If you’re a female athlete who has ever felt inexplicably off during a training block: sluggish, under-recovered, not quite yourself—there’s a good chance your sleep was part of the story. And there’s an equally good chance you didn’t realize it.
A recent study tracked 12 elite female Gaelic football players across approximately three full menstrual cycles using Oura ring data and daily sleep diaries, uncovering a perception-reality gap in how athletes experience their own sleep.
The disruptions weren’t random; they clustered around two specific phases of the menstrual cycle, the same phases when the body is already managing its highest symptom load.
Twelve elite athletes, three months of data
Researchers recruited 12 Senior Intercounty Ladies Gaelic Football players (average age 24.2 years) and monitored them prospectively for approximately three months, aiming to capture data across three full menstrual cycles.
Sleep is already a known challenge in elite sport. Athletes tend to obtain less sleep than the general population, and demanding training and competition schedules are among the most commonly cited reasons.
For female athletes, the menstrual cycle adds another layer which has been relatively understudied in applied, longitudinal settings.
Participants wore an Oura ring throughout the study to objectively track sleep and physiological variables. They also completed daily sleep diaries, tracked their menstrual cycle and cycle-related symptoms using a smartphone app, and estimated ovulation using urinary testing kits.
Crucially, participants were blinded to their objective sleep data on the Oura app throughout the study: their subjective diary entries reflected genuine perception, not data they’d already seen.
The menstrual cycle was divided into four phases for analysis: Phase 1 (menstruation), Phase 2 (mid-late follicular), Phase 3 (majority of the luteal phase), and Phase 4 (pre-menstrual, defined as the five days before the next menstruation).
This four-phase framework allowed the researchers to pinpoint exactly when sleep disruptions occurred, rather than treating the cycle as a uniform backdrop.
Athletes were sleeping less & waking more than they realized
Participants’ objective sleep, as measured by the Oura ring, was 55 minutes less than their subjective sleep, as reported in their daily diaries.
That’s nearly an hour of sleep that athletes believed they were getting but weren’t. Participants also underestimated the number of times they woke during the night; objective wake events were significantly higher than subjective reports.
They also underestimated the time they spent awake after falling asleep: wake after sleep onset, or WASO (a measure of how fragmented sleep is once it begins), was substantially higher in objective data than participants perceived.
This matters because sleep perception shapes behavior. If an athlete believes she slept well, she’s unlikely to adjust her training load, prioritize recovery, or seek support.
The data suggests that for female athletes, subjective sleep reports alone are not a reliable guide to actual sleep quality, particularly during hormonally active phases of the cycle.
The two highest-symptom windows
Objective sleep quality measures fluctuated across the menstrual cycle, but the disruptions weren’t evenly distributed. They concentrated in Phase 1 and Phase 4.
During Phase 1 (menstruation), sleep efficiency decreased, and both WASO and sleep onset latency (SOL, the time it takes to fall asleep) increased compared to other phases. In plain terms: athletes were taking longer to fall asleep, waking more during the night, and spending a smaller proportion of their time in bed actually asleep.
SOL was also significantly longer in Phase 2 (mid-late follicular) compared to Phase 3, approximately 25% longer, meaning the sleep-onset difficulty didn’t resolve immediately after menstruation ended.
During Phase 4 (pre-menstrual), wake events were significantly higher compared to Phases 2 and 3. This is a distinct pattern from Phase 1: not a global decline in sleep quality, but a specific increase in nighttime waking in the days leading up to menstruation.
Critically, the athletes themselves didn’t report worse sleep during either phase. Their subjective sleep diary entries showed no significant differences across the four phases, even as their objective data told a different story during Phases 1 and 4. The objective disruptions were real; the athletes simply weren’t perceiving them.
It’s not just the hormones: it’s the symptoms
The researchers noted that the prevalence and perceived impact of cycle-related symptoms peaked in Phase 1 and Phase 4, directly coinciding with the objective sleep disruptions observed in the data.
This suggests that sleep disturbances may be closely tied to the experience of symptoms (cramping, bloating, mood changes, physical discomfort) rather than to hormonal phase shifts in isolation.
The pre-menstrual finding is worth highlighting because it’s often underappreciated. Menstruation gets most of the attention when it comes to cycle-related performance and recovery impacts, but the days leading up to it appear to carry their own distinct sleep cost, one that, like Phase 1, goes largely unnoticed by the athletes experiencing it.
This isn’t unique to female athletes. Research on sleep perception more broadly has shown that people are often poor judges of their own sleep quality, particularly when disruptions are fragmented rather than dramatic.
A night with multiple brief wake events may not feel like a bad night’s sleep in the morning, even though the cumulative effect on recovery and cognitive function is real. Sleep doctors themselves use objective data to recalibrate after disrupted nights, a useful reminder that how you feel isn’t always the full picture.
This isn’t just an elite athlete problem
The study focused on elite Gaelic football players, but the implications extend well beyond competitive sport. The physiological mechanisms at play, including hormonal fluctuations across the menstrual cycle, their effects on sleep architecture, and the gap between perceived and actual sleep quality, are not exclusive to elite athletes.
For any active woman who tracks her training, her nutrition, or her recovery, the menstrual cycle is a variable that deserves a place in that picture.
The study’s authors noted that monitoring sleep and menstrual cycle characteristics may help female athletes identify timepoints where sleep may be disrupted and support them in finding mitigation strategies when disruptions occur.
That framing is useful for non-elite athletes and active women too. Knowing that Phases 1 and 4 are higher-risk windows for sleep disruption means those phases can be approached proactively, rather than reactively.
For active women thinking about VO2 max and performance, cycle-aware sleep tracking is one of the most underutilized tools available.
Cycle-aware sleep tracking: what to actually do
The study doesn’t prescribe specific interventions, but its findings point clearly toward a few practical directions.
- Track both sleep and cycle phase: Using a sleep tracker wearable alongside a cycle-tracking app gives you the same dual-data picture the researchers used. The Oura ring was used in this study, but any validated wearable that tracks sleep efficiency and wake events can serve a similar function.
- Adjust expectations during Phases 1 and 4: If you know these phases carry a higher sleep disruption risk, you can plan for it; building in more recovery time, reducing training intensity, or simply not interpreting fatigue during these windows as a fitness problem.
- Don’t rely on how you feel: The 55-minute perception gap is a reminder that subjective sleep reports are unreliable guides to actual sleep quality. If you’re using a wearable, look at the data, especially during menstruation and the days before your period.
- Address symptom burden directly: Since cycle-related symptoms and sleep disruptions peak together in Phases 1 and 4, managing symptoms through nutrition, movement, stress reduction, or targeted supplementation may have downstream benefits for sleep quality during those phases.
The takeaway
The menstrual cycle affects sleep in ways that female athletes aren’t currently detecting on their own, and the gap between what they perceive and what’s actually happening is nearly an hour. The disruptions concentrate in the two phases that already carry the highest symptom load: menstruation and the five days before it. Tracking objective sleep alongside cycle phase, and knowing which windows of the month to watch most closely, is where that gap starts to close.