Effect of exercise and dietary intervention on serum metabolomics in men with insomnia symptoms: a 6-month randomized-controlled trial

Abstract

AbstractBackgroundAccumulating evidences have shown that lifestyle interventions such as exercise and diet are associated with improved sleep quality. However, the underlying molecular mechanisms remain unclear. Assessing exercise and diet intervention associated changes in circulating metabolomics profile in people with insomnia symptoms may help to identify molecular biomarkers that may link lifestyle changes to improved sleep outcomes.MethodsThe present study is a part of a 6-month randomized lifestyle intervention on sleep disorder subjects. Seventy-two Finnish men (aged: 51.6 ± 10.1 years; body mass index, BMI: 29.3 ± 3.9 kg/m2) with chronic insomnia symptoms who were assigned into different intervention groups completed this study (exercise n = 24, diet n = 27 and control n = 21). The exercise group was assigned to a progressive aerobic exercise training with intensity of 60 – 75% of estimated maximum heart rate, 3 – 5 times a week. The diet group aimed to reduce their total energy intakes by 300 to 500 kcal per day for the first three months. The control group were advised to maintain their current lifestyle. Sleep was assessed by using a non-contact sleep monitoring devise (Beddit sleep tracker). Blood samples were collected in the morning between 7:00 and 9:00 a.m. after overnight fasting. Gas Chromatography Time-Of-Flight Mass Spectrometry (GC-TOF-MS) method was used to determine the serum metabolites.ResultsTwenty-one metabolites were significantly changed in the exercise group, thirty-three metabolites in the diet group and five metabolites in the control group after intervention, respectively. The differential metabolites after exercise intervention were mainly related to glycerolipids and carbohydrates metabolism, while dietary intervention altered mainly amino acids metabolism and fatty acids metabolism related metabolites. We subsequently assessed the change of those metabolites with the change of sleep parameters and found that decreased alpha-ketoisocaproic acid (r = -0.52, p = 0.026) was correlated with improved sleep efficiency (SE) in the exercise group. Change of 3-hydroxybutric acid (r = -0.47, p = 0.025) and D-glucopyranose (r = -0.54, p = 0.006) correlated negatively with SE in the diet group. On the other hand, oxalic acid (r = 0.49, p = 0.021), D-glucopyranose (r = 0.43, p = 0.048), 4-deoxyerythronic acid (r = 0.60, p = 0.004) and tagatose (r = 0.51, p = 0.016) correlated positively with change of SOL, and 2-keto-isovaleric acid (r = 0.45, p = 0.029) correlated with TST in the diet group.ConclusionIn conclusion, this study identified circulating metabolites that may represent a part of a biological mechanism through which lifestyle interventions are associated with improved sleep quality in people with insomnia.