Cluster, migraine and tension-type headaches may produce a headache that awakens an individual in the early morning hours (usually after 4 AM), or is present upon awakening. Those individuals with chronic tension-type headache are most likely to be awakened in the early morning hours due to headache. This headache also tends to be at its worst severity at that time of day. A variety of causes may account for this early-morning pattern to the headaches.
Depression is most often associated with chronic tension-type headaches. Additionally, withdrawal effects from pain medications, ergots and caffeine often produce this pattern. Several important physiological changes that occur during these early morning hours can influence migraine and tension-type headache, as well as symptoms other than headache.
Between about 4 AM and 8 AM, the body tends to produce less of its natural painkillers, the endorphins and enkephalins, than at other times of the day. Adrenalin is released in larger quantities during the early morning hours. Since adrenalin affects blood pressure and the regulation of dilation or contraction of the blood vessels, it may play a role in migraine attacks.
Serious diseases may cause early morning awakening headaches. These diseases may include brain tumors, sleep apnea, and severe high blood pressure.