The study concluded that exercise training induced significant improvement in subjective sleep quality in postmenopausal women, with even a low dose of exercise resulting in greatly reduced odds of having significant sleep disturbance.

The study investigated whether a dose-response relationship existed between exercise and subjective sleep quality in postmenopausal women. This objective represents a post hoc assessment that was not previously considered.

The parallel-group randomized controlled trial consisting of 437 sedentary overweight/obese postmenopausal women and conducted in a clinical exercise physiology laboratory in Dallas, Texas.
Exercise dosages were structured to elicit energy expenditures of 4, 8 or 12 kilocalories per kilogram of body weight per week (KKW), respectively. Analyses were intent to treat.

RESULTS:
Change in the Medical Outcomes Study Sleep Problems Index score at 6 months significantly differed by treatment group (control: -2.09 , 4 KKW: -3.93 (-5.87 to -1.99), 8 KKW: -4.06 (-6.45 to -1.67), 12 KKW: -6.22 (-8.68 to -3.77)), with a significant dose-response trend observed (p=0.02). Exercise training participants had lower odds of having significant sleep disturbance at postintervention compared with control (4 KKW: OR 0.37 , 8 KKW: 0.36 , 12 KKW: 0.34 (0.16 to 0.72)). The magnitude of weight loss did not differ between treatment conditions. Improvements in sleep quality were not related to changes in body weight, resting parasympathetic control or cardiorespiratory fitness.

Kline CE, Sui X, Hall MH, Youngstedt SD, Blair SN, Earnest CP, Church TS. BMJ Open. 2012 Jul 12;2(4). pii: e001044. doi: 10.1136/bmjopen-2012-001044. Print 2012.
Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.