Target Heart Rate: Part I

So what is target heart rate? Do a search on “target heart rate” and you’ll get a myriad of web sites to help you understand target heart rate. Some focus on using target heart rate for body building, others for weight loss, some for basic health, others for cardiovascular fitness. In part one I’ll try to drill down to the basics of what target heart rate is and why it’s important for exercise. If you want more information for your specific type of exercise you may want to do a more focused search, using key words of “target heart rate and body building”, or weight loss, or whatever your particular interest is. As always, if you are new to exercise you should consult your health care provider before beginning, start slow and build intensity gradually, and work within your ability and any age and physical limitations you might have.

Target heart rate measures the intensity of one’s workout by how hard your heart is working during exercise. Our hearts work at different levels of intensity depending on our activity level. If we’re sleeping or sitting idle, our heart does not have to work very hard. The measure of our heart rate at rest is called, naturally, resting heart rate (RHR). You can find your resting heart rate by counting your heart rate when you first awake in the morning (count your pulse for 30 seconds and multiply the number by two). Do this for three days, take the average of your results and you’ll have your baseline resting heart rate. How fast our heart beats at rest is determined by age, gender, health conditions, illness, some medications such as beta-blockers, and general level of fitness. Those who exercise regularly at intense levels, such as runners, cyclists, triathletes, and professional athletes generally will have a slow resting heart rate, perhaps as low as 40-60 beats per minute(bpm). This is because a very fit heart is able to beat so strongly that it does not need to beat as often to pump blood through the body. My excellent husband has a resting heart rate between 42-50 bpm and generally sets off alarms any time he’s been on a monitor for a medical procedure. Most people of average age and fitness will have a RHR between 60-80ish. Women tend to run a little higher than men because our hearts are smaller so therefore have to work a little harder.

Next, we need to understand maximum heart rate (MHR). This is the highest level of intensity at which your heart is able to work if needed, such as for running to rescue a child from a burning building. Most of us are only able to work at our maximum heart rate for short bursts of activity, and it is not recommended to try to sustain our maximum heart rate during routine exercise.

Recommendations vary, but for routine exercise, most people will aim for 50-80% of their maximum heart rate. This is the goal, or target heart rate zone (THR).

For most folks, exercise at 50-60% will be brisk, but not extremely challenging. A brisk walk where one is able to carry on a conversation, or a bike ride with kids or just tooling around the neighborhood will get you to 50-60%. At this level, you’ll maintain your level of health and reap the benefits of activity, but probably will not see significant weight loss, improvement in cardiovascular fitness, or increase your fitness to a competitive level. Those who are happy with their current weight and fitness level, or who are unable to exercise harder due to age or physical limitations, will probably want to exercise at 50-60% for 30-60 minutes most days of the week.

If you’re interested in reducing weight and improving your cardiovascular fitness, and are not already exercising vigorously, start by aiming for a THR of 60-70%, and work towards a goal of 60-80%, for 30-60 minutes at least 3-4 days a week, depending on what you hope to achieve. This level of exercise is more challenging – a brisk jog or speed walk, step aerobics, biking at a brisk pace, swimming laps. At this level of exercise you should be able to have a 3-4 word conversation, breath hard but not gasp for breath, and perspire enough to become fairly sweaty by the time you’re done. You might want to consult a trainer, join a training class (i.e. run camp or bike camp) or consult with experienced exercisers to develop an exercise program that will help you achieve this level. There are also plenty of web sites offering training information. For most people it is not necessary to work harder than 80% to achieve aerobic conditioning and weight loss.

For very fit persons interested in advanced conditioning, or for those training for advanced events such as marathons, triathlons, and iron-person competitions, you may need to include some training at a level above 80%. People interested in this kind of training would do well to consult with a trainer or join a training class.

Putting it all together: next we’ll use resting heart rate and maximum heart rate to calculate target heart rate. If you can’t wait until then, do a search on “calculate target heart rate” and you’ll find plenty of advice.