Effect of Nocturnal and Diurnal Moderate-intensity Swimming Exercise on Increasing Irisin Level of Female Mice (Mus musculus)

Abstract This study aims to compare moderate-intensity swimming exercise in the morning and at night towards the increment of irisin levels in female mice (Mus musculus). This research is a real experiment with the randomized control group post-test-only design. A total of 24 female mice (Mus musculus), aged 3 months old, and weighing 20-40 grams (Lee’s Index Value > 0.3) were randomized into three groups, namely G1 (n = 8, control without intervention), G2 (n = 8, moderate-intensity swimming exercise in the morning), and G3 (n = 8, moderate-intensity swimming exercise at night). Swimming exercises were carried out 3x/w for 4 weeks with an intensity of 6% of body weight and the duration was 70% of maximum swimming time. Irisin levels were measured using the ELISA method. The data analysis techniques used were one-way ANOVA test and Tukey's HSD post-hoc test. The results that were obtained from this experimental study were mean levels of irisin in G1 (1.86 ± 0.06 ng/mL), G2 (2.66 ± 0.12 ng/mL), G3 (3.43 ± 0.35 ng/mL), and (P ≤ 0.001). The results of Tukey's HSD post-hoc test showed that there was a significant difference in the mean post-training irisin levels between G2 and G1 (P ≤ 0.05), G3 and G1 (P ≤ 0.001), and G3 and G2 (P ≤ 0.05). Based on the results of this study, it was concluded that moderate-intensity swimming exercises in the morning and at night were able to increase irisin levels. However, moderate-intensity swimming exercise at night showed a higher effectiveness in increasing irisin levels of female mice (Mus musculus). Keywords: Obesity, Irisin levels, Morning exercise, Night exercise