Knowing your heart rate can help with training routines

I've been doing a lot of cardio lately at different intensities and I'm interested in knowing what my target heart rate should be. How do I go about figuring that out? -- Ezra Fishman, class of 2005



The first thing you need to figure out is your maximum heart rate. This is estimated by simply subtracting your age in years from 220. So a 20-year-old individual would estimate their maximum heart rate to be 200 beats per minute. This number is your age-predicted maximum heart rate (APMHR).

There are two nearly equivalent methods for determining target heart rate after obtaining your APMHR. The first, and easier, method simply multiplies your APMHR by your exercise intensity as a percentage of your maximal intensity. For example, if the 20-year-old described above likes to work out between 60-70 percent of his or her maximal intensity, then his or her target heart rate range will be between (0.60 x 200) and (0.70 x 200) or between 120-140 beats per minute.

The more comprehensive but more complex method, called the Karvonen method, involves knowing your resting heart rate in addition to your maximal heart rate. First, obtain your APMHR, which is 200 beats per minute for our theoretical 20-year-old person. Now subtract your resting heart rate (RHR) from your APMHR to get a quantity called the heart rate reserve (HRR).

The target heart rate is found by multiplying the HRR by the desired exercise intensity and then adding the RHR. Assuming our 20-year-old individual has an RHR of 60 beats per minute and wants an exercise intensity of 60-70 percent, then that person's target heart rate range is between (140 x 0.60) + 60 and (140 x 0.70) + 60 or 144-158 beats per minute.

Because these two methods give different results for target heart rate range, it can be seen that these calculations are only estimates of what your target heart rate should be. Other factors, such as exercise selection and genetics, play roles in determining optimal heart rates, but these methods are useful as guidelines.



Why should I stretch? -- Lisa McNally, class of 2004



In six words: because it's good for you, baby! The main purpose of stretching is to prevent injury; and this is done best by stretching for a solid 15 to 20 minutes before your workout. Stretching is a good way to warm up before an exercise session and a way to make sure that you won't be sidelined due to something that could have been easily prevented.

In addition, out of strength, speed, endurance, and flexibility, flexibility is the only one that has a positive impact on all of the others. By increasing your flexibility, strength can be improved, as longer muscles are more likely to contract. In addition, stretching gives you a greater range of movement during speed workouts. Finally, flexibility may allow your endurance to increase due to the increased range of movement in the joints.

In a nutshell, stretching is very important. Be sure to stretch, even if only for ten minutes, before each and every workout.