Older adults watch significantly more television than younger people, but they derive much less pleasure and stress relief from it, according to a forthcoming study in the American Journal of Preventive Medicine.

Researchers from the University of California-San Diego were able to eliminate some spurious causes for this link, but they concluded that the relationship between age and amount of TV time could have a few different explanations.

The UCSD scientists surveyed nearly four thousand people between the ages of 15 and 98 on their TV watching habits, their moods, and other non-TV leisure activities. Broken down by age, the data showed that younger adults experience TV much differently from their older counterparts.

The study found that older people are generally happier, but they also watch more TV than younger people do. TV watching was negatively associated with happiness, but also negatively associated with stress—that is, people who watch TV seem to be less happy but also less frazzled.

However, the reduction in stress that comes with increases in TV watching appears to diminish with age. The authors speculate that this is because older adults have less initial stress; therefore, there's less for TV to relieve. So why do older people still watch more TV than anyone else?

The researchers suggest it may be that older people have more free time due to retirement, and TV is an easy way to fill the hours. By this time, they have likely developed TV watching into an addiction of sorts. But the programming during their TV watching hours may be mostly geared towards younger viewers, so older adults may spend much of their TV watching time struggling to find programs that they can enjoy.

The study didn't cover other easy-access leisure activities, so the problem may not be limited to television. Still, if your parents and grandparents are sitting sour-faced in front of MSNBC or FOX News all day, maybe you should do them a favor and introduce them to online bridge. Or a DVR.

American Journal of Preventive Medicine, 2010. DOI not yet assigned.