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When the exercise is intense, even a little can offset the dangers of sitting all day. A. Pawlowski, TODAY, 5/7/2020 4-Second Sprints Supercharge Metabolism Edward F. Coyle, PhD, professor of kinesiology and health at the University of Texas, Austin, and his graduate students in the Human Performance Laboratory have taken another important step forward in their exploration of high intensity exercise. When I began thinking and writing about high-intensity intervals years ago, I came on an invited editorial by Professor Coyle in the Journal of Applied Physiology explaining why high-intensity intervals are twice as efficient as steady state aerobics. Common sense when you understand it. Simply put, high-intensity intervals increase the capacity of all muscle fibers, fast and slow, while steady state aerobic training leaves half of the fibers unused and untrained. It’s like pulling a wagon with one horse, when two would get you a lot farther down the road. The new study probes further into that advantage. * * * What’s more, we were honored to have Professor Coyle launch the conference at the Stark Center for Physical Culture and Sports on the occasion of my 75th birthday and publication of our 10th book Take Charge. He led the panel on the Aerobic/Strength Alliance. You’ll find a photo of him and full details on our Fitness Personalities page: https://www.cbass.com/AustinConf.htm A fortuitous follow-on was that Professor Coyle gave us a heads-up on his innovative 4-second intervals. You’ll notice the focus on fast-twitch muscle fibers: You’ll be pleased to know that since we last met in Austin a few years ago, I've begun to study aging and muscle and sarcopenia. I’m training men and women 50-70 y for 10 weeks. They are training on an ‘Inertial Load Ergometer’ we’ve developed. It involves an all-out sprint on this unique exercise bike that lasts for about 4 sec. The only resistance on the flywheel is its inertial. Thus, it requires high force to get it moving, high power for maximal acceleration and high velocity to achieve a final RPM of 150-220. Essentially, it is constant acceleration. As you state in the newsletter, maximal neuro-stimulation for ‘trophic’ factors is as important as muscle tension and power. We have data indicating that fast-twitch muscle fibers are especially responsive to even an acute bout of acceleration exercise. Of course, sarcopenia is mostly a loss of fast-twitch fibers as most people stop moving fast and powerfully after age? (25y? 50y?). I’m sorry to be preaching to the ‘minister.’ You’ll find that preface helpful in digesting the new study. * * * We should also revisit a study by Professor Coyle and his team published February 14, 2019 in the Journal of Applied Physiology. We reported the results on our FAQ 13 page: Healthy, physically active graduate students who sat for long periods developed metabolic problems that appear to override the benefits of exercise. These data suggest "that people who exercise in compliance with general activity guidelines but remaining inactive for prolonged periods during the day are still at increased risk for cardiovascular disease and premature death," the researchers concluded. Ten students (5 male and 5 female) completed a crossover protocol to determine the impact of an acute bout of exercise on their metabolism after prolonged sitting. Four days of prolonged sitting (~13.5 hours a day) without exercise were compared with 4 days of prolonged sitting with a one hour bout of treadmill exercise on the evening of the fourth day. On the morning of the 5th day (with and without exercise), the students were given a large breakfast shake composed of half-and-half cream and melted ice cream, following which blood was collected over a six hour period and analyzed for triglycerides, glucose, and insulin. "No differences between trials were found in the overall plasma triglycerides, glucose, or insulin responses during the high-fat/glucose tolerance tests," the researchers reported. "These data indicate that physical inactivity (sitting ~13.5 h/day and <4,000 steps/day) creates a condition whereby people become 'resistant' to metabolic improvements that are typically derived from an acute bout of aerobic exercise." * * * The new study continues that line of inquiry—using Professor Coyle’s Inertial Load Ergometer. 4-Second Sprints in Action As Professor Coyle and his team had demonstrated, an hour on the treadmill doesn’t overcome the effects of too much sitting. (As he had explained earlier in his invited editorial, steady state aerobic exercise leaves fast muscle fibers unused and untrained.) Enter Coyle’s special ergometer with a heavy flywheel, which triggers fast-twitch fibers within 4 seconds, by going slow and hard at first, then fast with less resistance. (The important difference between the Inertial Load Ergometer and a standard stationary bike, Coyle explains, is that the ordinary home bike lets riders accelerate too quickly and recruits few, if any, fast fibers.) The hypothesis was that five 4-second sprints every hour—160 seconds of all-out exercise per day—would metabolize fat more efficiently and lower triglycerides compared to sitting all day. That’s what they found, using the same crossover protocol as before. Four men and four women participated in two trials: SPRINTS and SIT. The trials consisted of an 8-hour period of sitting (allowing participants to get up only to eat or use the bathroom), or an equal sitting time interrupted by five sprints every hour. To determine how their bodies responded to a high fat meal the next day, blood was drawn after they drank a mixture of melted ice cream and heavy whipping cream the next morning. “No differences between interventions were found for plasma insulin or glucose. However, SPRINTS displayed a 31% decrease in plasma triglyceride and a 43% increase in whole body fat oxidation when compared to SIT.” They concluded: “These data indicate that hourly very short bouts (4 s) of maximal intensity cycle sprints interrupting prolonged sitting can significantly lower the next day’s postprandial plasma triglyceride response and increase fat oxidation after a high fat meal in healthy young adults. Given that these improvements were elicited from only 160-s of non-fatiguing exercise per day, it raises the question as to what is the least amount of exercise that can acutely improve fat metabolism and other aspects of health.” Keith Diaz, an assistant professor at Columbia University Medical Center in New York, who studies the dangers of too much sitting, talked to TODAY about the Coyle study. Muscles are important for controlling blood sugar and triglycerides, he explained; when people don’t move, this process doesn’t work effectively. Really intense, all-out exercise that uses almost all of your muscle will combat this, he said, noting that it was particularly striking how brief the workout were in the study. “This could be good news for many sedentary adults who have limited time in their day and may not be able to get to the gym. Of course, the caveat is that the exercise was an all-out effort,” Diaz added. Professor Coyle countered by calling 160 seconds of four-second sprints spread over the course of a day “not much exercise at all.” As indicated in the study, SPRINTS on the special ergometer are "non-fatiguing." My Take Short of buying special bikes for home and work, attempting to replicate the study protocol may not be feasible. Professor Coyle does, however, believe that the underlying principle has wide application. “When you find yourself sitting for most of the day, try to rise frequently and move, preferably intensely, as often during the day as possible and for as many seconds as you can manage,” he told the media. Closer to home, the study is more support for the lifestyle Carol and I have led throughout our married life. A major reason she married me was that she believed I was on track to lead an active life. I was impressed by the fortitude she showed biking up a steep hill shortly after we began dating. We’ve never stopped exercising and eating healthy. Our life is full of movement—in and out of the gym. She records more steps than me, but I’m more sensitive to the need for intensity and to keep blood flowing in the brain. Getting up and moving around helps me concentrate while writing pieces like this. Exercise—especially high-intensity—truly is the best medicine. Even a few minutes—or seconds—daily can help keep us healthy and in good spirits.
Photo by Denie Walter June 1, 2020 Comment on this article: FEEDBACK Ripped Enterprises, P.O. Box 51236, Albuquerque, New Mexico 87181-1236 Home | Products Index | Ripped Bks | Lean Adv. Bks | Lean For Life | Recommended Bks | |Consultations | Posing Suits | Tapes | To Order | Feedback] Copyright © 2020 Clarence and Carol Bass. All rights reserved.
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