A disturbance in falling back to sleep again indicates that one fell asleep without too much difficulty, is soon awake again, and can no longer sleep. This kind of sleep disturbance is very disagreeable for two reasons— because waking up suddenly is often associated with a reaction of more or less strong anxiety, and because a
second attempt at falling asleep is usually more difficult than the first.
There have already been several references to the significant changes in reaction in the autonomic nervous system during the night. These changes are particularly strong during the first deep sleep phase. The depth of the deep sleep phase and the speed with which it is reached varies among individuals, and many persons only reach it once in the course of a night. Some of the changes that occur are changes in the blood supply to the brain, slowing-down of the rate of breathing, and the related electrolyte variations in the blood and the lowering of the blood pressure.
Persons having a tendency toward low blood pressure experience such sensations disagreeably upon awakening. The first deep sleep results in the significant lowering of the blood pressure, and this produces the feeling of anxiety. It begins with restlessness, tossing back and forth, the spiral-patterned worsening of the attempt to force sleep, making it increasingly difficult for the organism's own sleep mechanism to function.
The leveling off of blood pressure that is too low was already discussed under the topic of sleep among the elderly, since fluctuations in blood pressure after the first deep sleep are especially pronounced among this group. But a cup of coffee drunk shortly before going to bed works as a paradox aid to sleep for all persons suffering from hypotension. Medications that generally improve circulation are also most helpful.
The increasing nervousness and anxiety about not being able to fall back to sleep can be dealt with by various methods that facilitate relaxation and then lead to being able to fall asleep again. The first attempt in this direction is to remember that rest is of primary importance. In such instances, the precept of autogenic training, "sleep doesn't matter, but rest is important," can bring about a psychic reversal in which the person stops trying to force sleep and becomes more composed.
An opposite precept (a paradox intention) of trying not to sleep but to remain awake can also help. Additional recommendations are to try to achieve the greatest degree of physical relaxation and to lie on one's back, since lying on one side usually causes certain muscle groups to become tense. If this does not help, then a short air bath in the room (according to Tiegel) should be tried. This consists in walking back and forth in the room for two or three minutes without engaging in any activity such as reading, tidying up, gymnastics, or breathing exercises. Getting back into bed and snuggling into the comfortably warm spot under the covers in the familiar sleep position may then produce quiet and relaxation and possibly even sleep. The question of whether walking, which has a regulative and tonic effect on the circulatory system, or the comforting warmth of the bed promotes sleep is of secondary importance to the person able to get to sleep again by this method. The essential plus factor is that, having experienced success from one's own sensible behavior, one gradually gains new confidence in one's own ability to sleep.