Insomnia and Biphasic Sleep: How We Were Meant to Sleep
“I fall asleep fine, but I wake up at 2 or 3am and can’t get back to sleep.” This pattern — sleep maintenance insomnia — is among the most common complaints in adult health care. It is almost universally treated as a pathology: the body failing to maintain sleep appropriately.
Evolutionary medicine offers a strikingly different interpretation.
The Biphasic Sleep Hypothesis
Historian Roger Ekirch spent 16 years researching preindustrial sleep patterns across historical documents from across Europe and the world. What he found was remarkable: before the widespread introduction of artificial lighting, people routinely slept in two distinct phases.
“First sleep” began at dusk and lasted until roughly midnight. Then came a period of natural waking — 1–2 hours of quiet activity: prayer, conversation, sexual intimacy, reading, or simply contemplative rest. Then “second sleep” resumed until dawn.
This pattern — sometimes called biphasic or segmented sleep — appears across historical records from medieval Europe, Africa, South America, and Southeast Asia. It appears to be the natural human sleep architecture in the absence of artificial light.
What Happens During the Night Waking
The period between first and second sleep is not normal waking. Modern sleep researchers have identified it as a distinct state — characterised by elevated prolactin, dreamlike cognition, and a meditative, non-anxious quality. It is the period when memory consolidation and the clearance of cellular waste products from the brain (via the glymphatic system) continue in a partially different physiological mode.
People who experience this waking in modern settings typically panic about “not sleeping” — activating the stress response, which then genuinely prevents return to sleep. The insomnia is, in part, the anxiety about the waking — not the waking itself.
The Artificial Light Revolution
The introduction of reliable artificial lighting extended the social day, compressed the sleep window, and created cultural pressure for a single block of consolidated nocturnal sleep. Eight uninterrupted hours became the norm and the ideal. This norm is approximately 150 years old. Our ancestral sleep patterns are approximately 300,000 years old.
OQ’s Approach to Sleep
Sleep is the foundation of physiological regulation. Poor sleep amplifies pain, suppresses immune function, disrupts hormonal balance, and is the single most powerful predictor of next-day mood and cognitive function.
At OQ, sleep quality is assessed as part of the whole-body picture. The autonomic nervous system state — particularly vagal tone and sympathetic/parasympathetic balance — is directly relevant to sleep architecture. Osteopathic treatment that improves autonomic balance often produces meaningful improvements in sleep quality, even before any behavioural changes.
FAQ
Should I try to sleep in two phases?
For some people, accepting and working with natural night waking — rather than fighting it — reduces the anxiety that makes it worse. Quiet, light-free activity during the waking period and returning to bed when sleepy again can be more effective than lying awake anxiously trying to force sleep.
Why does modern insomnia seem so much worse than it used to be?
Screen light (blue spectrum) suppresses melatonin. Social media and news activate the sympathetic nervous system. Sleep schedule irregularity disrupts circadian rhythms. Modern insomnia is the compounding of multiple factors on an already challenged system.
Can osteopathy help with sleep?
Yes. Autonomic regulation, pain reduction, breathing mechanics, and nervous system calming all respond to osteopathic treatment — and all directly affect sleep quality.
Poor sleep affecting everything else? The nervous system, not just “sleep hygiene,” may be the key. Book →