​How Shift Workers Can Avoid Sleep Problems

Our body’s circadian rhythm is an internal 24-hour biological clock that regulates and synchronises essential processes such as hormone release, metabolism, and sleep.

This clock signals the brain to release more melatonin, a sleep-inducing hormone, when it detects less sunlight in the environment. That’s why most people naturally feel sleepy at night and alert during the day.

But for shift workers, this cycle is disrupted.

“Shift workers work odd hours and under artificial indoor lighting. During a night shift, the body will adapt to the changed sleep–wake pattern. When this pattern of wakefulness at night is persistent over days and weeks, hormonal adjustments will occur to allow us to adapt to staying awake at night and sleeping in the day,” explains Dr Fong Yuke Tien, Senior Consultant, Occupational Medicine, Singapore General Hospital (SGH), a member of the SingHealth group.

Exposure to light or darkness at specific times can help shift workers adjust their body clock.

According to Associate Professor Joshua Gooley, Principal Investigator of the Chronobiology and Sleep Laboratory, SingHealth Duke-NUS Medical School:

“Normally, the body’s internal clock is synchronised by the daily cycle of sunlight and darkness. This sends out strong sleep signals to ensure that natural sleep occurs in the night. So for the body to adapt to work at night, the internal clock must be reset to match the shift schedule.”

Prof Gooley’s team conducted groundbreaking research in Singapore on how artificial light affects sleep hormones.

Key findings:

• Exposure to room light before bedtime suppressed melatonin production and delayed its onset in 99% of individuals.
• It also shortened melatonin duration by about 90 minutes.
• Exposure to room light during usual sleep hours suppressed melatonin by more than 50% in 85% of trials.

Why this matters:

Melatonin is not just a sleep hormone – it also helps regulate thermoregulation, blood pressure, and glucose control. Chronically exposing yourself to bright indoor lighting in the late evening disrupts melatonin signalling, which may increase risks for poor sleep quality, cardiovascular issues, and metabolic problems.

Research has shown that appropriately timed exposure to light and darkness can help the body adjust to shift work. For example:

• Bright light exposure during the night shift helps the body stay alert.
• Darkness immediately after work (blackout curtains, sleep masks) signals the body to rest.

Limiting electrical lighting before bed – dimming lights in the evening or avoiding screens – may reduce melatonin suppression.

While science continues to uncover more about circadian health, here are practical steps night shift workers can take:

• Maintain a consistent schedule – Go to bed and wake up at the same time daily, even on off-days.
• Create a dark, quiet sleep environment – Use blackout curtains, eye masks, and earplugs.
• Limit caffeine and alcohol before sleep – Both can interfere with rest.
• Nap strategically – Short naps (20–30 minutes) help reduce fatigue without hurting nighttime sleep.
• Use light wisely – Get bright light during work and dim lights before sleep.

Making good choices regarding food and drink can also make a significant difference for shift workers. The key goals are to use nutrition to support energy levels during the working shift (at night) and to promote restful sleep during recovery (the day). This means that shift workers may want to have their main meal just before the beginning of their shift, a moderate meal in the middle and a light meal before they wind down for their sleep, as a large, heavy meal may cause reflux or indigestion and may affect sleep.

Caffeine can help to increase alertness but it is important to use it only at the start of the shift, avoid excessive intake (not more than 2 cups) and make a conscious effort to avoid caffeine at least 4-6 hours before the end of the shift.

Shift work is essential in many industries, but it comes at a cost to health. Shift Work Sleep Disorder (SWSD) can cause fatigue, poor concentration, and increase accident risks.

Prof Gooley’s research, conducted in Singapore, shows that artificial light has a profound effect on melatonin and the body clock. For night shift workers, managing light exposure, sticking to a routine, and practicing good sleep hygiene are crucial steps toward better sleep and long-term health.

Ref: F26