A migraine trigger is any event, change, external or internal factor, or physical act, that can result in migraine. There is no one single migraine trigger. In a study at the City of London Migraine Clinic, 79% of the patients questioned were aware of factors that they thought triggered their attacks. However, most of them noted that several factors acting together were needed to bring about an attack. Migraine triggers are many and varied but are no different from the factors that provoke ʻnormalʼ headaches in apparently non-migrainous individuals.
Neither are triggers the same for everybody, or even necessarily the same for different attacks in the same individual.
A few people are aware of at least some of their triggers. Others are confused when a suspected trigger sometimes results in an attack, but not every time. Understanding your migraine triggers can help you unravel the mystery of why you get migraine attacks. Imagine that your body has a ʻmigraine thresholdʼ, which allows you to tolerate the effect of migraine triggers without ill effect until this threshold is crossed. Varying triggers occur over a period of time and act by building up in combination, until they cross your migraine threshold. At this point a migraine attack occurs.
This explains why apparently similar situations do not always result in a migraine attack.
Your ʻmigraine thresholdʼ can fluctuate and the number or importance of triggers can vary. An example to illustrate this might be that missing a meal, or less obvious triggers such as flickering sunlight or a lack of sleep, may not always bring on an attack. However, if any or all of these are combined with a period of stress or (in female patients) hormonal changes, an attack may occur. By identifying and addressing your triggers, you may reduce the frequency of attacks and use less medication. Many patients find it possible to prevent migraines by modifying their lifestyle and preventing interaction of their migraine triggers.
Certain foods, in particular cheese, chocolate, alcohol, citrus fruits, dairy produce, and many others have been implicated in triggering migraine. However, the true link with migraine is uncertain as craving for specific foods can occur as part of migraine, before the headache starts – the premonitory stage.
Also, because several factors are necessary to trigger an attack it follows that if other factors can be identified and minimized, then food triggers will be less important. If you suspect that any foods do trigger an attack, cut them out of your diet for a few weeks before reintroducing them.
Delayed or missed meals often result in a relative drop in blood sugar, triggering migraine. This is usually the most important trigger in children particularly when they are going through a growth spurt or involved in strenuous exercise. It explains why many children come home from school with a bad headache – they just havenʼt had sufficient to eat, often enough. But insufficient food may also be an important migraine trigger in adults.
Missing breakfast typically triggers attacks late morning; missed lunch may trigger attacks late afternoon. If attacks are present on waking it is worthwhile considering the time you eat your evening meal – which may be quite early. A bowl of cereal last thing at night might be all you need to treat your migraine. Many migraineurs find that they need to eat frequent snacks every four hours or so during the day to avoid the peaks and troughs in blood sugar. Sugary snacks and chocolate are fine to eat – but at the end of meal and not in place of one.
Mild dehydration can have an impact on people who have migraine. It is recommended that you should drink at least 8 glasses of water per day. This is in addition to any other drinks you may have. Fizzy drinks can contain the sweetener aspartame, which some people link to their migraines.
The most frequently cited trigger is alcohol. Certain types of alcohol contain chemicals that can either directly affect blood vessels or provoke the release of other chemicals thought to be involved in migraine. In this respect the migraineur is sensitive to certain components of the alcoholic drink. Certain red wines contain more of these potent chemicals and are therefore more likely to trigger an attack than pure drinks such as vodka.
Excessive consumption of caffeine may contribute to the onset of migraine. You could try not having more than 4 or 5 cups of tea, coffee and cola in a day. Some people find that suddenly stopping caffeine altogether can also be a trigger factor. For example, if you regularly drink caffeine-containing drinks at work but get migraines on your day off, the trigger may be caffeine withdrawal. If you suspect this, you may wish to cut down on caffeine more gradually. Note that caffeine can be found in many products including chocolate and over the counter painkillers.
