Shift work and headache: a new perspective

Shift work and headache: a new perspective 

In many professions, shift and night work are part of daily life. Police officers, hospital workers, firefighters, transport workers: both the public and private sectors depend on people working outside conventional hours. Performing work against the body’s natural rhythm is a challenge for the organism and can entail health risks. What does the latest research reveal about the specific physiological health impacts of shift work, and what effects should those prone to headaches expect?

Shift work is not a marginal phenomenon

According to the German Federal Statistical Office, in 2023 about 15% of employed persons in Germany worked shifts at least occasionally. Of these, 9% performed night work between 11 p.m. and 6 a.m. Shift work is traditionally more of a male domain, and men are still strongly represented, with 28% working evenings, 16% in shifts, and 12% at night. Among women, 23% occasionally worked evenings, 13% did shift work, and 6% worked nights. These figures show that a considerable share of national labor capacity is provided outside the usual working hours.

Humans in the day-night cycle

Our “body clock” regulates the human circadian rhythm. Finely tuned processes in our organism ensure that the alternation of day and night in the environment shapes our activity and governs our sleep. The human circadian rhythm is remarkably inflexible and resists deliberate change. Varying between 23.5 and 25 hours, it is reset to 24 hours each day by sunlight acting as an external time cue.

The body perceives the time of day through the intensity of sunlight. A visual pigment in the retina, known as melanopsin, plays a central role. It registers changes in light intensity with great precision and transmits this information via the optic nerve to the brain. Here, the 24-hour cycle is regulated, and the internal clock is adjusted slightly forward or backward as required. Certain glands in the brain also participate, releasing different hormones over the course of the day that have time-dependent effects on a host of bodily functions and states. Together, these processes generate the human circadian rhythm in a complex interplay and influence, for example, muscle tone, body temperature, hormone levels in the blood, and the sensitivity of sensory organs and nerve pathways. Humans are not unique in this respect: the entire animal kingdom, down to single-celled organisms, responds to the periodicities of its environment.

Shift work disorder: a clinical entity of its own

We described the phenomenon of shift work disorder in detail in this article published in early 2022. Shift work disorder is a multifaceted condition with pronounced somatic and psychological components. The main symptom is disordered sleep, accompanied by an overall reduction in sleep duration compared with day workers. Persistent tiredness can be the result. Some people develop chronic fatigue syndrome, a pathological state of physical exhaustion coupled with impaired cognitive performance.

Additional symptoms include gastrointestinal issues, which over time can lead to inflammatory disease of the digestive tract. Cardiovascular problems are also part of the clinical profile. On the psychological side, depression and anxiety are common, alongside heightened irritability, reduced concentration, and nervousness. The burden is often aggravated by familial and social strain, as shift work markedly affects social participation.

A meta-analysis of 29 studies estimated that more than one in four shift workers (26.5%) are affected by the disorder. And in 2007 the World Health Organization (WHO) revealed another hazard, classifying permanent night work as “probably carcinogenic”.

Shift work and headache in light of recent research</strong

A new review article published in 2024 provides a comprehensive synthesis of current research on the effects of shift work on headaches. It evaluates a series of scientific studies involving more than 400,000 participants altogether. The overall conclusion was a statistically significant increase in the risk of headaches and migraines among shift workers, with night work representing the greatest hazard.

In the case of migraine, studies involving more than 4,500 participants demonstrated that night work substantially heightens the likelihood of attacks. The number of night shifts per month appears particularly decisive in determining how much migraine frequency increases. The authors describe these associations as clearly demonstrable across all occupational groups studied, independent of gender and type of employment. A Danish study found that employees working late shifts were more likely to experience migraine attacks.

Nurses and carers among the worst affected

Several studies converge in showing that employees in the care sector are at increased risk of experiencing headaches as a consequence of shift work. With regard to migraine, considerable gender differences were observed, in fact paralleling those in the general population: female employees were two times more likely to develop migraine headaches than their male colleagues. In other words, women in health care are disproportionately burdened by migraine, regardless of whether they work daytime hours or shifts.

What can be done to lessen the effects?

When it is not possible to avoid shift, night, or weekend work, experts recommend limiting night duty to a maximum of three consecutive shifts. These should rotate forward—for example: early–early–late–late–night. A subsequent rest period of at least 24 hours (ideally, two to three days off work) should follow. Likewise, late shifts should not exceed three in a row, and entire weeks of late shifts should be avoided where possible.

Practical advice for shift and night workers

The latest research underscores the considerable impact of shift work on the burden of headaches. The following strategies offer guidance for structuring everyday routines in order to minimize this impact as much as possible.

The big issue: sleep

For people engaged in shift work, irregular sleep patterns are a major problem. A key recommendation is therefore to keep the sleep–wake cycle as consistent as possible when alternating between early and late shifts. Night shifts pose a greater challenge, but even here certain measures can help.

For example, very bright lighting in the first half of the night (such as daylight lamps) can delay the onset of sleepiness. If feasible, short sleep breaks of about 30 minutes during the shift are beneficial. In the second half of a night shift, as well as during late shifts, caffeine intake should be avoided and lighting reduced as far as possible. Bright sunlight on the way home in the morning is also counterproductive. As darkness fades, the body ceases production of melatonin, the hormone that induces sleep – making it difficult to fall asleep again. Experts therefore recommend wearing sunglasses on the morning commute. Once home, the bedroom should be kept as dark as possible to help you fall asleep quickly.

Nutrition

It’s important for shift workers to eat regularly across changing schedules. Suitable warm main meals include lean meat or fish combined with carbohydrate-rich side dishes such as potatoes, rice, or vegetables. Cold meals may consist of a varied salad and/or wholegrain bread with substantial toppings. Adequate fluid intake is also critical—about two to three liters daily.

During night shifts, two meals are advisable. Because body temperature drops during the night (a signal to the body that it is time to sleep), a warm meal not only provides energy but counteracts this decline, supporting concentration and wakefulness. If a hot dish is not possible, a cold meal accompanied by a warm tea is an alternative. A second meal should be taken about two hours before the end of the shift to sustain concentration and performance. Suitable foods include vegetable soup, unsweetened fruit compote, milk and dairy products, fruit, and light salads. After returning home, a small, not overly heavy breakfast should be eaten before going to bed. A word of caution: be aware that a very rich breakfast or caffeinated drinks may make it harder to fall asleep and stay asleep.

Breaks

Anyone working shifts should be especially mindful about taking short breaks, even though this can be challenging in environments such as hospitals. Whenever possible, breaks should be spent outdoors, as this enhances cerebral blood flow and supports concentration. A particularly valuable technique is Jacobson’s progressive muscle relaxation, a medically tested and easy-to-learn method. By consciously tensing and releasing different muscle groups, the body experiences profound relaxation, increasing the restorative value of even short breaks. Instructions for the exercise can be accessed in the Headache Hurts app or here on the website.

Published: September 2025