NEW YORK (Reuters Health) – Among older people getting inpatient rehabilitation after a heart attack, stroke, or injury, the amount of time spent sleeping during the day is a key predictor of how well a person will recover function, new research shows.

These observations are important, the researchers say, because sleep disturbances may be a modifiable predictor of rehabilitation outcomes. In contrast, many other predictors of rehabilitation outcomes such as cognitive function are difficult or impossible to change.

Interventions to improve sleep patterns of older people during rehabilitation, and in particular to reduce daytime sleeping, may promote functional recovery, they say.

“Since functional recovery is the main goal of rehabilitation, we wanted to see if sleep disturbance during the rehabilitation stay would affect the older person’s immediate and long-term functional recovery,” Dr. Cathy A. Alessi, who led the study, told Reuters Health.

To test their theory, Alessi, at the UCLA David Geffen School of Medicine in Los Angeles and her associates studied 245 adults with an average age of 80.6 years who were admitted for inpatient physical or occupational therapy.

The most common reason for admission was an orthopedic condition (42 percent), followed by heart problems (13 percent), stroke or neurological disorder (11 percent), and general weakness (9 percent).

Sleep time was documented with a wrist device worn for 7 consecutive days and nights. On average, subjects slept 55 percent of nighttime hours and 16 percent of daytime hours.

The researchers found that time spent asleep during the day was significantly associated with poorer immediate functional recovery, as was cognitive impairment, and needing to go back to the hospital after admission to the rehab center.

Fewer daytime hours spent asleep was a significant predictor of greater functional recovery at 3 months.

Alessi and colleagues note that a whole host of factors may disrupt patients’ sleep during a hospital stay, such as environmental factors, their medical condition, or sleep disorders.

“We can’t forget that daytime sleepiness is a key symptom of sleep apnea, and providers need to be vigilant to symptoms that suggest sleep apnea, for which specific treatment is available,” she said.

SOURCE: Sleep, September 1, 2008.