A growing body of research suggests that splitting sleep into two planned sessions may help night shift workers recover better when uninterrupted daytime sleep is difficult.
- Split sleep may help night shift workers get more total sleep and stay alert
- Studies suggest biphasic sleep could reduce fatigue and support cognitive performance
- Experts say stronger evidence is still needed before it becomes a standard recommendation
Splitting sleep into two planned periods may help night shift workers get more rest, stay alert, and possibly reduce some long-term health risks, according to a new review published in Sleep Medicine Reviews (1✔ ✔Trusted Source
Which individually-directed nonâ€pharmacological interventions are effective at improving sleep outcomes in shift workers? A systematic review of systematic reviews
).
Researchers say biphasic sleep could be a practical option for people who struggle to get one long block of daytime sleep.
Night shift workers are usually advised to sleep in one uninterrupted stretch after work. However, daylight, family responsibilities, and other daytime interruptions often make this difficult.
The review suggests that dividing sleep into two planned sessions may help increase total sleep time, reduce fatigue, and support cognitive performance.
However, researchers caution that the evidence is still limited, and larger studies are needed before biphasic sleep can be widely recommended.
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Can Biphasic Sleep Improve Alertness and Cognitive Performance?
Although sleeping in one uninterrupted block has long been considered the ideal approach for adults, researchers are beginning to question whether this recommendation works equally well for everyone—especially people who regularly work at night.
The latest review in Sleep Medicine Reviews suggests that biphasic sleep, or dividing sleep into two separate periods between work shifts, may help some night shift workers recover more sleep while adapting better to irregular schedules.
Rather than replacing total sleep, the strategy aims to distribute it more effectively across the day when continuous daytime sleep is difficult to achieve.
Many night shift workers already follow this pattern naturally. They may sleep for a few hours after returning home and then sleep again before starting the next shift. Researchers say this approach may fit better around family responsibilities and daytime commitments than trying to obtain one long block of uninterrupted sleep.
Recent studies have explored biphasic sleep from different perspectives. Together, they suggest that split sleep may improve recovery for some night shift workers, although larger studies are still needed to confirm its long-term benefits.
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Evidence from Recent Studies on Biphasic Sleep
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Source |
Key Findings |
|
Sleep Medicine Reviews |
Biphasic sleep may increase total sleep time, improve alertness during night shifts, reduce fatigue, and support cognitive performance. |
|
Sleep Medicine (2✔ ✔Trusted Source Biphasic sleep and human health: A theoretical paradigm for personalized sleep ) |
Split sleep may be a natural and flexible sleep pattern. Researchers suggest sleep schedules should be personalized based on biological rhythms, chronotype, and daily responsibilities. |
|
BMJ Open (3✔ ✔Trusted Source Biphasic sleep in shift workers and its related outcomes: a scoping review protocol ) |
Current evidence is still limited. Researchers are conducting a comprehensive review to determine which shift workers benefit most from biphasic sleep and its effects on health and work performance. |
After reviewing the available evidence, researchers agree on one important point: biphasic sleep should be viewed as a promising strategy rather than a proven solution.
While early findings are encouraging, larger clinical studies are needed to identify who benefits the most and whether split sleep improves long-term health outcomes.
Until then, experts continue to recommend prioritizing adequate total sleep, whether it is achieved in one uninterrupted block or two planned sleep sessions.
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Why Does Night Shift Work Increase Health Risks?
Night shifts force the body to stay awake when it is naturally programmed to sleep. This mismatch disrupts the circadian rhythm, the body’s internal clock that regulates sleep, hormone release, metabolism, body temperature, and many other essential functions.
Exposure to bright light at night and trying to sleep during the day can reduce both the quantity and quality of sleep. Over time, this creates a growing sleep debt, leaving many workers feeling tired even after spending several hours in bed.
Recent evidence suggests that the effects may extend far beyond fatigue. A recent systematic review and dose-response meta-analysis involving 23 cohort studies found that night shift work increased the overall risk of cardiovascular disease by 13% and cardiovascular-related death by 27% (4✔ ✔Trusted Source
Association between night shift work and cardiovascular disease: a systematic review and dose-response meta-analysis
The researchers also observed that every additional five years of night shift work increased the risk of developing cardiovascular disease by 7%, highlighting how long-term exposure can gradually affect heart health.
What Is the Best Sleep Routine for Night Shift Workers?
While biphasic sleep may benefit some night shift workers, experts agree that getting enough quality sleep is more important than whether it occurs in one block or two. Adults should aim for 7 to 9 hours of sleep every 24 hours and follow a sleep routine that best fits their work schedule.
