hypertriglyceridaemic, carbohydrate intolerant men. Diabetologia 1987, 30(6):380-385. PubMed Abstract

7. Potteiger JA, Jacobsen DJ, Donnelly JE, Hill JO: Glucose and insulin responses following 16 months of exercise training in overweight adults: the Midwest Exercise Trial. Metabolism 2003, 52(9):1175-1181. PubMed Abstract