SLEEP PROBLEMS MAY BE CAUSING YOUR WEIGHT GAIN

New Orleans, LA (June 21, 1998) - A study presented at the 12th Annual Meeting of the Associated Professional Sleep Societies in New Orleans, Louisiana, suggests that there may be an important link between weight gain and sleep.

Researchers at the University of Southern Mississippi studied 163 patients with obstructive sleep apnea (OSA), a commonly occurring sleep disorder that involves frequent and long pauses in breathing during sleep that can lead to severely disturbed sleep, to see if decreased REM sleep (a period of intense brain activity and suppressed muscle activity during sleep) is related to obesity in OSA patients.

The study's principal investigator, Jennifer Peszka, noted, "Sleep researchers have known for some time that there is a strong association between OSA and obesity. Approximately 80% of OSA patients weigh 130% or more of their ideal body weight, and substantial weight gain may occur in the year prior to OSA diagnosis. It is likely that weight gain leads to or worsens OSA. It may also be that OSA leads to weight gain and obesity."

Peszka and her colleagues built upon this knowledge by identifying factors that may lead to this vicious cycle. The first factor that they identified was excessive daytime sleepiness and fatigue, which may lead to decreased physical activity and thereby result in weight gain. The second factor the researchers identified was decreased REM sleep. According to Peszka, decreased amounts of REM sleep stage may lead to increased food intake.

The team of researchers from the University of Southern Mississippi specifically examined this second factor. Peszka noted, "The hypothalamus, a part of the brain involved in many motivated behaviors, may be the link between eating and sleeping. Animal studies have shown evidence for this relationship; however, so far there is very little evidence in humans."

To investigate the possibility that decreased REM sleep is related to obesity in sleep apnea patients, researchers examined the relationship between a patient's weight and a common treatment of OSA, nasal continuous positive airway pressure (nCPAP), using 163 patients from Forrest General Hospital's Sleep Disorders Center in Hattiesburg, Mississippi. The researchers' model predicted that patients with the least REM sleep would weigh the most before treatment began, and would show the greatest weight loss with successful nCPAP treatment.

Peszka and her colleagues found evidence to support these predictions. OSA patients with the smallest amount of REM sleep were almost 20 lbs heavier than other patients at the time of diagnosis, and patients with the biggest increase in REM sleep following treatment showed the greatest weight loss at follow-up.

Peszka noted, "This study suggests that decreased REM sleep associated with OSA is a significant contributor to obesity, and that weight loss is possible for some patients using nCPAP." The finding is particularly important since OSA patients can suffer from excessive daytime sleepiness, decreased quality of life, and increased likelihood of heart attack, stroke, hypertension, and other disorders.

Furthermore, this relationship may have broader implications, according to Peszka. A decrease in REM sleep could also lead to weight gain in other circumstances associated with shortened sleep, such as shift work and lifestyle choices.