Your internal clock: sleep-wake rhythm and headaches

Humans are hard-wired to follow a routine. Your natural 24-hour cycle (circadian rhythm) governs many of the physiological processes in your body, including brain activity, blood pressure, hormones and body temperature. Your sleep-wake cycle is part of that finely tuned system.

Studies in shift workers highlight the negative health consequences of disrupting your natural sleep-wake cycle. Shift work typically involves irregular working hours that overlap with your natural sleep period (night shifts). Rotating shift schedules (switching back and forth between a day and a night schedule) are even worse because they constantly mess with your rhythm. A lot of research has been done in this area, mainly in health workers. Shift work is particularly common in the healthcare sector, not to mention the extraordinary pressures that come with the job – even in non-pandemic times.

What the science says: shift work and headaches

Shift work poses fundamental health risks. Some of the evidence comes from a study by Appel et al. (2018) in more than 5000 medical and non-medical workers in various parts of Denmark. In female participants, shift work was associated with an increased risk of migraine attacks, while male subjects struggled more with other types of headaches.

A growing body of research indicates that, in most cases, headaches and migraines associated with shift work are not isolated phenomena but part of a larger clinical entity called “shift work disorder”. The theory is that shift work causes symptoms including mood swings, problems falling asleep and staying asleep, depression, anxiety states and an increased risk of migraine or headache attacks. These individual components can reinforce or even trigger each other.

A 2018 study by a research group based in Oslo, Norway, confirms the connection. Analysis of the effects of shift work disorder in nurses found higher rates of acute and chronic tension headache and higher incidences of migraine attacks in study participants. The authors conclude that these health issues are not a direct result of shift work but part of the larger phenomenon of shift work disorder. Seen in this light, headache is a symptomatic manifestation of shift work disorder.

Messing with your rhythm makes you sick

Scientists are still largely in the dark about the mechanisms underlying the health effects of shift work. A review by Hittle and Gillespie (2018) sheds a little light on the topic. The authors address the confirmed theory that people have different chronotypes. A person’s chronotype is their natural inclination to be a night owl or an early bird, or something in between. Chronotype varies from person to person. The study suggests that certain chronotypes can make a person more or less susceptible to medical conditions linked to shift work, including heart disease, stroke, diabetes, eating disorders and various forms of cancer. The research indicates that the problems happen when patients’ circadian rhythm is disrupted, resulting in chronic malfunction of key physiological processes and increasing the risk of developing full-blown disease sooner or later. Recent evidence suggests that shift work hits the immune system hard. Researchers are working to identify the underlying processes and to explain why a mismatch between your sleep-wake cycle and your work schedule interferes with vital body functions.

Bottom line: your head reacts

To sum up: shift workers have higher rates of headache disorders than the general population. And female workers are more likely than men to develop chronic headaches. The main takeaway is this: a work and life schedule that goes against your natural (individual) sleep-wake cycle is bad for your health.

What are the implications for university life?

Partying is part of student life. That’s no big surprise. So is pulling all-nighters to study for big exams. But for students living with headaches and migraines, it still means an added risk. Toss a high workload and mental pressure into the mix – during exam period, for instance – and your risk of headaches and migraine attacks increases even more. What’s important is to make sure these phases are the exception, not the rule. As far as exam pressure goes, it helps to draw up a realistic schedule that you can complete bit by bit throughout the semester without spending nights at your desk. If you spread out your workload across the whole semester, the immediate pre-exam period will be much more relaxed and you won’t find yourself having to stay up all night. If you have a ‘side hustle’ (part-time club or bar work, for instance) that keeps you up late at night, try to work regular shifts to save your body from having to readjust all the time. Here’s a useful tip for (partying or working) night owls: Try to get your normal amount of sleep all the same (seven hours is a good rule of thumb). Migraineurs, remember: grab a bedtime snack (about half an hour before you go to sleep) even after a long night. A snack before bed will help keep your energy levels reasonably stable, which is the golden rule of migraine prevention (read more here). Another tip: to discover how much a changing sleep pattern affects your headaches, use the diary in the Headache Hurts app to log the amount of sleep you get. Do this for a while. It makes it easier to spot any connections with your headache.

Lifestyle hacks for night and shift workers

If your part-time job involves working nights or shifts, there are a few things you can do to help prevent headaches.

The big issue: Sleep

Irregular sleep patterns may be the biggest problem for shift workers. Try to keep your sleep-wake cycle as stable as possible, at least when switching from early to late shifts and vice versa. Night shifts are trickier, but there are a few things you can try.

Very bright lighting in the first half of the night (daylight lamps) can help by postponing the onset of fatigue. Also try to integrate short naps of about half an hour during your night shifts, if at all possible. Avoid caffeine during the second half of a night shift or late shift and dim the lighting as much as possible. Bright sunlight on the way home in the morning is counterproductive too. That’s because when darkness fades, your body's natural sleepy-making hormone (melatonin) switches off. Your body wakes up and you won’t be able to sleep. Experts recommend wearing sunglasses if you are going home in broad daylight. Once you get in, darken your room as much as possible to help you fall asleep quickly.

Eating

Having regular meals is important even if you work rotating or split shifts. A hot main meal of lean meat or fish and carbohydrate-rich sides of potatoes, rice or vegetables is recommended. Cold meals might consist of a colorful salad and/or a wholegrain sandwich with plenty of healthy fillings. Staying hydrated is crucial. Aim for a fluid intake of 2-3 liters a day.

Plan to have two meals during your night shift. Your body temperature drops at night. The fall in temperature is a signal telling your body that it’s time to sleep. As well as providing energy, a hot meal helps counteract the drop in body temperature. It also helps you concentrate and stay awake. If hot food is not an option, have some hot tea with your cold meal. Eating your second nighttime meal about two hours before your shift ends will help you stay concentrated and productive. Suitable choices would include vegetable soup, unsweetened fruit puree, milk and dairy products, fruit and light salads. When you get home from your night shift, have a small, not too heavy breakfast before bed.

But beware: a heavy breakfast and caffeinated beverages can make it hard to fall asleep and stay asleep.

Breaks

If you work shifts, try to get in a few short breaks – even if that’s hard to manage, for example if you work in a busy hospital. Ideally, you should use your breaks to get a breath of fresh air. Being outdoors improves the blood flow to your brain, which improves your concentration. Another great tip is Jacobson's progressive muscle relaxation, a medically proven and easy-to-learn relaxation technique. Paying attention to what it feels like to engage and then release your muscles drains away all the tension from your body and makes comparatively short breaks so much more effective. You can access the technique in the Headache Hurts app or here on the website.