The author makes a bold claim about the relationship between stair usage and life expectancy, but his evidence does not lend credence to his claim.

One study referenced in the article examined 5,000 households in 13 buildings across five cities. One building had 10 floors (13 steps), and the other had 16 floors (24 steps). Each building had at least 55 apartments. The study found that occupants of the buildings with 13 steps lived an average of 3.1 years longer than did the occupants of the buildings with 24 steps. The author cites this study as evidence that people who live in buildings with elevators are physically less active than those in buildings without elevators. However, it is difficult to accept this conclusion. First of all, the author does not report the number of steps in each building. The buildings with 13 steps may not have 13 steps at all; they may have 14 or 15 steps. The buildings with 24 steps may have 21 or 22 steps. Without that information, it is impossible to determine whether the residents of each building took more steps than their elevator-using counterparts or not.

Second, the study only examined the people who lived in the buildings. It did not examine the people in adjacent buildings or in the surrounding areas who drive or take public transportation to the buildings. Did the people in these buildings walk more, or did they drive more? Did the people in adjacent buildings walk more, or did they drive more? If the people in the adjacent buildings drove more, then the residents of the buildings with 13 steps may have been less active than the people in the buildings with 24 steps. The residents of adjacent buildings may have used their elevators less because elevators are more convenient than stairs.

Third, even if the authors of the study had reported the number of steps in each building, they still would not have identified whether the residents of each building took more steps than the residents of the other building. A building with 13 steps and a building with 24 steps may have the same number of steps but a different distribution of those steps. One building may have many short steps, and the other may have many long steps. The residents of one building may walk more steps in a day than the residents of the other building.

Fourth, the study examined only physical health. It did not examine mental or emotional health. If the people in the buildings with elevators are less mentally or emotionally healthy, then they may have less physical activity and less overall health than the people in the buildings with stairs. Mental and emotional health are just as important in determining a person’s lifespan as physical health. A mentally healthy person may live longer and have a better quality of life than a physically healthy person who suffers from depression or anxiety. If the residents of buildings with elevators are more mentally healthy than the residents of buildings with stairs, then their additional time spent in doctor’s waiting rooms may be due to mental rather than physical health. Fifth, the study found that the people living in buildings with 13 steps had fewer doctors’ visits per year than did the people living in buildings with 24 steps. This conclusion is questionable, however. The residents of buildings with 24 steps may have fewer doctors’ visits per year than do the residents of the buildings with 13 steps simply because the people who live in the 24 step buildings are older and may have more medical issues than do the people in the 13 step buildings. Sixth, the study did not address the difference in health scores between the residents of the buildings with 13 steps and the residents of the buildings with 24 steps. It is possible that the residents of the buildings with 13 steps had scores that were higher than the residents of the buildings with 24 steps, because both sets of residents had fewer medical issues than the people in the adjacent buildings. Finally, the study did not report whether the residents of apartments in the buildings with 13 steps had lower scores on the questionnaires than the residents of apartments in the buildings with 24 steps. It is possible that the residents of the buildings with 13 steps had scores on the questionnaires higher than the residents of apartments in the buildings with 24 steps, because they used the stairs instead of the elevator.

The author offers several plausible explanations for the findings regarding the relationship between stair usage and life expectancy. He begins his discussion with the possibility that people who live in buildings with elevators spend less time in physical activity. However, this claim does not explain why residents of buildings with 13 steps lived longer than did the residents of the adjacent buildings. One potential explanation is that the residents of the buildings with 13 steps exercised more. People who live in places where they have to use stairs instead of an elevator must use the stairs more muscle groups when they walk. That increased activity may yield increased lifespans.

A second plausible explanation for the findings of the study is that people who live on upper floors of buildings are more likely to have health issues. The residents of the buildings with 13 steps may be healthier than the residents of the buildings with 24 steps, but the residents of the adjacent buildings may be sicker because they are physically weaker and more likely to suffer injuries. The residents of the buildings with 24 steps may have more medical issues because the buildings have 24 steps, not 13 steps. If the people in the buildings with 24 steps suffer from impaired mobility, then they may move more slowly and have difficulty climbing the stairs. That inability to climb the stairs may cause them to have decreased lifespans.