Migraine is often present on waking. Lack of sleep is recognised as a migraine trigger. Conversely, sleep during an attack may resolve symptoms. However, the true association between migraine and sleep is poorly understood. Other factors may also be important. For example, lack of sleep can result from depression, anxiety, menopausal hot flushes or delayed bedtime due to social events, work or study. Each of these could be a migraine trigger in its own right.
Many people notice that sleeping in for even just half an hour longer than usual, or lying in bed dozing, can result in migraine. This may be one cause for weekend migraine. What is clear is that if you suffer from migraine, try to keep to a fixed sleep pattern going to bed at night and getting up in the morning at regular times. Shift workers3 should try to avoid frequent changes of shift times, where possible.
Change in routine
Some people find that changes in their routine can contribute to a migraine. For example changing sleep patterns or changes caused by long journeys can precede an attack. Even pleasant changes such as a holiday can be implicated.
Migraineurs who work Monday to Friday often report that their migraine is more likely to occur at a weekend. This pattern
is most likely to result from a gradual build up of triggers during the week, culminating in an additional barrage of triggers at the weekend – relaxation after stress, perhaps late to bed on Friday night following an evening out, sleeping in on Saturday morning and altered eating patterns – often with a late breakfast. It is not surprising that an attack of migraine results. Caffeine withdrawal, following a reduced caffeine intake at weekends compared to the working week, has also been implicated. Many sedentary workers take unaccustomed exercise at weekends with housework, gardening and DIY projects to be done.
Anxiety and emotion play an important role in headache and migraine. Many migraineurs cope with stress without having more migraine at the time but have attacks when they relax (e.g. after meeting a deadline at work; after a big event such as a wedding; on the first day of a holiday). However, stress rarely occurs without a knock-on effect upon other triggers, often resulting in missed meals, poor sleep and increased muscle tension. Although stress is often unavoidable, it is important to try to reduce the effects of other avoidable triggers by eating regularly and getting adequate sleep. This can also help you cope with the stress better.
How often have you found that a long journey by car or airplane results in a migraine? Travel is associated with a host of potential migraine triggers: lack of sleep from preparation for the trip and from the trip itself, stress, missed or delayed meals, noise, and dehydration. If youʼre travelling by plane there are the added triggers of dehydration and cramped seats with little room to move. It remains uncertain as to whether pressure changes in aircraft triggers migraine, particularly with improved cabin pressures in most modern planes.
For centuries the seasonal hot dry winds around the world such as the Swedish Föhn, the Mediterranean Meltemi and the Canadian Chinook, have been associated with headache and general irritability. In other parts of the world less obvious changes in barometric pressure have been cited as a trigger for migraine although the data are conflicting. In the UK, although a study in London found no evidence for an effect of weather on migraine, the results of a study in Scotland suggested that a rise in barometric pressure was associated with increased migraine frequency.
Computers are often implicated as a cause of headache. The cause is both related to the flickering screen and also how you sit and work at the computer. Consider using anti-glare screens; positioning your monitor in daylight, rather than under fluorescent lighting; changing the refresh rate of your computer monitor; and checking whether you may need glasses for close-up work, such as computer work or reading.
If you do get headaches or migraines after working at a computer for long periods of time, set an alarm to sound every half an hour to remind you to take a short break. Look at something as far into the distance as you can, blink your eyes hard several times, and try some simple and quick exercises to stretch the neck and shoulder muscles. Even just gently rolling your neck and stretching out your arms can make a great deal of difference.
If you are unfit, strenuous exercise is likely to trigger an attack, as well as muscle aches and pains. This puts many people off taking exercise when in fact regular exercise can help prevent migraine. A new exercise programme should start off gently, building up the pace gradually over several weeks. It is important to keep the exercise sessions regular. Short frequent sessions are more beneficial than long infrequent sessions – the latter sometimes doing more harm than good. Fit people have improved blood sugar balance, better breathing, and better pain control compared with unfit people – exercise stimulates the body to release the natural pain controlling chemicals known as endorphins and encephalins, relieves depression, and promotes a general sense of well being. However, it is not all good news. Children appear to be particularly susceptible to the effects of strenuous exercise, developing migraine following a hard game of football. In many cases, drinking lots of fluids and sucking glucose tablets before and during exercise can prevent these attacks.
