When Sleep Hygiene Isn’t Enough: Persistent Sleep Problems and the Nervous System

Sleep is a really important part of your overall health.

You can feel it after a poor night, and it can compound after multiple nights without good sleep. Small frustrations can more easily become anger or resentment. Focus drops, your phone becomes harder to put down, and socialising can start to feel like effort rather than enjoyment.

Sleep isn’t just where we rest at night. It is where emotional experiences are processed, memory consolidates and the body recalibrates.

A lot of sleep advice focuses on sleep hygiene: eating earlier, reducing screens at night, getting morning light, exercising regularly, keeping a consistent wake time. These things can genuinely help, and for many people they make a noticeable difference.

But if sleep remains disrupted over months or years, even after making those kinds of changes, it may not simply be a problem of routine or discipline. It may reflect a nervous system that struggles to fully settle.

Persistent sleep disturbance can have many contributing factors, including medical, hormonal, neurological, psychological, and lifestyle factors. Here I’m focusing specifically on one pathway that is often overlooked: chronic autonomic activation and difficulty settling into a felt sense of safety.

In Putting Trauma to Sleep, Jaan Reitav and Celeste Thirlwell describe how sleep disturbance can be linked with dysregulation in brainstem systems involved in basic rhythms such as breathing, heart rate, arousal, and sleep. When the system remains organised around threat, symptoms such as insomnia, nightmares, chronic tension, and feeling constantly “on edge” can persist.

The Nervous System Behind Sleep

Sleep is not something we can force with effort. It tends to come when the body is able to shift from activation toward rest.

The autonomic nervous system regulates many of the body’s automatic processes, including heart rate, breathing rhythm, digestion, blood pressure, and arousal. Most of this happens outside our conscious awareness.

For the purposes of sleep, two branches are especially relevant:

The Sympathetic Nervous System

The sympathetic branch mobilises the body for action. It is often associated with fight or flight, but its role is broader than emergency survival. It helps us focus, respond to pressure, meet demands, and protect ourselves when necessary.

The problem is not sympathetic activation itself. The problem can arise when the system struggles to return to rest. Over time, this can show up as chronic muscle tension, shallow breathing, irritability, scanning for problems, or difficulty relaxing even in safe environments.

The Parasympathetic Nervous System

The parasympathetic branch supports settling, restoration, digestion, and recovery after stress. It helps slow the heart, soften muscle tone, and bring the body back toward a state of safety.

The vagus nerve plays an important role in this process, linking the brainstem with the heart, lungs, and digestive organs. When parasympathetic activity is available, the body is generally more able to settle after activation.

For sleep to unfold naturally, the body needs to shift from readiness toward rest. If sympathetic activation remains elevated, you may feel exhausted but still unable to let go. This can look like lying in bed with racing thoughts, shallow breathing, muscle tension, or a restless sense that your body cannot quite settle.

For some people, breathing exercises or relaxation techniques are enough to support this shift. For others, they may help briefly, or not at all. In these cases, sleep disturbance may reflect a nervous system that has difficulty disengaging from vigilance.

Trauma, Attachment, and Vigilance

Not all sleep problems are caused by trauma or attachment wounds, but for some people, sleep difficulties make more sense when understood as part of a broader pattern of vigilance.

Over the past decade, researchers have begun to look at sleep differently in the context of trauma. Instead of seeing sleep problems as just a side effect of PTSD, they are recognising that poor sleep can actually worsen trauma symptoms and help maintain them.

One reason is that the systems involved in detecting threat are closely linked with the systems that regulate arousal and sleep, including brainstem systems that help govern basic rhythms such as breathing, heart rate, and sleep-wake states.

If you have lived through overwhelming events, chronic stress, or early attachment instability, your nervous system adapts. It may become more vigilant, learning that remaining slightly prepared is safer than fully letting go.

The nervous system that supports sleep does not develop in isolation. Our capacity to down-regulate into rest is shaped through repeated experiences of safety, predictability, and co-regulation. When those experiences have been inconsistent, overwhelming, or absent, the body may become more practised at staying prepared than letting go.

During the day, this can look different for different people. Some people become highly productive and unable to switch off. Others feel exhausted, irritable, emotionally flat, restless, foggy, or easily overwhelmed. Some move between both: pushing through the day, then collapsing when there is finally space to stop.

At night, the underlying activation can become more noticeable. You may notice shallow breathing, tension in the jaw, neck, shoulders, chest, or belly, or a sense that your body is tired but not fully able to let go.

In this context, sleep difficulty may not be only a behavioural issue. Your body may need to experience enough safety to settle, so sleep can unfold more naturally.

Where Therapy Can Help

If you consistently struggle with sleep, this may show up in different ways: difficulty falling asleep, waking through the night, frequent nightmares, or waking exhausted even after seven or eight hours in bed.

If this is happening alongside other signs of nervous system activation, such as emotional dysregulation, chronic muscle tension, restlessness, irritability, or difficulty feeling settled, and sleep hygiene changes have not been enough, it may be useful to look beyond sleep routine itself and consider what is keeping the nervous system activated.

Therapies such as Somatic Experiencing can be helpful here because they work with the body’s patterns of activation, bracing and settling. Rather than trying to force relaxation from the top down, the process often involves gently tracking sensation, noticing where the body braces, supporting the breath to soften, and helping your system move out of chronic vigilance at a pace it can tolerate.

Over time, this kind of therapy may help:

•        Reduce chronic muscular bracing.

•        Support slower, more diaphragmatic breathing.

•        Increase the body’s capacity to settle after activation.

•        Build tolerance for internal sensations without becoming overwhelmed.

•        Allow unresolved emotional material to be processed without the body needing to remain on guard.

•        Develop a greater embodied sense of safety in relationship.

As your body becomes more able to return to a settled baseline, sleep may begin to change as a by-product. Not because you are trying harder, but because your nervous system no longer needs to remain so organised around vigilance.

Further reading:

Fogel, A. (2009) The psychophysiology of self-awareness: Rediscovering the lost art of body sense. New York: W.W. Norton & Company.

Germain, A. (2013) ‘Sleep disturbances as the hallmark of PTSD: Where are we now?’, American Journal of Psychiatry, 170(4), pp. 372–382. doi: 10.1176/appi.ajp.2012.12040432.

Koffel, E., Khawaja, I.S. and Germain, A. (2016) ‘Sleep disturbances in posttraumatic stress disorder: Updated review and implications for treatment’, Psychiatric Annals, 46(3), pp. 173–176. doi: 10.3928/00485713-20160125-01.

Reitav, J. and Thirlwell, C. (2025) Putting trauma to sleep: Attachment-based neuromodulatory interventions for stabilizing the brainstem. New York: W.W. Norton & Company.

Spoormaker, V.I. and Montgomery, P. (2008) ‘Disturbed sleep in post-traumatic stress disorder: Secondary symptom or core feature?’, Sleep Medicine Reviews, 12(3), pp. 169–184.