2012-02-16

Pop Fitness

The New York Times health blog reports that even very minimal amounts of interval training have good positive impacts on the body.
Several years ago, the McMasters scientists did test a punishing workout, known as high-intensity interval training, or HIIT, that involved 30 seconds of all-out effort at 100 percent of a person’s maximum heart rate. After six weeks, these lacerating HIIT sessions produced similar physiological changes in the leg muscles of young men as multiple, hour-long sessions per week of steady cycling, even though the HIIT workouts involved about 90 percent less exercise time.
Then, this:
The results, published in a recent review of HIIT-related research, were especially remarkable in the cardiac patients. They showed “significant improvements” in the functioning of their blood vessels and heart, said Maureen MacDonald, an associate professor of kinesiology at McMaster who is leading the ongoing experiment.
What They Want You To Think
This report, like virtually all fitness reporting out there, uses clinical studies of sedentary people to demonstrate levels of health improvement as compared to a control group of people who do not exercise, or the same group of people prior to their undertaking a new fitness regimen.

The take home message appears to be that interval training twice or thrice a week is "just as good as" extended periods of cardiovascular workouts that occur more often.

And the general public drinks the Kool-Aid. They believe they have found a magic bullet. They think that getting fit is as simple as doing 20 minutes of exercise two or three times per week. And all this time they thought that they had to work out more than that! No, these studies apparently say, all they have to do is a bare minimum of effort and they will soon be just as fit as young men who do "multiple, hour-long sessions of steady cycling."

And here, science has proven it, right? QED! Ask no more questions. Pay no attention to the man behind the curtain.

What You Should Actually Think
As I said, these studies involve sedentary people who take on a new exercise regimen. The important take-home message here is that, obviously, exercise of any kind is better for you than no exercise at all.

But here's the other thing: different kinds of exercise affect people differently depending on their current average level of activity and the amount of time they have been engaging in any given exercise regimen.

What I mean is, if you never do any kind of interval training, and then suddenly begin an interval training program, you will see a rapid and near-immediate physical impact. Your body will respond to the new stimuli it encounters. This progress will naturally increase at a decreasing rate until you have captured all the gains from any particular activity, up to the point where you reach a physical plateau. Once you hit that plateau, you will have to change your exercise regimen to see any additional progress.

There are two key points here:

First, the gains of any new exercise regimen are limited, and once you capture them, you must either choose a new regimen or increase the intensity or frequency of your existing regimen. That means that once you've done interval training for a few weeks, you will no longer see additional benefits. At that point, interval training no longer has the same kind of superiority over other forms of exercise that it did when you first started interval training. Your body has adapted to it and changed. It has become more efficient and requires less energy to perform the same interval training activity. You've plateaued.

Second, you would have experienced a set of gains by taking on any new exercise regimen at all, not simply an interval training regimen. That means that you could have lifted weights three times a week, or gone for a 5km run every morning, or gone to a bi-weekly spin class, or gone for a series of hikes, or anything. Whatever your regimen happens to be, you will experience a set of gains. And each type of exercise offers you a different set of gains. One isn't "superior" to the other, merely different.

That second point is why most really good exercise programs involve a combination of strength training, endurance training, interval training, and rest.

The point is that interval training my produce a good set of results if you go from nothing to something, but so will any other kind of exercise regimen, and like all them, once you've captured the initial gains, you have to move on to something else in order to maintain a given level of fitness.

No Magic Bullets
So there is no magic bullet here. Interval training won't prevent you from having to do endurance training, it will merely do the good things for you that interval training does - and vice-versa. Just because some study suggests that walking burns more calories for obese people than running does, that doesn't mean that walking burns more calories for me than running does.

Get it? You can't cheat with exercise. Despite all claims to the contrary, there is no clinical evidence that suggests that people can sub-in multigrain bread for white bread, do 20 minutes of exercise twice per week, and suddenly become as fit and sexy as a person who eats perfectly and exercises 6-7 days per week, multiple times a day.

No shortcuts! No gimmicks! Fitness is a lifestyle, not a temporary plan to go from zero to hero. It takes years of consistent work to get truly fit, not a few weeks of interval training.

Don't be fooled by pop fitness!