Objectives: To evaluate the impact of the physical exercise on circulating FGF21 level and the effect of chronic exercise time in normal people.
Methods: A review was conducted according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses using the online databases PubMed, Science Direct, and EBSCO to identify relevant studies published through July 2016. Review Manager was used to estimate the effect of endurance exercise on the change of blood FGF21 concentration. Egger’s test was run to evaluate the funnel plot asymmetry. A smooth scatter diagram was used to determine the impact of exercise time on FGF21 level change.
Results: Overall, five studies with a total of 260 participants indicated a decreased circulating FGF21 concentration after chronic exercise (-87.0 pg/ml, 95% CI: -119.2 to -54.7, p<0.01). Results of age subgroup analysis indicated the decreased FGF21 concentration was only occurred in young people (-86.4 pg/ml, 95% CI: -118.9 to -53.9, p<0.01), not in the middle age and old people (-82.43 pg/ml, 95% CI: -174.57 to -97.1, P=0.08). Ethnic subgroup analysis showed that FGF21 concentration was decreased in both Mongolian (-94.8 pg/ml, 95% CI: -167.2 to -22.5, p=0.01) and none Mongolian (-82.7 pg/ml, 95% CI: -116.2 to -49.3, p<0.00001).
Conclusion: Current evidence demonstrates that chronic exercise significantly decreases circulating FGF21 level, and the reduction degree is increased with the extension of the exercise time.