Finding Your Maximum Heart Rate
Now you've bought your heart monitor. How do you make sure you are using it so that it becomes a relevant training tool and is not tossed in a drawer to be forgotten? Trying to determine your maximum heart rate (MHR) can sometimes be confusing and exasperating. Ask runners such as MCRRC Coach Jan Tripp. When she first strapped on a monitor, her heart rate on a moderate run was well above her predicted MHR. Did this mean she was risking life and limb every time she went for a run? No, it simply meant that Jan was one of the roughly 10-15 percent of runners whose MHR does not meet predicted values.
An April 24th article in the New York Times reported that researchers have concluded the traditional formula for calculating MHR is not always accurate. This is not earth-shattering news, as I have written about MHR in past Rundown columns in which I shared my experiences working with Coach Roy Benson.
So, how do you go about trying to estimate your MHR to find out whether you are someone like Jan Tripp? You can have a treadmill stress test from a cardiologist or fitness center--but there are two difficulties with this. First, cardiologists are very expensive and are only interested in determining whether you have a healthy heart. They frequently stop the treadmill before you reach MHR because they have satisfied themselves that you have a healthy heart. Also, it takes a very skillful operator to get you to your MHR because your heart, legs, and lungs all must reach exhaustion at the same time. Otherwise, you may experience lactic acid build-up in your legs or go into oxygen debt before you reach your MHR. That once happened to me, whereupon the fitness center tester tried to tell me my MHR was 165 when I knew it to be about 180 because I had seen my monitor reach the high 170s.
A second approach involves running all-out 800s back-to-back. The thinking is that by the end of the second 800 you will be close to your MHR. This is a brutal way of finding your MHR and it is also quite difficult, especially if you're doing it by yourself. Moreover, if you go out too hard you will experience lactic acid build-up or oxygen debt before reaching your maximum. Many experienced runners, however, have used this method to come up with a pretty accurate MHR.
The Roy Benson Low-Effort MHR Test
I learned a much easier, less stressful way to come up with your MHR from Coach Roy Benson. All you need to know is your resting heart rate (RHR) and current 10K-race time (presuming an all-out effort). Start by assuming your MHR is 205 minus half of your age. Then use the following formula to determine your 60-65 percent effort:
[(MHR-RHR) x .60] + RHR = 60% effort
[(MHR-RHR) x .65] + RHR = 65% effort
Go to a track and run a mile keeping your heart rate between 60 and 65 percent. Record your mile time and then look at the pace chart. If the mile time lines up with your 10K race time, then you have determined your approximate MHR. If, however, your mile time is slower, you need to adjust your MHR upward by 12 beats, recalculate 60-65 percent, and try it again. If your mile time is faster, adjust your MHR downward and recalculate 60-65 percent. By using this trial-and-error approach, you should be able to zero in on your MHR in two or three tries.
Let me give a practical example. Assume a resting pulse of 45 and a 10K time of 46:00 minutes for a 40-year-old runner. The predicted MHR is 185, and 60 percent effort is [(185-45) x .60) + 45] = 129. Likewise, 65 percent effort is 136. If the runner does a mile keeping her heart rate between 129 and 136 in the vicinity of 9:38, then her MHR is roughly 185. If, however, it takes 10:20 to run a mile, she should use an MHR of 197, recalculate 60-65 percent of (135-143) and run another mile. If the mile time is still not in the range of 9:38, then make another adjustment in MHR (upward or downward depending upon the time) until the mile time is in the 9:38 range.
| Current 10K Time | 60-65% Effort |
|---|---|
| 33:00 (5:19/mi) | 7:04 |
| 34:00 (5:20/mi) | 7:16 |
| 35:00 (5:39/mi) | 7:28 |
| 36:00 (5:49/mi) | 7:40 |
| 37:00 (5:58/mi) | 7:52 |
| 38:00 (6:08/mi) | 8:04 |
| 39:00 (6:17/mi) | 8:16 |
| 40:00 (6:27/mi) | 8:28 |
| 41:00 (6:37/mi) | 8:40 |
| 42:00 (6:46/mi) | 8:52 |
| 43:00 (6:56/mi) | 9:03 |
| 44:00 (7:06/mi) | 9:15 |
| 45:00 (7:16/mi) | 9:27 |
| 46:00 (7:25/mi) | 9:38 |
| 47:00 (7:35/mi) | 9:50 |
| 48:00 (7:44/mi) | 10:01 |
| 49:00 (7:54/mi) | 10:13 |
| 50:00 (8:04/mi) | 10:24 |
| 51:00 (8:14/mi) | 10:35 |
| 52:00 (8:23/mi) | 10:46 |
| 53:00 (8:33/mi) | 10:58 |
| 54:00 (8:43/mi) | 11:09 |
| 55:00 (8:52/mi) | 11:20 |
| 56:00 (9:02/mi) | 11:31 |
| 57:00 (9:11/mi) | 11:42 |
| 58:00 (9:21/mi) | 11:52 |
| 59:00 (9:31/mi) | 12:03 |
| 60:00 (9:41/mi) | 12:14 |
Coach West is a licensed coach, affiliated with MCRRC, and available to coach motivated adult runners. A portion of his coaching fees for MCRRC members is returned to MCRRC. For further information about personal coaching opportunities, contact Coach West at kirtwest@comcast.net.
