It's no secret the stress of work can keep you up at nights. Now research shows that retirement can spur less fitful sleep, at least for people who are financially stable.

The prevalence of sleep disturbances among 14,714 study participants in France — all of whom had pensions that continued to pay 80 percent of their salaries — fell from 24.2 percent in the last year before retirement to 17.8 percent in the first year after retiring.

Researchers in Finland suggest sleep disturbances may improve after retirement -- for those with secure pensions.

The study, published in the journal Sleep, found a sharp decrease in sleep disturbances in financially secure retirees. However, among the small number retiring early due to illness or disability the risk of sleep disturbances increased 46 percent.