Cardiovascular Intensity

Cardiovascular exercise intensity can be tracked by using your "target heart range." To determine your personal target heart rate, subtract your age from 220. This is your estimated maximum heart rate level. Your heart probably won't actually explode or anything if you go over that number, I've done it a few times, but you'll probably feel sick, dizzy, and weak.

Your maximum heart rate represents 100% effort. Very few people, even highly trained athletes, can maintain that level for very long. The level where you'll want to exercise depends on your goals. As I mentioned in a previous post, this summer I worked myself pretty hard, a lot of high intensity cycling, hard and fast. I noticed that the exercise was getting a lot easier, my resting heart rate slower, and overall I felt better, but I was rather disappointed with the slowness of my fat loss results. That's because I was exercising over my anaerobic threshold.

Your anaerobic threshold is the point where your body stops burning fat for fuel and switches over to the faster burning carbohydrates. For most people this happens at about 75% of their maximum heart rate. So if your goal is fat loss, you'll want low to moderate-intensity exercise = 60% to 75% of your estimated maximum heart rate level. For me, at 39, my maximum heart rate is about 181. So for the best aerobic fat burning workout, I want to keep my heart rate between 109 and 136. So now on a long haul ride, I'll hit a groove right around 125 beats per minute. I'll still throw in some peak efforts to work my heart, though.

High-intensity exercise = 80% to 90% of your estimated maximum heart rate level, will help strengthen your heart and lungs. For me, this is the 145-163 range. At this level our bodies burn more carbohydrates than fat during the exercise, but burn more fat the rest of the day than if we don't exercise at all. However, if you're burning carbs, you have to make sure that you keep your body supplied with them or it will go into a semi-starvation state, and slow down your metabolism.