That "Can't Wind Down" Feeling After A Long Shift? Science May Explain Why
If you've ever felt completely "off" after a long day at work (i.e.,wired but exhausted, unable to wind down) there may be a biological explanation. New research suggests that working extended hours doesn't just leave you mentally drained; it may actually disrupt your body's natural stress hormone patterns.
What the study found
A study published in 20261 examined how single versus double shifts affect cortisol levels in 52 female nurses working rotating schedules. Researchers collected saliva samples before, after, and at midnight during both shift types.
The results showed that nurses working double shifts had significantly higher cortisol levels overall compared to those working single shifts. Most notably, cortisol levels at midnight were nearly two-fold higher in double-shift workers—a time when cortisol should naturally be at its lowest point.
Why your cortisol rhythm matters
Cortisol follows a predictable daily pattern called the diurnal rhythm. Levels peak in the morning to help you wake up and feel alert, then gradually decline throughout the day, reaching their lowest point around midnight to support restful sleep.
When this rhythm gets disrupted (whether from long work hours, irregular schedules, or chronic stress) the consequences can ripple through your entire system. A 2026 systematic review2 of shift work and cortisol found that night shifts in particular are linked to cortisol imbalance and circadian misalignment among nurses.
Additional research from 20233 found that nurses working 12-hour shifts had higher cortisol levels and desynchronized circadian rhythms compared to those on 8-hour schedules. This hormonal disruption may help explain why extended work hours are associated with poor sleep quality, fatigue, and burnout.
What this means for you
While this study focused specifically on nurses, the underlying biology applies broadly. If your job regularly demands long hours or irregular schedules (anything outside of a traditional 9 to 5 really), your cortisol rhythm may be taking a hit.
Signs of cortisol disruption can include difficulty falling asleep after work, feeling wired at night, morning grogginess, or persistent fatigue that sleep doesn't fix.
How to support your stress response when your schedule works against you
You may not be able to control your work hours, but you can take steps to help your body recover and regulate cortisol more effectively:
- Create a wind-down ritual after long shifts: Even 10-15 minutes of intentional decompression (dim lighting, slow breathing, a warm shower) can signal to your nervous system that it's time to shift out of "work mode." Winding down with a magnesium mocktail (like this) can also help.
- Prioritize sleep consistency on your days off: While you can't always control when you sleep during work stretches, keeping a regular sleep-wake schedule on off days helps anchor your circadian rhythm.
- Move your body, but time it wisely: Gentle movement like walking or stretching can help lower cortisol, but intense exercise close to bedtime may keep levels elevated. Aim for calming movement after long shifts.
- Practice micro-recovery throughout your shift: Brief moments of slow, deep breathing (even 60 seconds) can help activate your parasympathetic nervous system and prevent cortisol from staying chronically elevated.
- Protect your mornings when possible: Exposure to natural light in the morning helps reinforce your cortisol awakening response, supporting a healthier daily rhythm even after disrupted nights.
Important limitations to note
This was a small study of 52 female nurses—a specific population with unique work demands. The research measured short-term cortisol changes, not long-term health outcomes. More research is needed to understand how these patterns play out across different professions, genders, and over extended periods.
That said, the findings align with a growing body of evidence linking shift work and long hours to hormonal disruption.
The takeaway
Optimizing your sleep on a schedule that isn't optimized for your biology can be challenging. So, focus on what you can control: how you wind down, how you protect your sleep on off days, and how you build micro-moments of recovery into demanding stretches.
