The research, which followed nearly 8,900 adults over several years, found that both men and women who got married during that time tended to experience a dip in cardiovascular fitness, as measured by treadmill tests.

In contrast, men who got divorced during the study saw a modest increase in their fitness levels…

Still, researchers say the results support the notion that once people are married and, presumably, off the dating market, they tend to let themselves go a bit. But if they remain single or get divorced, they have more incentive to get in shape.