Sleep can both trigger or terminate a migraine attack. Dreaming occurs during the sleep stage called REM (rapid eye movement) sleep, and REM sleep may be a very powerful trigger for both migraine and cluster. Most of your REM sleep occurs in the early morning. If you awaken at 4:00 am with a migraine and then go back to sleep, you often will find that you will spend a great deal of time dreaming, only to awaken shortly thereafter with a yet worse headache. These headaches often persist throughout the day, and they are typically very hard to terminate. It therefore is important to treat a headache when you awaken and not just go back to sleep hoping it will disappear. Since time is critical to the effective treatment of acute migraine, you need to realize that you are usually quite behind when you treat a headache that is present upon awakening. You understandably may resist getting up, but the best way to rid yourself of that headache for good is to get out of bed and take your abortive medication before going back to sleep.

When you oversleep, you also are fasting, and this may play a role in "oversleep headache" Depression or anxiety commonly produce disrupted sleep, and this may aggravate your headache syndrome. Finally, some people have sleep apnea syndrome. They tend to be overweight and to snore loudly. If observed, they exhibit prolonged periods during sleep when they do not breathe. The most common manifestation of the disorder is excessive daytime somnolence, but awakening with headache also is common. If sleep apnea syndrome or another sleep disorder is suspected, you may be referred for a study called a polysomnogram.

Strong odors (e.g., those associated with perfumes and certain aftershave lotions) often are identified as migraine triggers, and automobile exhaust fumes can trigger attacks as well. Migraineurs instinctively appreciate a well-ventilated environment. Smoking triggers headaches in some migraineurs, as does "second hand exposure" to cigarette, cigar, or pipe smoke.

As discussed previously, the visual cortex of the brain appears to play a major role in producing visual aura and indeed may serve as the generator of the entire migraine attack. Not surprisingly, various visual stimuli may trigger migraine. One such stimulus commonly cited by migraineurs is exposure to fluorescent light, especially if that light is flickering. Photophobia (light sensitivity) is common during acute migraine attacks, and many individuals with chronic migraine note persistent photophobia even during the intervals between attacks. Such individuals may find that tinted glasses are helpful in reducing headache susceptibility as well as the photophobia itself.