Several practical habits can help improve sleep quality and reduce fatigue among night shift workers (5✔ ✔Trusted Source
The Best Sleep Schedule for Night Shift Workers
Healthy Sleep Habits for Night Shift Workers
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Recommendation |
Why It Matters |
|
Get 7–9 hours of total sleep daily |
Helps reduce sleep debt and supports physical and mental health. |
|
Keep a regular sleep schedule |
Helps the body adapt better to night shifts, especially for permanent shift workers. |
|
Try biphasic sleep if needed |
Two planned sleep sessions may be easier than one long daytime sleep. |
|
Sleep in a dark, cool and quiet room |
Reduces daytime disturbances and improves sleep quality. |
|
Use bright light during work and avoid sunlight after shifts |
Supports alertness at work and helps the body prepare for daytime sleep. |
|
Limit caffeine to the early part of the shift |
Reduces the risk of delayed sleep after work. |
|
Take short planned naps when possible |
May improve alertness and reduce fatigue before or during a shift. |
|
Seek medical advice for persistent sleep problems |
Can help identify conditions such as Shift Work Sleep Disorder. |
Although these strategies show promise, researchers caution that no single approach works for everyone.
However, the overall quality of evidence remains limited, highlighting the need for larger clinical studies before any one strategy can be recommended as the standard approach for all shift workers.
How Does Night Shift Work Affect Healthcare Workers in India?
An Indian study, the SNORE (Sleep Deprivation among Night Shift Health Staff on Rotation Evaluation) study, highlights how night shifts can affect the cognitive health of healthcare professionals (6✔ ✔Trusted Source
Cognitive function and shift work among healthcare professionals in India: Findings from the SNORE study
).
Conducted in a tertiary care hospital in Tamil Nadu, the study assessed 293 doctors, nurses, and paramedical staff working rotational night shifts.
Key Findings from the SNORE Study
- 5% of healthcare workers showed cognitive impairment during night shifts.
- Nurses were the most affected, with 2% showing impaired cognitive performance.
- Cognitive impairment dropped to4% during day shifts.
- Sleeping less than 7 hours significantly increased the risk of poor cognitive performance.
- Attention, memory, concentration, judgement, and decision-making declined during night shifts.
The researchers say these findings highlight the need for better sleep strategies and healthier working conditions for night shift employees.
Although the study did not evaluate biphasic sleep, it supports the growing search for practical ways to improve sleep, reduce fatigue, and protect both worker well-being and patient safety.
Frequently Asked Questions
Q: What is biphasic sleep?
A: Biphasic sleep is a sleep pattern in which a person sleeps in two separate periods within a 24-hour day instead of one long continuous sleep.
Q: Is biphasic sleep better for night shift workers?
A: Current research suggests it may help some night shift workers get more total sleep, improve alertness, and reduce fatigue, but stronger evidence is still needed.
Q: How many hours should night shift workers sleep?
A: Most adults should aim for 7 to 9 hours of total sleep every 24 hours, regardless of whether the sleep occurs in one block or two sessions.
Q: Why are night shifts linked to health problems?
A: Night shifts disrupt the body’s circadian rhythm, increasing the risk of chronic sleep loss, obesity, diabetes, heart disease, depression, and reduced cognitive performance.
Q: Can taking naps help during night shifts?
A: Planned naps before or during a night shift may improve alertness and reduce fatigue, especially when combined with other healthy sleep habits.
Q: What are the best ways to improve daytime sleep after a night shift?
A: Experts recommend sleeping in a dark, cool, and quiet room, maintaining a regular sleep schedule, limiting caffeine before bedtime, and reducing exposure to bright morning light after work.
Q: Does biphasic sleep replace healthy sleep habits?
A: No. Researchers emphasize that biphasic sleep is only a potential strategy. Getting enough total sleep and maintaining good sleep hygiene remain the most important priorities.
References:
- Which individually-directed non‐pharmacological interventions are effective at improving sleep outcomes in shift workers? A systematic review of systematic reviews – (https://www.sciencedirect.com/science/article/pii/S1087079225000632)
- Biphasic sleep and human health: A theoretical paradigm for personalized sleep – (https://www.sciencedirect.com/science/article/pii/S1389945725004186)
- Biphasic sleep in shift workers and its related outcomes: a scoping review protocol – (https://pmc.ncbi.nlm.nih.gov/articles/PMC13007107/)
- Association between night shift work and cardiovascular disease: a systematic review and dose-response meta-analysis – (https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2025.1668848/full)
- The Best Sleep Schedule for Night Shift Workers – (https://www.sleepfoundation.org/circadian-rhythm/best-sleep-schedule-night-shift-workers)
- Cognitive function and shift work among healthcare professionals in India: Findings from the SNORE study – (https://link.springer.com/article/10.1186/s12982-025-00742-z)
Source-Medindia