CrossFit. Bikram. Ultra-marathons. When it comes to the latest exercise trends, nearly all have one thing in common: They take relatively anodyne workouts—lifting weights, yoga, running—and crank the intensity up to 11. If previous generations stuck to the health motto “everything in moderation,” modern America has shifted emphatically toward “go big or go home”—even if some doctors and scientists believe those behaviors approach (and sometimes cross) the line into dangerous territory. So what gives?
The obvious answer is that these programs tend to produce big results in a hurry, says Dr. Juliana Breines, who researches health psychology at Brandeis University. Looked at that way, you could chalk up these workout trends to a Netflix-ified, want-it-now ethos within American culture. But plenty of research suggests the appeal of intense workouts goes far beyond impatience or a desire for quick results.
A new study appearing in the Journal of Consumer Research concludes feeling as though parts of your life have slipped out of your control spurs a craving for effortful activity. “What we’re finding is that when people are feeling a loss of control, they’re particularly likely to go for these high-effort things like very intense workouts because it makes them feel empowered,” says study co-author Dr. Keisha Cutright, an assistant professor of marketing at the University of Pennsylvania.
Along with the demands of work and family, your income, age, and even the economy could be contributing to the sense that you’re losing control of your world, Cutright explains. When it comes to an activity like CrossFit, “You feel like you’re in charge of the desired outcome,” she explains. “You find a certain amount of control over your life, and that feels good.”
Dr. Brock Bastian, a psychologist at the University of Queensland in Australia, has conducted dozens of experiments examining the psychological interconnectedness of pain and pleasure. He says extreme exercise may be a form of “functional” self-punishment—a way of beating yourself up to alleviate some sense of guilt or shame you derive from another part of your life. One of his experiments asked people to recall a time when they’d acted immorally. Following those thoughts, these study participants held their hands in icy water longer than did people who had not been primed to recall a moral transgression. Similarly, “Going on a hard run is perhaps a convenient way to make ourselves feel better after we’ve behaved badly,” Bastian explains. “It makes us feel like the scales of justice have been rebalanced.”
His research also demonstrates that if you feel good about yourself, enduring physical pain can enhance your enjoyment of—and sense of entitlement to—guilty pleasures. Not only that, but inflicting pain on yourself raises your stature in the eyes of others, he adds. Suffering through a grueling endurance race or difficult workout can make you seem tolerant, persistent, and strong in the minds of your friends and colleagues.
Illustration by Peter Oumanski for TIME
On a darker note, there’s also some research that suggests low self-esteem may drive some people to punish themselves though harsh diets or physically demanding exercise, says Breines, the Brandeis health psychologist. “People who are lower in self-esteem may be more likely to choose to suffer based on the belief that they deserve to suffer, and because suffering is more consistent with their negative self-views,” she says, adding that this belief may explain some people’s attraction to extreme diet and exercise regimens.
Of course, there is also the possibility that a healthy appetite for challenge and the physical release of a tough workout is all that's at play for some people. In the end, a complicated mix of some or all of these factors may explain the drive to push workout routines to the limits.
“I've met many people who fashion their daily life, work, and relationships completely around their extremely rigorous exercise routines, and who persist exercising despite injuries,” says Dr. Anna Keski-Rahkonen, who researches public health issues at the University of Helsinki in Finland. But Keski-Rahkonen says it’s difficult to draw a line between a compulsive behavior and something more nefarious. “Currently, it's still quite unclear where normal behaviors end and problematic behaviors begin.”
Consider all of this food for thought the next time you double down on your boot-camp class pack.