Objectives: To (1) evaluate preliminary effects of aerobic exercise on progesterone, prostaglandin metabolites and pro-inflammatory cytokines in women with primary dysmenorrhea, (2) assess the feasibility of methodological procedures and obtain preliminary data (effect size) to estimate the sample size for a future randomized controlled trial.
Methods: Twenty women aged 18-29 years were divided into two groups (highintensity aerobic-exercise group and no-exercise control group) in a 1:1 ratio. Women assigned to the exercise group performed high-intensity treadmillbased aerobic exercise for three days a week, at 70-85% of maximum heart rate for 30 minutes for 4 weeks. The control group did not receive trial intervention but provided blood for estimation of plasma variables. Blood plasma levels of progesterone, prostaglandin (PG) metabolites, F2 alpha [KDPGF2α]) and PGE2 (KDPGE2), and tumor necrosis factor-alpha (TNF-α) were measured at 4-weeks post-intervention.
Results: There was an increase in progesterone levels (d=0.36) and decreases in KDPGF2α (d=0.35), KDPGE2 (d= 0.47), and TNF-α (d=0.33) from baseline to week 4 in the exercise group compared with the control group. Concerning feasibility outcomes, 90% of the required number of participants were recruited in 3-4 weeks and adherence to the intervention was 97%.
Conclusion: Study findings suggest that aerobic exercise may be effective for primary dysmenorrhea via its influence on progesterone and inflammatory pain mediators. The study methodology appears to be feasible for conducting a fullscale randomized controlled trial.
Priya Kannan, Kwok-Kuen Cheung, Chan Sheung Chi, Lam King Yan, Law Yee Xi, Ng Sze Ki, Siu Hoi Yan, Sze Chuen Cesar Wong