The Average Athlete's Heart Rate During a Marathon

Perhaps you've been running for a while and, like many runners, have become increasingly enchanted with the idea of finishing a marathon. If so, kudos -- but attempting a marathon is more than a matter of just logging through a 26.2-mile run. Understanding your own physiology is essential, and that machine ticking away in your chest is literally at the heart of planning both your training and your race execution. The average athlete's heart rate during a marathon is variable, depending on certain factors.

Everyone who does marathons runs them at a different percentage of his maximum heart rate, which can be estimated using the formula 220 - age, or 206 - (0.88 x age) for women. But it's possible to establish the upper and lower limits of this heart rate. One reference heart rate is that pertaining to your anaerobic threshold, or AT. Since you can run at this heart rate -- which is about 80 to 90 percent of max, depending on your fitness level -- for about an hour, your marathon heart rate is necessarily slower than this, given that the world record as of 2013 was more than two hours. On the other hand, you're not running aerobically unless you're above about 70 percent of max, according to the website Brian Mac Sports Coach.

In 2012, about 487,000 people finished marathons in the United States. Fifty-eight percent were men; nearly half -- 46 percent -- were older than 40. The median age of women finishers was 35 and that of men, 40. The median time of male finishers was four hours, 17 minutes, while that of women was four hours, 42 minutes -- a difference of just less than 10 percent. This is similar to the difference between the men's and women's world records as of 2012 -- two hours, three minutes for men and two hours, 15 minutes for women. Both the average age and median time has been trending upward for both sexes since 1980, when 90 percent of finishers were men, according to Running USA.

Two-time Olympic Marathoner and exercise physiologist Pete Pfitzinger suggests that ideal marathon training spans a range of heart-rate zones, from the easiest aerobic running to the most intense anaerobic running. He says that anaerobic threshold, or tempo, runs -- done at 80 to 90 percent of max -- of 20 to 40 minutes are critical for improving the anaerobic threshold, a key consideration in marathon fitness. Long runs done 10- to 20-percent slower than goal marathon pace are indispensable. VO2 max intervals done at 94 to 98 percent of max develop anaerobic power. Finally, marathon pace runs offer the ultimate in specific preparation.

Given that the lower end of aerobic effort corresponds to about 70 percent of maximum heart rate and that the lower end of anaerobic-threshold running corresponds to about 80 percent of max, the marathon heart rate for a typical runner must necessarily fall between these figures. Furthermore, if the median age of a marathon participant is about 40, then the average maximum heart rate of a U.S. marathoner is about 180. Seventy percent of 180 is 126, while 80 percent is 144. Therefore, the heart rate of a mid-pack runner during a marathon is near the middle of the range -- between 126 and 144, or 135 beats per minute.