Sleep is one of the few states a person cannot enter deliberately. That fact explains why trying to sleep is counterproductive and why insomnia becomes self-sustaining.
Sleep is permitted rather than performed
Falling asleep involves a withdrawal of the systems that maintain wakefulness, which means the transition happens when something stops rather than when something is done.
No voluntary action produces it, unlike walking or holding one's breath, so the ordinary strategy of applying more effort has no mechanism to act through.
Effort instead recruits attention and arousal, both of which support wakefulness, so trying harder pushes in exactly the wrong direction.
Monitoring keeps the system awake
Checking whether sleep is arriving requires attending to one's own state, and that attention is an alerting activity by nature.
Clock-watching intensifies this, adding a running calculation of hours remaining and consequences tomorrow, which supplies arousal on top of the monitoring itself.
This is why the same person falls asleep instantly in front of a television, where nothing is being monitored and no outcome is at stake.
The bed acquires a learned association
Repeated nights of lying awake pair the bed with wakefulness, worry and frustration, and that pairing operates automatically once established.
People with long-standing insomnia often report falling asleep readily on a couch and waking on entering the bedroom, which is the association acting directly.
Because it is learned rather than chosen, reasoning about it does not dissolve it, and the association persists after the original cause of the sleeplessness has resolved.
Sleep pressure and clock timing must align
Sleep depends on accumulated pressure from time spent awake and on the circadian signal that opens a window for sleep at particular hours.
Spending long periods in bed dilutes pressure across more hours, which produces lighter, more fragmented sleep and more time awake in bed.
This is the reasoning behind structured insomnia programs that concentrate time in bed, and it explains why they are counterintuitive to people already sleeping poorly.
Why this is clinical territory
Structured behavioral programs for insomnia are delivered by trained providers because the schedules involved temporarily increase sleepiness and require monitoring and adjustment.
Insomnia also accompanies other conditions, including breathing disorders, pain and mood conditions, which changes what is appropriate and cannot be sorted out from the outside.
Persistent difficulty sleeping that affects daytime functioning warrants an evaluation by a licensed clinician rather than a routine assembled from general reading.