Tag Archive for: max VO2

SIT to Get Fitter

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Here are the results of the study on sprint interval training or SIT. 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 the subjects 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.

Is there an explanation for the apparent dip in the max VO2 increase? I think the reason the results appear stymied was that they overtrained. Athletes do intervals of any type once, maybe twice per week. The subjects trained every other day for six weeks—and the max VO2 test is like another sprint training session. If someone were healthy enough and had the 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 two 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 that kind of session whether cycling, sprinting on a track, on an elliptical, or whatever.

The Bottom Line

I hope you’ve enjoyed the progression of these recent studies. From a walking program to get fitter and sustain muscle mass in exercising muscles, to the comparisons of bike HIIT intervals versus running HIIT intervals to sprint intervals to get fit a little faster, there’s something for everyone. Just make sure you have your physician’s approval to exercise at the level of each type before you begin.

What are you prepared to do today?

        Dr. Chet

Reference: Medicine & Science in Sports & Exercise. 56(5):876-884, May 2024.

Sprint Interval Training

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Keeping with the theme of using interesting training techniques from the last Memos on HIIT training, 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.

I think I need to define some terms here. When we talk about getting fit, there are different types of fitness. There can be tests of strength like lifting the most amount of weight in a bench press. There can be tests of stamina such as how many push-ups a person can do. But when exercise physiologists talk about fitness in the classic sense, 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 six weeks of a training program, researchers recruited a group of 18 sedentary men with an average age of 23; five subjects dropped out over the course of the study. The reason the researchers chose this particular research topic was because prior research had shown that the initial gain in fitness was not increased further with continued training.

While prior research had used 30 seconds of sprinting with four minutes of easy moving, the researchers chose 15-second intervals on a bike with two 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 two days, the number of intervals per session began at 10 sprints, then two sessions at 12 repetitions, a session of 14 sprints, and finishing with eight sprints. Then the cycle repeated.

What did they find? Were they fitter? You bet they were, but I’ll save the details for Saturday.

Insiders, I’ve changed the conference call date from June 12 to June 19. Being an Insider allows you to get details that would be too time consuming in Memos. For example, I’m researching omega-3 supplementation in light of all the recent studies questioning its use. I want to find out what’s going on, and I’ll talk about it a week from Wednesday.

What are you prepared to do today?

        Dr. Chet

Reference: Medicine & Science in Sports & Exercise. 56(5):876-884, May 2024.