(20-06-10) How Much Exercise Is Enough?

by DR. JONNY ? 10 COMMENTS

A new study in the Journal of the American Medical Association is making
people nuts.

If you don?t read the actual study and only listen to the sound bite headlines
in the media, you?d walk away thinking that women need at least an hour a day
of exercise to keep weight off. That?s understandably discouraging for a lot of
people, especially those with busy lives. It also is about twice the current
federal guidelines of 150 minutes a week (or 30 minutes five days a week).

And it?s partly true? but God is in the details.

Let?s start with the federal guidelines, (30 minutes of moderate-to-intense
exercise, 5 days a week). Those were meant to prevent disease. And a ton of
research has shown that walking at a moderate clip five days a week for a half
hour at a time will do just that. That kind of exercise will indeed lower your
risk for dying, improve your heart health and actually- according to research
at the University of Michigan- even grow new brain cells!

But- as I?ve said many times- it won?t make your body bikini ready, and for
many people it won?t result in weight loss at all.

To prevent weight gain, you need a lot more. A 2002 report by the Institute of
Medicine suggested 60 minutes 7 days a week for that purpose, closer to what
the present study found.

But- and this is a really big but- there?s one important detail that everyone
reporting on this study seems to have forgotten: diet.

In the current study, diet wasn?t monitored at all. The researchers reported
on the amount of exercise it took to keep weight off for women ?eating a normal
diet?.

A normal diet?

In America?

You?re kidding, right?

Nope.

As trainers like to say, ?you can?t outtrain a bad diet?. So if you don?t
tackle the eating issue, it?s gonna be really hard to lose (or even maintain)
weight with exercise alone. Unless, of course, you?re Michael Phelps.

In defense of the researchers, they didn?t just accidentally ?forget? to
control for diet. They wanted to see how much impact physical activity alone
would have on weight assuming people didn?t change the way they eat.

And the answer was: not all that much.

Truth be told, exercising alone- without dietary changes- did help a bit,
particularly for women who weren?t very overweight to begin with. For those not-
too-overweight women, about 60 minutes a day kept weight gain to a minimum over
the course of the fifteen-year study. But 60 minutes had less of an impact on
people who were significantly overweight to begin with, which makes sense,
since without dietary changes we can assume these women were eating an awful
lot to begin with and were continuing to do so throughout the length of the
study.

So the bottom line is not that exercise doesn?t matter- it most certainly
does. It?s just not enough to get the job done if you don?t make some serious
changes to the way you eat.

Unless of course, you are Michael Phelps. Then I guess you can eat whatever
you want.

As long as you spend 8-10 hours a day training.

Source: jonnybowden.com

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In evidenza

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Per coloro che hanno problemi di salute si consiglia di consultare sempre il proprio medico curante.