Saturday, October 17, 2009
Cardio vs. Fat Burning modes -- good information to know
Q. We have several workout machines in our office and I want to use them, but I'm confused about the different heart rate zones. What zone should I be training in to lose weight?
A. This is a great question that many people ask. It is important to realize that the body has two different fuels it converts to energy: carbohydrates and fats. The body burns these fuels in different proportions depending on your fitness and the intensity of your workout. Your body stores fewer carbohydrates than fat, yet it accesses the carbohydrates more easily. So the goal is to make your body more efficient at burning the stored fat while sparing the carbohydrates. Working out at higher heart rates [70 to 85 percent] will burn more carbohydrate calories in the short term, but it is working out in the lower zones [60 to 70 percent] that trains your body to become efficient at fat burning. In turn, this improves your endurance and aerobic fitness, eventually leading to a faster metabolic rate during exercise. This means that over time, you can burn as many calories at a low intensity as you were previously burning at a high intensity. With proper training this can happen in as little as three to six months.
Therefore, the best intensity for weight loss is one that seems 'fairly light' to 'somewhat hard'. Often people who cannot lose weight, or who even gain weight despite high intensity exercise and restrictive dieting, find success through a combination of slowing down their exercise, and improving the quality of their diet. This approach is not only more effective, but it's more fun and easier to stick to long-term!
-- Emily Cooper, M.D.
I sometimes tend to find it hard, actually, to keep my heart rate low enough to be in the fat-burning zone. I think a lot of that has to do with the fact that I haven't exercised consistently or long enough for my heart to be strong enough to beat at a slower rate when exercise is introduced, but I have noticed in the past that it only takes a few weeks of moderate exercise about four times a week (or more) for my heart to respond accordingly. I had times when I was younger and more fit that it was hard to get it up into the cardio zone.
So for a while now, I will work at getting and keeping myself in the fat-burning zone (since I have SO much to burn) and see how I feel about it.
Posted by Beth at 4:08 PM