Once you start to understand the science behind a lot of diet, nutrition and health science publications, you realize that it’s rare for the recaps of science in the newspaper to accurately depict a scientist’s results or a study’s real-world implications. I’m not trying to take a shot at all health journalists – just a large number of them. I think they need to be called out for their shoddy reporting and exaggeration techniques. Take, for example, a recent study published in the Journal of Physiology. From the headlines it made, you’d think that scientists have stumbled upon a miracle workout regime:

Short bursts of exercise will make you fitter quicker

10 minutes of fast sprints beat 10 hours of cycling

Short blasts of exercise as good as hours of training, scientists find

And, my personal favorite:
The secret of keeping fit? Do less exercise

Marathon or sprint? (credit, Frederic de Villamil, flickr)

Read a few paragraphs into each and you’ll be told that science has revolutionized how people should work out. “Alternating short bursts of intense activity with brief rest periods delivers more benefit for less exercise, research shows.” “A set of ten one-minute sprints on an exercise bike three times a week holds the same benefits as ten hours of ‘conventional’ distance cycling.”

Indeed, the articles even tell you that: “Tests afterward showed that their muscles had improved as much as if they had been involved in endurance training.”

The bottom line: research has reportedly shown that by working out for just ten minutes three times a week, you can be as in shape, if not more so, than quadrupling the standard thirty minutes a day five days a week.

Here’s a hint: if it sounds too good to be true, it probably is.

The Research: What They Did

All of these articles center around a recent paper in The Journal of Physiology titled, “A practical model of low-volume high-intensity interval training induces mitochondrial biogenesis in human skeletal muscle: potential mechanisms.” It centers around a recent fashion in workouts called High-Intensity Interval Training, or HIT. HIT is a method of exercise which involves working as hard as you can for brief intervals followed by brief rest intervals. For example, you might sprint for a minute and then jog for thirty seconds, and repeat this for a half and hour. The idea is that by doing higher intensity workouts for shorter time intervals, you can work out “less” but get the same, or even more, benefit.

Of course, that’s not what this study showed. The study at hand followed seven men with an average age of 21 through a two-week, lower-intensity HIT training regimen where volunteers rode a stationary exercise bike for 12 cycles of 60 seconds of peddling above their comfort zone followed by 75 seconds of rest. The researchers tested the volunteers’ levels of a number of fitness variables, including cycling time trials and the activity of exercise-related enzymes like citrate synthase and cyctochrome c oxidase. They also tested for increases in muscle glyocgen, GLUT4, and PGC-1α, which is a transcription factor that is proposed to be upregulated during muscle creation.

In a vast sweep, they found that the training increased everything that could be associated with increasing muscle and being more fit. They state that:

“this study demonstrates that a practical model of low volume HIT is a potent stimulus for increasing skeletal muscle mitochondrial capacity and improving exercise performance.”

The Research: What They Didn’t Do

You might have noticed that there’s no mention of what happened to the group that did 10 hours of moderate exercise instead of the HIT training regimen: that’s because it didn’t exist. The study did not, in any way shape or form, compare HIT to regular training techniques. Where did the headlines get the idea that this somehow beat 10 hours of conventional exercise? That’s a good question, because it isn’t in the paper. The paper’s last remarks are that future studies need to look into this type of exercise in further depth, “to determine whether this type of training is an effective health-enhancing exercise strategy.”

The Tortoise or the Hare? This study did nothing to clear up the debate.

The news coverage would have you think that this training method is somehow better than how you might normally work out, and yet the study doesn’t compare it to any kind of normal workout regime. They don’t even try to compare their results to other studies. They simply state that working out this way can be good, too. And are you surprised that adding an additional 15-30 minutes of high-intensity workouts a few times a week improves your health? After all, shouldn’t adding any kind of exercise improve something?

That’s not to say that high-intensity training isn’t potentially better than longer, low-intensity training. Studies have shown that improvements in many exercise variables are directly related to intensity, duration, and frequency of training. In short, the harder you work, the better it is for you, and you don’t have to work as long to achieve the same results. In principle, this makes sense: a half hour run is going to do more for you than an hour walk. The question is how hard do you have to work for how long and how often to get the kind of results you want – and the answer to that isn’t anywhere in this paper.

The point is that this study didn’t test how long moderate training took to equal the interval training results, or compare the interval training to a given, conventional training regimen. It didn’t show that HIT improved fitness more or less than any other method, nor more or less quickly. For that matter, it worked with young, fairly in shape men, so its application to the masses is very limited. Is it better for a 60 year old, overweight woman to undergo a HIT workout than power walk around her neighborhood every morning? No one knows – it hasn’t been studied.

Don’t Judge A Study By Its News Coverage

The take home message is that you can’t believe everything you read in a newspaper. Scientific studies are, more often than not, couched in a way that the journalists will think is eye-catching, even if it distorts the actual study’s findings. The goal of these journalists isn’t to pass on vital information. It’s to gain as many readers as they can without being so false as to get in trouble. Indeed, sensationalized headlines get attention, but they do so in the wrong way. They make the science unimportant and diluted, and lead to a mistrust of scientific research. After all, if every day you’re told that scientists are a day away from curing cancer, but a cure still isn’t there, you start to think that the scientists are full of crap. But it’s not the scientists that are full of it – it’s the journalists that blow findings out of proportion and skew results in whatever way they think will sell articles. Even worse, the mainstream journalists do so without linking to the actual studies – meaning you can’t even click on a link and read the paper’s abstract to see if the article written about it is doing it justice. That’s simply unacceptable.

Little, J., Safdar, A., Wilkin, G., Tarnopolsky, M., & Gibala, M. (2010). A practical model of low-volume high-intensity interval training induces mitochondrial biogenesis in human skeletal muscle: potential mechanisms The Journal of Physiology, 588 (6), 1011-1022 DOI: 10.1113/jphysiol.2009.181743