In a new study in the journal Health Psychology, people who thought they were less active than their peers had a greater chance of dying younger—even if their actual activity levels were the same.
The research suggests that the health perks of exercise may come not just from the physical movements, but also how people think and feel about them, as well. In other words, people who feel like slackers may not be getting all the benefits they should be from their workouts.
Lead author Octavia Zahrt, a Stanford PhD student in organizational behavior, based her research on a personal experience. “I am from Germany, and back there I felt really good about my activity level,” she says. “I biked to work, and went to the gym maybe once a week.”
When she moved to California, she was suddenly “surrounded by people who exercise all the time,” she says. “Compared to them I felt really inactive, and I developed what I know now was a really negative mindset about my physical activity.”
So Zahrt and her faculty advisor, Alia Crum, PhD, decided to study whether this attitude could have an effect on long-term health. To do so, they analyzed data from 61,141 adults who were surveyed between 1990 and 2006 and followed until 2011.
The adults only answered questions about their activity levels, and some also wore accelerometers to track their real-time activity for a week. In addition, all participants were asked, “Would you say that you are physically more active, less active, or about as active as other persons your age?”
After adjusting their sample to control for factors such as disability, general health status, and demographics, the researchers found that people who believed they were less active than others were 71% more likely to die during the study’s follow-up period—even when activity levels was controlled for, too. In fact, they found that people’s perceptions about their own physical activity levels frequently did not match up with reality.“
It can be easy to compare how much exercise we get with the people around us, as opposed to what’s recommended for everyone,” says Zahrt. “Plus, a lot of people think that exercise has to mean running or going to the gym, and they don’t give themselves credit for all of the other activity they do—cleaning their house, walking to the store, carrying their kids, those sorts of things.”
People who shortchange themselves in this way could be unknowingly sabotaging their health, say the study authors. Meanwhile, those who feel good about their fitness level may benefit as much from their attitude as they do from the physical activity itself.