Caregivers might want to be careful about imposing radically different bed- or wake-up times on residents. Major changes in a person’s long-held sleep patterns increase the risks of death, sleep researchers warn in the current issue of Sleep.

Either adding or taking away significant amounts of sleep could cause problems, they say. Dropping down from six to eight hours of sleep doubles the risk for cardiovascular death, while rising above a typical seven or eight hours of sleep doubles the risk of noncardiovascular death, the British study found.

A regular pattern of six, seven or eight hours of sleep continued over a long time is “protective against premature mortality,” said lead study author Jane E. Ferrie, Ph.D., a senior research fellow in department of epidemiology and public health at University College in London.

More than 17,000 people took part in the study, which included self-administered questionnaires on sleeping and health practices, and basic vital signs monitoring. Past studies have linked sleep’s effects on overall health, but this is the first to connect long-term sleep habits and mortality, Ferrie said.

She said when it came to shortened sleep patterns producing a greater likelihood for heart or circulation problems, it was “fairly obvious what was going on.” Less clear, however, were connections between elongated sleep patterns and the heightened risk of noncardiovascular-related death, she said. “We really don’t know what’s driving that.”