Background: The main aim of the present study is to investigate the independent association objectively measured level of physical activity (PA) and serum concentration of liver aminotransferases (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) among seemingly healthy individuals.

Materials and methods: The current secondary study was conducted in the framework of Khuzestan Comprehensive Health Study, a large population-based multicentric cross-sectional study, conducted between 2016 and 2019 on 18,966 individuals living in Khuzestan province, southwestern Iran. International PA Questionnaire was used for evaluating PA levels, and participants were divided into three groups: low, moderate, and high PA, and ALT and AST were compared between these groups.

Results: The mean ± standard deviation age of participants was 38.65 ± 11.40 years. The majority of participants were female (71%). The mean concentration of ALT in total sample was 18.22 ± 13.06 (male: 23.65 ± 16.26 and female: 15.57 ± 10.06), while the mean concentration of ALT in total sample was 19.61 ± 8.40 (male: 22.44 ± 10.03 and female: 18.23 ± 7.08). A statistically significant inverse correlation was found between AST (r = -0.08, P = 0.02) and ALT (r = -0.038, P < 0.001) with total PA score. The mean concentration of ALT was 19.96 ± 13.63 in people with low PA, 17.62 ± 12.31 with moderate PA, and 18.12 ± 13.47 with high PA (P < 0.001). The mean concentration of AST in total sample was 20.37 ± 8.85 in people with low PA, 19.21 ± 8.83 with moderate PA, and 19.75 ± 8.85 with high PA (P < 0.001). The difference between people in different levels of PA in terms of mean concentration of AST was remained significant (P = 0.003); however, the difference for ALT was not remained significant after adjusting potential confounders.

Conclusion: The current study based on large sample showed that PA had a statistically negative association with the concentration of liver aminotransferases in the seemingly healthy individuals; however, the observed associations were weak. People in the lowest levels of PA had the highest levels of ALT and AST.