There are times people come and ask me why they are not improving. I typically have two questions: 1. Are you eating a sensible diet? 2. Are you working hard enough?

To work your heart and lungs and get the best results, you actually have to challenge your heart and lungs. So how do you know if you are working hard enough?

There are a couple of ways to figure that out. The easiest way is to go with your perceived exertion. How hard do you feel you are working out? Let’s use the 1-10 scale:

At 1, you are not doing anything and at 10, you are ready to pass out. You typically want to be between a 6 and a 9, depending on your fitness level.

Or we can find your target heart rate zone using the following calculation. Get your calculator or piece of paper. Take 220 and deduct your age, which gives you your maximum heart rate (MHR). You don’t want to exercise at your MHR.

For example, 220 – 58 (age) = 162 MHR. Target heart rate falls between 55/60%-90% of your MHR. Fifty-five percent is best if you have never exercised before and have some health challenges (obesity, heart problems, sometimes even pregnancy). The THR for this 58-year-old with no health problems is the following — take 162 and multiply this number with .60 which is 97.2.

Now take 162 and multiply this with .90, which is 145.8. Typically, your “max” for most people is about 80/85%. The THR for this 58-year-old is between 97 (60%) and 146 (90%) heart beats per minute (BPM). When a 58-year-old is below 97 BPM, they are not working hard enough. Above 146, they are working too hard.

For very fit people, this calculation doesn’t always work as well. For them (and myself), I like to use the Karvonen formula. It also includes your resting heart rate. Still use 220 minus your age and minus your resting heart rate. Use that number and take 60% to 90% and your target heart rate zone is that number. Let’s use the 58-year-old again with a resting heart rate of 50 BPM — 220-58=162-50=112

Sixty percent is 67.2. Add back the resting heart rate which makes the low end 117.2.

Ninety percent using same calculation is 150.8. You can see there is a difference from the “normal” target heart rate. Even that heart rate is very important, it’s easy to go with your perceived exertion while exercising. You don’t have to take your heart rate to know if you are working hard. Now, most watches actually have your heart rate displayed on the watch which is nice. When going by perceived exertion and you can barely keep up with your breath, you are working too hard. Being able to hold a full conversation, you are working too little. Especially those on medication that controls their heart rate, you have to follow your perceived exertion (as lots of medications lower the heart rate). Of course you want to check with your doctor to make sure a new or more challenging exercise program is good for you, and if he or she recommends a certain percentage for your THR. I have never met a doctor who says “don’t exercise,” but you might have some important limitations. So find your target heart for your age, be in tune with your body by “feeling” how hard you are working and keep active. The other day, a retired doctor said “motion is lotion.” I like that. We gotta keep moving for a healthy spirit, mind and body.

Next week, I will talk about another important “exercise” — the “push away” exercise. Push away from the table!

Ester H. Marsh is director of healthy living at the J.F. Hurley Family YMCA.