In a study undertaken at the National Migraine Centre , more than 50 per cent of women reported that they were more likely to have a migraine attack around the time of their menstrual period. Although most women have attacks at other times of the cycle as well, a small percentage of women only have attacks that are exclusively associated with menstruation. These attacks can be usually be controlled with standard migraine management strategies. A few women with obvious hormonal triggers may benefit from specific intervention. Other hormonal changes such as use of hormonal contraception can exacerbate migraine for some women and improve it in others. The years leading up to the menopause are typically associated with increased frequency of migraine, particularly menstrual migraine. The hormonal fluctuations associated with worsening of migraine at this time can be controlled using hormone replacement therapy, which is particularly indicated if other menopausal symptoms such as flushes and sweats are present.
Most people will get a headache when they have a cold or viral infection, but migraine can also occur. It is uncertain whether the illness is a trigger in its own right or if being ill lowers the attack threshold so that fewer triggers are necessary before an attack results. If youʼre coming down with a cold, stock up with migraine treatments as well as cold remedies but make sure that you donʼt overdose on painkillers.
Neck and back pain
Neck and back pain can trigger attacks, particularly if it results from a specific injury but even simple muscle tension from poor posture, sitting in front of a computer or driving a car can be a cause. Physical causes such as these require physical treatments, although it may be several months before you see any benefit. Sometimes, over-enthusiastic oesteopathy or physiotherapy can trigger attacks. Like exercise, a gentle start is the key to long-term benefit.
Jaw joint dysfunction
If you find that your jaw ʻclicksʼ when you eat or even locks out, or you frequently wake with migraine after grinding your teeth at night, you may have a problem with your jaw joint. Pain and tenderness in the jaw joints can be associated with tension in the muscles controlling the jaw. This may lead to headache, often daily, but can also trigger migraine. One young girl with daily headaches and tender jaw joints found that all her symptoms resolved when she stopped chewing gum!
Keep a trigger diary, separate from your record of migraine attacks. This can just be a notebook, using a separate page for each day. Look at the list of common triggers every day, just before you go to bed. Make a note of any that you suspect
were present that day. This is important, as you are unlikely to remember triggers clearly when you have an attack. Women should keep a record of their menstrual period and any premenstrual symptoms. You should continue to complete the trigger diary and the attack diary until you have had at least five attacks.
Rather than ‘What triggers a migraine attack?’, a more useful question is ‘How many triggers do you need to initiate an attack?’. Even your usual daily routine can include triggers that you are not aware of because you remain below the threshold of an attack until a few extra triggers crop up.
Compare your trigger diary with your attack diary and see if there was a build up of triggers during the days before each attack. You should be able to divide your list of triggers into two groups – those that you can do something about (e.g. missing meals, drinking red wine) and those that are out of your control (e.g. menstrual cycle, travelling). First try to deal with the triggers that you have some influence over. Cut out suspect triggers one at a time – if you try to deal with them all at once you will not know which are most relevant to you. Try to compensate so that if you are having a particularly stressful time, take care to eat regularly and find ways to unwind before you go to bed. If your attacks regularly start late morning or late afternoon, look at your mealtimes. A mid morning or mid afternoon snack may be all that is necessary to prevent the attacks. Similarly if you have an early evening meal and wake with an attack, try a snack before you go to bed.
Although it takes a great deal of motivation and effort to identify and deal with migraine triggers, studies have shown that the number of attacks can be halved. This is as effective as taking some of the daily preventive medications – but without drugs!
This information is provided as a general guide only and is not a comprehensive overview of prescribing information. If you have any queries or concerns about your headaches or medications please discuss them with your GP or the doctor you see at the National Migraine Centre