Thanks to all of you who wrote in response to the blog post on heart rate changes for women. When we get questions we know we're being read!
The most frequent question we got was whether or not the target heart rates would change depending on whether or not you are physically conditioned. The answer is no, and here is why.
Your heart is a muscle. Its job is to pump blood through your body. One of the reasons you should exercise is to make that muscle stronger. When your heart is strong, it can pump the same amount of blood with fewer beats. That is why, when you are in good physical shape, your resting heart rate usually drops…because your heart has become more efficient at doing its job.
Simply reducing your heart rate by one beat per minute saves you 525,600 heart beats per year!
Another really good sign that you're in good condition is that after you finish that exercise, your heart rate drops back to resting fairly quickly. In research times, you've improved your recovery rate. When you're out of shape and you start to exercise, you may find that you have an elevated heart rate long after your workout.
So if your heart is able to pump the same amount of blood with fewer beats when it is in good condition, it is going to be more difficult to get it to speed up its pace when you are exercising. The heart rate recommendations stay the same because your physical conditioning make it harder for you to stress your heart muscle.
One way you can challenge your heart is to switch out the kind of exercise you do, to use different muscle groups. Like your heart, other muscles can become accustomed to the workload and not have to work as hard to carry the same load.
The heart rate guidelines are a percentage of the maximum rate your heart rate should ever reach. So if you're having to work harder to max out your heart's capacity…you're in good shape.
The guidelines do NOT tell you what your maximum exercise rate should be. What they do indicate, is that if you are exceeding those guidelines, you're likely not burning fat and finding it harder to lose weight. You're also likely to be gaining weight in the form of muscle, glycogen, and water, to support that intensity of exercise.
You need to decide what your goal is. If you want to build muscle (and that's not a bad thing at all), then work out harder. If you want to burn fat, remember, more is not always better.
And keep that heart muscle pumping!