Effect of moderate intensity aerobic training on cardiac autonomic system function and nitric oxide levels in middle-aged males with metabolic syndrome

The sedentary lifestyle in individuals with metabolic syndrome is a main threatening risk for their health. This study aimed to investigate the effects of aerobic exercise with 65% of maximal oxygen consumption on heart rate variability and vascular nitric oxide levels in middle-aged males with metabolic syndrome.

In total, 30 middle-aged men with metabolic syndrome were randomly divided into control and aerobic training groups. At the pretest and posttest, the values ​​of metabolic risk indices, heart rate variability, and nitric oxide were measured in both groups. The aerobic training group performed aerobic exercise for eight weeks at 65% of maximal oxygen consumption. The data were analyzed using the independent and paired t-tests.

According to the results, after comparing the values obtained from the posttest and pretest, there was a significant difference between the training and control groups regarding the fasting blood glucose, triglyceride, metabolic Z score, Standard deviation of NN intervals (SDNN), Square root of the mean squared differences of successive NN intervals (rMSSD), very-low-frequency (VLF), High frequency (HF), and vascular nitric oxide levels. Total cholesterol and low-density lipoprotein levels were significantly different in the aerobic training group, compared to those of the control group and LF as well as LF/HF at the pretest (P=0.01). However, despite slight changes in high lipoprotein and blood pressure levels, there was no significant difference in the aerobic training group, compared to the control group and pre-test.

Regular moderate-intensity aerobic exercise can be used as an appropriate exercise protocol to improve cardiovascular function for males with metabolic syndrome.