Insufficient or shifted sleep
Circadian rhythm
Evidence level : Probable LifestyleMechanism : Hormonal disruption burden
🟡 Several human studies point the same way, with a plausible biological mechanism, but the evidence is not yet conclusive.
- Where it's found
- Nights under 6 hours, night shift work, very irregular schedules.
- Suspected mechanism
- The sleep-wake rhythm paces the secretion of reproductive hormones; its disruption affects the cycle and spermatogenesis.
- Suggested alternative
- Stabilize wake-up time, even on weekends: it is the most effective way to reset the rhythm.
- Source
- Studies on shift work and fertility.
Map your everyday exposures in about ten minutes.
Take the questionnaireRelated factors
Including a factor does not mean it causes infertility: it is simply worth monitoring, depending on its level of evidence.
Content last updated: September 14, 2026