*3.2. E*ff*ects of Betaine Supplementation on Lymphocyte Apoptosis and MTP Decline*

Figure 4A presents the results regarding lymphocyte apoptosis after 2 weeks of betaine or placebo supplementation. A two-way repeated ANOVA with treatment and time indicated the interaction between two factors was significant (*p* < 0.05). Lymphocyte apoptosis in participants undergoing 2 weeks of placebo supplementation was significantly higher at the Post-0 and Post-3 time points than at the Pre time point (22.61 ± 13.13%, 24.32 ± 11.49% vs. 6.77 ± 2.34%, respectively, *p* < 0.05). However, lymphocyte apoptosis exhibited no significant differences among the three time points in the betaine trial. Moreover, apoptosis in the betaine trial at Post-0 and Post-3 time points was significantly

lower than that in the placebo trial. Figure 4B presents the results of the phenomenon of MTP decline after 2 weeks of betaine or placebo supplementation. No significant difference was observed in the phenomenon of MTP decline between the trials and time points (*p* > 0.05). The results indicated that twice per day supplementation of 1.25 g of betaine mixed in 300 mL of sports beverage for 2 weeks attenuated lymphocyte apoptosis immediately after EEE but can't benefit on MTP decline.

**Figure 3.** Blood (**A**) betaine and (**B**) choline concentrations before and after 2 weeks of supplementation. \* Significant (*p* < 0.05) difference from before. + Significant (*p* < 0.05) difference from betaine trial.

**Figure 4.** Changes of (**A**) lymphocyte apoptosis and (**B**) mitochondrial transmembrane potential decline in the exhaustive exercise after 2 weeks of betaine supplementation. \* Significant (*p* < 0.05) difference from Pre. + Significant (*p* < 0.05) difference from betaine. Pre, before exercise; Post-0, immediately after exercise; Post-3, 3 h after exercise.

#### *3.3. E*ff*ect of Betaine Supplementation on Oxidative Stress*

Figure 5A,B present the concentrations of TBARS and PC after 2 weeks of betaine or placebo supplementation. A two-way repeated ANOVA with treatment and time indicated there is no interaction between two factors in TBARS and PC. Furthermore, no significant differences were observed in the concentrations of TBARS and PC between the trials and time points (*p* > 0.05). The results showed that two weeks of betaine supplementation had no effects on biomarkers of exercise induced oxidative stress (TBARS and PC).
