The effect of physical exercise interventions on insomnia: A systematic review and meta-analysis

6-10 % of Europeans suffer from chronic insomnia. They have a higher risk to develop mental and cardiovascular diseases. Treatment of insomnia primarily recommended by the European guideline is cognitive behavioral therapy for insomnia (CBT-I). A quarter of patients treated with CBT-I do not respond sufficiently. The objective of this paper is to examine the influence of exercise interventions on insomnia by conducting a systematic review and meta-analysis. A database search was conducted, including randomized controlled trials (RCT) in which participants had received a diagnosis of insomnia or experienced symptoms thereof. Exercise interventions had to meet the definition of the World Health Organization (WHO), and their implementation was reported according to the FITT (Frequency, Intensity, Time and Type) principle. There was an inactive control and subjective or objective sleep parameters as outcomes. Nineteen studies were included. Results showed a significant improvement for objective (standardized mean difference, SMD = 0.37; confidence interval, CI = [0.17; 0.57]) as well as subjective (SMD = 0.90; CI = [0.61; 1.19]) sleep parameters. Meta-regression showed that the effect increased with intensity of intervention, mean age of participants and percentage of females, but showed high heterogeneity across studies. These results suggest great potential for treating insomnia. Conducting larger trials is advisable to provide precise recommendations.