Yesterday the Journal of the American Medical Association (JAMA) put out study results in which they indicated that women, particularly us mature women should exercise 60 minutes a day just to prevent weight gain.

WHAT?

I don’t believe that’s true – it hasn’t been for me.  I do exercise a good 60 minutes a day 5 days a week but I’m also losing weight at that level of exercise.  So why is it that I, a woman over 50, can lose weight doing 60 minutes of exercise 5 days a week when the study suggests that I would need to work out an hour 7 days a week just to keep even?

So I dug up the study and read it.  And  a couple of things popped out at me.  First, on the good side there were a lot of women participating (over 34,000).  The median age of the women was 54 at the beginning of the study and it ran for 15 years.  So unlike some studies that have relatively few people participating or are conducted over a short period of time, this one should have data we can believe.

But I was still uncomfortable with the results.  So I read further and I believe that I can point to two issues with the study.  First the women self reported at specific intervals.  Now self reported data is less reliable by its nature.  But worse yet, when you looked at the brackets of hours that the women had to choose from, it seemed to me like it would tend to get the women to select the one that would yield the hour a day recommendation.  Here are the brackets provided:

• Less than 7.5 hours per week
• 7.5 hours to 21 hours per week
• Over 21 hours

Now if you ask most people how long they work out, how many actually keep the eye on the clock for the actual exercise period rather than the time they spend in the gym in total?  Go to the gym and it takes 5 minutes to change clothes and hit the floor.  Then look for the open treadmill or other equipment you want to use, hope it’s open and get on it.  Warm up (should that be counted?), then get in the core of the exercise only to cool down (should that be counted?) and head off to the lockers again.  Who knows what happens to the time count if you see a friend and start a conversation.

On any given day the actual time spend may be far less than an hour but most people will average up in time when they report.

My next issue was the type of exercise.  It was ‘moderate intensity’ exercise.  The report is not as clear as it could be on what that is but let’s assume we are talking about treadmill walking at a brisk pace or using the eliptical trainer or other cardio workout option.

I’m a bit believer in doing high intensity workouts at least 3 – 4 times each week.  Then a lower (i.e., moderate) intensity workout is fine for the other workouts.  Specifically I urge women to do more strength training.  Working out on a treadmill or taking an aerobics class won’t add muscle.  And since we’ll lose muscle as we age unless we do incorporate resistance (i.e., strength) training, it’s likely that those women were losing muscle mass.

And that’s the real issue.  Loss of muscle mass will require longer and longer bouts of moderate intensity exercise just to stay even.

I had wished the JAMA study had gone further to seperate women into groups of moderate intensity and a blend of high and moderate intensity exercisers.  Then I think we would have gotten dramatically different results.

Those of you who know me, know I highly recommend P90X as a fantastic workout program that will get you in the best shape of your life.  It takes a little over an hour a day 6 days a week.  And you do have to watch what you eat to get best results.  But seriously, it sure beats walking on a treadmill just to stay even in the battle against fat – doesn’t it?