Measuring the Impact of Elevation on International Runners

By Kristin Hugo, Caitlin Bird, Ian Evans, Liz Sheeley
BU News Service

Over the years, the Boston Marathon has gone from being a Boston-centric event to an international phenomenon. This year, more than 4,700 international entrants from 80 countries will traverse the 26.2 miles of Massachusetts’ streets in the 120th Boston Marathon. This is a quick look at where they come from.

Running at Altitude

Entrants will be arriving from nations with varying elevations, from Jamaica — which is only an average of 18 meters above sea level, to Chile, at an average of 1,871 meters above sea level. Such variety can have dramatic effects on athletes.

Imagine the Rocky Mountains: beautiful, imposing, capped with snow, looming above the landscape thousands of feet above sea level. If you climbed up for some fresh mountain air, though, you might find it a little hard to breathe. At high altitudes, the concentration of oxygen in the air is less than at lower altitudes. The air pressure is lower, and it’s harder to get oxygen into the lungs. Despite this, athletes have actually been utilizing training at high altitudes in order to improve their performance. However, anecdotal evidence differs from the scientific on whether this is a reliable training method.

Starting at around 2,000 feet above sea level, the human body can start to feel the effects of high altitude, though it is more dramatic the higher one goes. It can become harder to breathe in the thinner air, and there is a possibility one will develop altitude sickness. When the body tries to get more oxygen into the lungs by breathing faster at high altitudes, this can result in the headaches, nausea, fatigue, and sleep disturbance of altitude sickness. Symptoms can vary in severity from mild to severe and may require medical attention, though usually it will dissipate after a few days of acclimatization.

Runners and other endurance athletes might train at a higher altitude because the lack of oxygen also prompts the body to produce the hormone EPO, which increases the amount of red blood cells in the body. Anecdotal evidence claims that this results in an increase in athletic performance, especially if the athlete returns to sea level with the boost. However, scientific studies have found inconsistent or neutral results when testing the effect of altitude.

One reason for the discrepancy might be because of the rigor of statistical significance. Say a scientist has runners do a race, half of whom who have been training at altitude and the other who have not. When she analyzes the results, she has to prove that any differences between the groups could not have happened by chance. If the altitude runners were only a tiny bit faster or slower, then the results might not actually be significant. Yet, running a race a second or two faster might make the difference in an Olympic marathon, so there might be an actual benefit to altitude training.

Elite Runners

Running a marathon takes talent and dedication, but there is a class of runners who go above and beyond. Of the 30,251 people entered the Boston Marathon in 2015, only 36 — 20 men and 16 women — were entered in the elite category.

At 9:32 on the morning of race day, the elite women runners have the honor of being the first heat on the Boston Marathon course. The elite athlete team is recruited and sponsored by John Hancock Financial, and includes past Boston Marathon winners and other athletes from around the world. Ten out of the top 10 men’s times in 2015’s Boston Marathon were in the elite group, and nine out of the top 10 women’s winners were in that group as well.

To qualify to run the Boston Marathon, participants must have scored a certain time in the last year and a half, based on their age and sex. Men ages 18-34, for example, must have run a marathon in the past with a time of three hours and five minutes at most. Women 80 and younger must have run a marathon in under five hours and 25 minutes. The exception to this rule is for people who run with charity groups.

For the elite runners, there is no “qualifying time,” but rather the race sponsor must recruit you. The fastest elite runner’s personal record for a marathon, earned by Lelisa Desisa, was 2:09:17. Desisa went on to win the 2015 Boston Marathon. The slowest elite runner time was 2:29:23, earned by Aleksandra Duliba. Cynthia Limo, from Kenya, debuted in the 2015 Boston Marathon, and had no personal record for the marathon, as she is a half-marathon specialist.