Period pain, known medically as primary dysmenorrhea, shares some overlapping biology with PMDD — including hormone fluctuations, inflammation, and premenstrual mood symptoms. This study explored whether high-intensity interval training (HIIT) on a spinning bike, a daily probiotic supplement, or both together could help reduce menstrual pain and premenstrual symptoms over 10 weeks.
Sixty-five women with and without period pain were divided into five groups. Those who completed the HIIT program — short, intense cycling sprints twice a week — experienced meaningful reductions in menstrual pain (roughly a 30-point drop on a 100-point pain scale), less menstrual distress, and fewer premenstrual symptoms like irritability, anxiety, depression, and fatigue. Blood tests showed that exercise lowered inflammation markers and shifted several hormones (including progesterone and cortisol) closer to levels seen in the pain-free group. Exercise also improved cardiovascular fitness and explosive strength.
The probiotic supplement — a three-strain mixture taken daily — showed more modest benefits. It helped reduce some premenstrual emotional symptoms like anger, depression, and fatigue, but did not significantly reduce pain intensity or most inflammatory and hormone markers. It also did not improve physical fitness.
While this research focused on period pain rather than PMDD, the findings about exercise reducing premenstrual mood symptoms and modulating inflammation and hormones are relevant. The results suggest that regular intense exercise could be a meaningful complementary approach for managing menstrual-related discomfort. Probiotics may offer some emotional symptom relief, though evidence here was limited. The study was relatively small, with only about 14-15 people per group, so these findings would benefit from confirmation in larger trials.
Key findings
- HIIT significantly reduced VAS pain scores by approximately 30 mm compared to the dysmenorrhea-only group (from ~7.5 to ~4.3-4.4 in exercise groups vs. 7.5 remaining in Dysmen group)
- HIIT groups (DysmenEx and DysmenExPro) showed significant decreases in inflammatory markers hsCRP and prostaglandins (PGE2 and PGF2α), and significant modulation of hormones (increased progesterone and cortisol, decreased estradiol and prolactin)
- Probiotics alone (DysmenPro) significantly reduced premenstrual syndrome total scores within group (39.3 to 33.7, p<0.05) and improved symptoms of anger, depression, tearfulness, and fatigue, but had no significant effect on pain intensity, prostaglandins, or most hormone levels
- HIIT significantly improved cardiovascular endurance (3-min step test) and explosive power (standing long jump and triple jump) in exercise groups, while probiotics had no significant effect on physical fitness
- Menstrual distress (MDQ) and pain severity (SF-MPQ) were significantly positively correlated with prostaglandins, hsCRP, and prolactin (r=0.278-0.771, p<0.05) and negatively correlated with cortisol and progesterone (r=-0.320 to -0.522, p<0.05)
- Probiotics alone significantly decreased estradiol levels within the DysmenPro group but did not significantly affect hsCRP, cortisol, progesterone, or prolactin
Methods, briefly
Double-blind, randomized controlled trial with N=65 female participants (aged 18-40) who completed the study: control/non-PD (n=10), dysmenorrhea with placebo (Dysmen, n=14), dysmenorrhea with probiotics (DysmenPro, n=15), dysmenorrhea with HIIT and placebo (DysmenEx, n=15), and dysmenorrhea with HIIT and probiotics (DysmenExPro, n=14). The 10-week intervention included HIIT spinning bike sessions (2x/week, 15-20 min of 15 sprints of 20s with 40s recovery at >85% max HR) and daily probiotic capsules (1.5×10^10 CFU of 3-strain mixture). Pre- and post-intervention assessments included PSST, MDQ, SF-MPQ questionnaires, physical fitness tests, blood biochemical markers, hormones, and prostaglandin levels. Blood collected ~3 days before menstruation. Registered at ClinicalTrials.gov (NCT05326217).
Limitations to keep in mind
- Small sample size per group (n=10-15), limiting statistical power and generalizability
- Participants were female university students, which may not generalize to broader populations
- No analysis of gut microbiota or metabolites to elucidate mechanistic pathways of probiotic effects
- Single time-point blood sampling (~3 days before menstruation) does not capture prostaglandin and hormone fluctuations across the full menstrual cycle
- 10-week intervention duration may be insufficient to observe full probiotic effects
- Control group was non-dysmenorrhea participants rather than PD participants receiving no intervention
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