Welcome to Straight Talk on Health. I’m your host Dr. Chet Zelasko. Straight Talk on Health is a joint production with WGVU in Grand Rapids MI. I examine the world of health. Nutrition. Exercise. Diet. Supplementation. If there’s something new, I look at the science behind them, and let you know whether it’s real or not. You can check out other things that I do on my website Drchet.com and sign up for my free emails.
If you've paid attention to fitness news or have talked to exercise professionals, one of the things that they say is that there is no such thing as spot reduction. By that I mean you cannot target a specific area of your body, let's say your abdominal area, and lose fat by doing a targeted exercise such as sit-ups or leg lifts. You can make the muscles underneath the skin stronger for sure. But there doesn't seem to be any evidence that you can reduce the amount of fat in that area.
With 35 years of experience in the field, I would say that that requires a qualified answer. It needs to be qualified with the word yet. There hasn't been a study that proves that you can reduce fat in a specific area yet. Is it theoretically possible? Yes, I think it is. The problem is the quantity of exercise focused on one area long enough per workout session to do be effective. It may be that we've approached it all wrong by focusing on resistance exercise. Let's take a look at another study that compared high intensity interval training (HIIT) on a cycle ergometer versus a treadmill.
Researchers began with two questions. Is there any difference in the fat mass in specific areas of the body after training using a cycle ergometer or a treadmill? In addition to that, they wanted to know if there was any change in beneficial microbes in the microbiome after training. Let's take a look at what they did.
Researchers recruited 16 men with a mean age of 54 years and initial BMI of 29.9. They randomly assigned them to either a cycling group or a running group. After assessing initial fitness level, body fat and body fat distribution using the DEXA scan, and taking an initial stool sample for analysis of the microbiome, the subjects were randomly assigned to the bike or the treadmill. To make sure that there were no significant changes in diet, the subjects were required to maintain their typical diet and do 7-day diet records periodically during the study.
The HIIT bike program required them to do 10 intervals for 45 seconds each at 80 to 85% of the maximal heart rate and then a 90 second active recovery, or a HIIT run program which was 9 intervals for 45 seconds at 80 to 85% of MHR and again with 90 seconds of recovery between intervals. They were to do this exercise under supervision three times per week for 12 weeks. The goal was to have all exercisers use the same number of calories during the workouts whether cycling or running hence the difference in number of intervals. The subjects were then retested to examine any differences.
What they found was that there were reductions in overall weight as well as abdominal and visceral fat. What’s the difference? That which is just under the skin is abdominal fat and that which is under the abdominal muscles and around the internal organs is visceral fat. That type of fat is more related to the development of CVD and type 2 diabetes. There were no differences in the outcome variables with two exceptions.
Those who were in the running group lost a greater percentage of abdominal fat than did the cycling group at 16.1% vs. 8.3%. The other difference was that positive changes in the microbiome were correlated with the loss of abdominal fat. Before you get too excited, the actual loss of abdominal fat was close to 2 pounds in the running group and about 1 pound in the cycling group. As a former runner, running still rules.
The other benefits were an improvement in some positive bacteria in the microbiome. It wasn’t associated with running or cycling; it was correlated with the loss of abdominal fat. It seems that visceral fat would show more benefit but that wasn’t the case. Maybe someday we’ll find out why. For now, we know what is.
The obvious problem for doing a running HIIT program is that you have to be able to run—at least for 45 seconds. While my running is progressing slowly, I only do an interval approach while walking or riding the exercise bike. 45 seconds? I can handle that.
The researchers didn’t have a reason to explain the difference between cycling and running when it came to the loss of abdominal fat. I’ll hazard an informed opinion. Running integrates more of the core during the actual interval than cycling does. That could be tested with sensors that detect electrical activity of muscles. But that’s fine tuning that might not be necessary. It’s not important why; it’s just important that it is.
We’ve seen that a HIIT running program can help lose abdominal fat in those that are overweight. How about getting fitter faster? Is that possible?
Keeping with the theme of using interesting training techniques, this next study took it one step further. The objective was to see how fast subjects could get fitter using a sprint interval training program. In the classic sense, when exercise physiologists talk about fitness, they mean how much oxygen your body can use at maximal levels. It’s called Max VO2.
To test whether or not someone could become fitter in as little as two weeks and continue to increase their fitness level through the 6 weeks of a training program, researchers recruited a group of 18 sedentary men with a mean age of 23 years. Five subjects dropped out over the course of the study.
While prior research had used 30 seconds of sprinting with 4 minutes of easy moving, the researchers chose 15 second intervals with 2 minutes of easy pedaling and rest before the next interval. After a physical including an ECG, the subjects were allowed to practice the sprint rest cycle twice before the actual program began. There were three cycles of workouts that went like this: They began with the Max VO2 test to determine the resistance in the sprints. Then, in succeeding workouts scheduled every 2 days, the number of intervals per session began at 10 sprints, then 2 sessions at 12 repetitions, a session of 14 sprints, and finishing with 8 sprints. Then, the cycle repeated.
What did they find? There was an 11% increase in Max VO2 after the first cycle, reduced down to 6.4% after the second cycle and finished at an 8% increase. Were they fitter? Max VO2 notwithstanding, they absolutely were fitter. The reason we know that is because during succeeding sessions, their heart rates were lower for a given workload. They were working just as hard but they didn’t need to use as much energy to do it.
I think that’s what happened during the sprint interval training study. The improvement was greatest after the first cycle and then it rescinded slightly. There was another reason I think the results were stymied: they overtrained. Athletes would do intervals of any types once, maybe twice per week. The subjects trained every other day for 6 weeks—and the Max VO2 test is like one of sprint training sessions. If someone were healthy enough and with doctor’s permission, doing a sprint interval training session once every two weeks is enough. I know it sounds so easy: it’s just 15 seconds! I get to rest for 2 minutes. Trust me, with 30 years as a runner and an exercise physiologist: you get shredded every time you do it. You need complete recovery after you that kind of session whether cycling, sprinting on a track, on an elliptical, whatever.
I hope you’ve enjoyed the progression of these recent studies but I’m all out of time. This is Dr. Chet Zelasko saying health is a choice. Choose wisely today and every day
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