Association of physical activity with cardiovascular autonomic modulation and the serum metabolome in healthy men

The associations of the serum metabolome (SM) and cardiovascular autonomic modulation (CAM) are underexplored, especially when considering the connection with regular physical activity. Investigating these associations may help in understanding the systemic effects of regular physical activity. In this exploratory study, the associations between CAM and SM were explored and also compared in physically active and inactive groups. Fifty-one apparently healthy men (37 ± 10 years; 23.6 ± 2.4 kg m^-2) were divided into physically inactive (IG) and active (AG) groups. SM was assessed by using nuclear magnetic resonance spectroscopy and mass spectrometry, and CAM was obtained through resting cardiovascular data. A t-test was used for comparisons between the groups, and a partial correlation was performed to evaluate the associations between CAM and SM. The p-values were adjusted for multiple comparisons using a 0.1 false discovery rate (FDR). Indolelactic acid, lysophosphatidylcholines [LysoPC(20:1) and LysoPC(18:2)], lysophosphatidylethanolamine(18:2), biliverdin, lumirubin, 2-Hydroxyisovalerate, acetate, betaine, and cardiac parasympathetic modulation were higher and glycochenodeoxycholic acid, and L-tyrosine were lower in AG compared to IG (all adjusted p < 0.1). No significant associations were observed between SM and CAM. Regular physical activity was associated with higher cardiac parasympathetic modulation and differences in selected metabolites with no clear associations between SM and CAM.