Sleep maintenance insomnia: what to do when you cannot stay asleep?

Falling asleep and staying asleep are two different regulatory tasks. Whoever falls asleep has enough sleep pressure and a sufficiently lowered arousal level. Staying asleep means that this lowered level is held over several hours. In the early morning hours, the cortisol level physiologically rises because the body prepares for waking. With an overactive stress system (hyperarousal of the HPA axis, described by Vgontzas 2002 in Endocrinology and Metabolism Clinics), this rise can occur too early and too strongly, so that you wake up. A second mechanism is the nocturnal drop in blood sugar: if the glucose level falls too low, the body releases adrenaline and cortisol to counteract it, and that can wake you. A third factor is REM instability: Riemann 2012 in Pharmacopsychiatry describes that people with insomnia show increased micro awakenings during REM sleep, the most superficial sleep stage, which increases toward morning. Alcohol in the evening worsens this because it disturbs REM sleep in the second half of the night (Gardiner 2024 in Sleep Medicine Reviews).

Yes. Brief nocturnal waking phases are physiological. Sleep runs in cycles of about 90 minutes, and at the end of each cycle, especially in the second half of the night, you lie briefly in a superficial stage or wake for seconds to a few minutes. Most people do not remember it in the morning. It only becomes a problem when falling back asleep takes a long time, when the awakening goes along with rumination, palpitations or tension, or when sleep is no longer restorative as a result. We speak of insomnia requiring treatment when the sleep disturbance occurs at least three times per week over at least three months and leads to daytime impairment. A single brief awakening is not a sign of illness, a pattern of long wakefulness and daytime tiredness is.

A targeted basic workup makes sense, not a scattershot. First ferritin and transferrin saturation: an iron deficiency can trigger or worsen a restless legs syndrome that fragments sleep. Gossard 2021 in Neurotherapeutics names iron measurement as the standard when suspected and recommends iron therapy with reduced iron stores. Second TSH and possibly fT3 and fT4: the thyroid influences sleep, an overfunction typically goes along with restlessness and nocturnal awakening. Petrov 2024 in Sleep Medicine also shows that sleep deprivation itself influences the thyroid axis, especially in women. Third vitamin D, because a pronounced deficiency is associated with poorer sleep quality. Fourth magnesium in whole blood. Fifth, in women in perimenopause, the hormonal situation, because the drop in progesterone often goes along with sleep maintenance problems. These values belong in a clinical context, not interpreted in isolation. A lab does not replace a medical examination.

Regular waking around 3 a.m. is a common and well explainable phenomenon that is often interpreted esoterically with an organ clock. Medically considered, this time falls into a phase in which the body core temperature is at its lowest and the cortisol level begins its morning rise. In this window sleep is especially light and prone to disturbance, the proportion of REM sleep increases, and small triggers such as a blood sugar dip, a full bladder or a mental stimulus can be enough to wake you. Whoever also has an overactive stress system reacts more sensitively to the natural early morning cortisol rise. So it takes no mystical organ clock to explain waking up at 3 a.m., but chronobiology and stress physiology. We cover the mechanics behind it in depth in the spoke on the 3 a.m. cortisol.

That is a plausible mechanism that can be more or less pronounced individually. If blood sugar falls too low at night, the body reacts with a counter regulation: it releases the stress hormones adrenaline and cortisol to free glucose from the stores. These hormones act in an activating way and can wake you, often with palpitations, inner restlessness or sweating. Very carbohydrate rich or sugar rich late meals that lead to a rapid rise and then a steep drop in blood sugar are favoring factors, as is alcohol in the evening, which throttles the nocturnal sugar release of the liver. Whoever has the suspicion can observe whether a balanced, not too late dinner with protein and fiber instead of a fast carbohydrate load reduces the nocturnal awakening. That is an observational hypothesis, not a diagnosis, and does not replace a medical examination.

For chronic insomnia, cognitive behavioral therapy for insomnia (CBT-I) is the first line recommendation, because it may work sustainably, without habituation or dependence. Trauer 2015 in Annals of Internal Medicine summarized in a meta-analysis of 20 randomized trials with 1162 participants: CBT-I shortened nocturnal wake time after sleep onset (WASO) by an average of 26 minutes and the time to fall asleep by 19 minutes, without reported adverse effects, with a lasting effect over time. WASO in particular is the decisive value for sleep maintenance insomnia. Hertenstein 2022 in Sleep Medicine Reviews confirmed the effectiveness also in people with additional mental disorders. Sleeping pills such as Z substances or benzodiazepines can help short term but carry the risk of habituation and dependence with long term use. The clean order is therefore: first the behavioral and root cause level, substances only in a targeted and time limited way. We cover CBT-I itself in detail in its own spoke.

Magnesium may have a supporting effect but is not a sleeping aid and does not replace clarifying the cause. Mah 2021 in BMC Complementary Medicine and Therapies summarized three randomized trials in older people with insomnia: oral magnesium shortened the time to fall asleep by an average of about 17 minutes versus placebo, the extension of total sleep time was not statistically significant, and the authors rated the quality of the evidence as low. Hausenblas 2024 in Sleep Medicine X found in a placebo controlled trial with magnesium L-threonate indications of better subjective and partly objective sleep quality. Overall the data situation is moderate. Magnesium is inexpensive, broadly available and, with normal kidney function, well tolerated, a trial over a few weeks may be sensible. But whoever wakes up because of an iron deficiency, a thyroid disorder or an overactive stress system will not hit the cause with magnesium alone. We cover the different magnesium forms in their own spoke.

A medical evaluation is sensible when the sleep maintenance insomnia exists at least three times per week over more than three months and impairs the day, when loud snoring with breathing pauses is noticed (suspicion of sleep apnea), when restless or tingling legs disturb falling asleep and staying asleep (suspicion of restless legs syndrome), with pronounced daytime tiredness and a tendency to fall asleep, with palpitations, weight loss or heat intolerance (suspicion of thyroid overfunction) and always with accompanying depressive mood or anxiety. Also when sleeping pills have already been taken over a longer time, that belongs in medical supervision. This text serves information and does not replace a medical examination, diagnosis or treatment.