Select two percentage columns to establish your training parameters--maybe 65% to 80%.

Then, find your age range in the left most column and follow that row to the right until you see the numbers that correspond to your chosen percentages of MaxHR.

Each number equates to your training heartrate objective, in beats per minute divided by four. The beats per minute values have been divided by four to make it easier for you to quickly know whether you're within your target zone. If you are, say, within the 31 to 35 age range your training zone is from 30 to 37 beats per 15 seconds.

So, during exercise, briefly stop and locate your pulse. Once you've found it, begin counting each beat, starting with 0 (zero) as the first beat's number, over 15 seconds. Compare your pulse count with your target range from our chart here, and you'll know right away if you're working out at your desired training level.

These 15 second values are derived from the average of the beats per minute numbers of each age range so the math will not always figure exactly. But, they are all just estimates, anyway. There is also a level of error in counting for only 15 seconds instead of a full 60 seconds. Hell, the whole concept of age-predicted MaxHR for that matter is inexact, too. Nonetheless, this table is close enough for most of us as a quick reference, while working out.

Personally, I don't rely soley on a chart of estimates. I use the karvonen formula to be more exact. But, depending on your goals you can benefit from either.