Feeling exhausted all day yet unable to fall asleep at night is one of the most confusing experiences in insomnia — and it comes down to the difference between tiredness and sleepiness. Tiredness is a feeling of low energy; sleepiness is a biological state in which the brain is genuinely ready to fall asleep. People with insomnia have plenty of tiredness but little true sleepiness, and CBT-I works precisely on rebuilding that natural sleep drive.
One of the sentences I hear most often in the clinic is: “I’m wrecked all day… so how can it be that at night I can’t fall asleep?” It really does feel illogical. After all, if the body is tired, sleep should arrive on its own — shouldn’t it?
What is the difference between tiredness and sleepiness?
This is where the crucial distinction comes in. Tiredness is a feeling of having no energy. Sleepiness is a biological state in which the brain is genuinely ready to fall asleep. In people with insomnia there is a great deal of tiredness but very little sleepiness.
Why does this happen?
During the day, mental and emotional tiredness builds up: overload, stress, worry, functioning “on autopilot”. But at night, instead of the system winding down, it actually wakes up. The brain interprets the bed as the moment when control ends: no tasks, no distractions — and then everything that was pushed aside during the day rises to the surface. This is exactly the moment when:
- Thoughts intensify
- The body becomes alert and tense
- And the sleep drive can’t take over
Why does going to bed early backfire?
At this point many people make a natural mistake: they get into bed earlier “because I’m so tired”. But when you get into bed without real sleepiness, the brain learns, again and again, that bed equals wakefulness, thoughts and struggle. The bed loses its link with sleep.
How does CBT-I help?
Cognitive behavioural therapy for insomnia works precisely on this point. It helps to:
- Rebuild a genuine sleep drive
- Separate tiredness from “time to sleep”
- Restore the bed to its natural role
When that happens, many people are surprised to find that it is exactly when they “try less” that sleep begins to arrive. For chronic insomnia, CBT-I is recommended by NICE and the NHS as the first-line treatment, ahead of sleeping tablets.