Correlation between body fat and post-exercise heart rate in healthy men and women

Cardiovascular autonomic reflex tests and serum FGF21 levels in overweight and normal-weight men and women

OBJECTIVE

We evaluated cardiovascular autonomic reflexes and serum fibroblast growth factor 21 (FGF21), a surrogate marker of mitochondrial function, in a cohort of overweight and normal-weight adults (n = 42).

METHODS

Indices of autonomic function were monitored during supine rest, autonomic reflex tests and submaximal clinical exercise test, with heart rate variables and blood pressure measured with an automatic system.

RESULTS

Markers of sympathetic dominance were accentuated in overweight adults, including elevated resting low-frequency to the high-frequency ratio for heart rate variability (203 ± 227 vs. 96 ± 42; p = .01), and handgrip diastolic blood pressure (36 ± 15 mmHg vs. 25 ± 12 mmHg; p = .01). A weak non-significant trend has been found for a negative correlation between blood pressure responses to isometric handgrip test and FGF21 in the overweight group (r = -0.37; p = .09).

CONCLUSIONS

Excess body weight appears to trigger sympathetic overactivity in overweight adults, yet autonomic dysregulation might not be associated with notable changes in serum FGF21.

Sex- and Age-Related Metabolic Characteristics of Serum Free Fatty Acids in Healthy Chinese Adults

Free fatty acids (FFAs), also named nonesterified fatty acids, largely originate from the lipolysis of triacylglycerol stored in adipose tissue. Despite extensive research on sex- and age-dependent effects on lipolysis and lipid mobilization of adipose tissue, the primary differences in the metabolic characteristics of circulating FFAs among normal-weight healthy men and women during aging are still unclear. Here, we measured the concentrations of 45 FFAs in fasting sera of two Chinese community-based studies consisting of 201 metabolically healthy normal-weight adults to ascertain the associations of sex and age with FFA compositions and their upstream and downstream relations. Results showed greater conversions toward n-3 polyunsaturated fatty acids of docosahexaenoic acid and n-6 of docosapentaenoic acid from their precursors in women than in men. Meanwhile, there were significantly positive correlations between the concentrations of a panel of saturated fatty acids with straight chain or branched chain and age in women, whereas no association was found in men. These findings highlight that sex and age should be considered as the potential confounding factors in assessing the risk for metabolic disturbance using FFA biomarkers.