It is no accident that the majority of people sleep at night and are awake during the day. This pattern of sleep-wake is determined by the body’s internal clock, giving rise to our circadian rhythm. Like alarm clocks, our internal clock needs to be reset every day, and this happens by exposure to daylight.

Disruption of our circadian rhythms is linked to several brain disorders, and new research is now highlighting its importance for migraine.

Everyone’s own internal clock is slightly different and new research has shown that the timing of your internal clock can predict the time of day you are most likely to get your migraine attacks. For example, if you are a ‘morning lark’, rising early, your attacks are more likely to occur early in the day; whereas ‘night owls’, who rise later and function better later in the day, tend to have their attacks later.

In addition, our recent preclinical research part funded by The Migraine Trust has shown that alteration of circadian rhythms, for example by modelling shift work or jet lag, can increase attack susceptibility.

Circadian rhythms are genetically determined

There is no way to change your own predisposed circadian rhythm since it is genetically determined. However, there are several ways to ensure that you are maintaining good circadian hygiene. This is centred on consistent sleeping patterns that match your own internal body clock.

For example, try to shift your social/work life to match your circadian rhythm: if you are more of a ‘night owl’ you might consider jobs that permit a later start time, with the added bonus that you will be more productive later in the day. Additionally, limit your exposure to ‘social jetlag’ where staying up late and sleeping in on the weekend results in a shift in your rhythm that come Monday, you abruptly shift back by having to wake up early for work.

Importantly, it takes one day to recover for every hour of circadian disruption, so that simple weekend shift of three to four hours can disrupt your internal clock for three to four days.

Exposure to natural light

One of the most important things you can do to regulate your clock is to get regular exposure to natural light every morning. Our internal clock needs brief exposure to light levels of greater than 1,000 lux (equivalent to an overcast day) to enable it to reset. This might sound easy but when we consider Covid-19 restrictions and the fact that most households and workplaces only provide low levels of artificial light (about 100-200 lux), this can prove to be a challenge.

However, one of the best things you can do is go for a morning walk.

On the other hand, as light is a cue for our bodies to wake, exposure to light late in the day can disrupt your clock. Therefore, it is best to avoid bright light/screen time for 60-90 minutes before bedtime and consider using dim lighting instead. This will help you to sleep more soundly and regulate your clock.

While our research is continuing to uncover exciting new interventions to help minimise the impact of circadian disruption on migraine, as always, clinical translation can take time. So in the meantime, try to follow the simple guidance above to help you maintain your natural rhythm to reduce the impact of circadian disruption on your migraine.