Why stress breaks sleep
Stress activates the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system. Cortisol rises, heart rate increases, muscles hold more tone, and attention narrows to threat. That is an excellent state for dealing with a deadline and a terrible state for falling asleep.
The mismatch is that stress is often finished by evening in terms of demands, but not finished physiologically. You have stopped working; your body has not stood down.
From acute to chronic: the three behaviours that do it
- Going to bed earlier to catch up. Adds time in bed without adding sleep, dilutes pressure, and trains wakefulness in bed.
- Lying there hoping. Every extra hour strengthens the bed–wake association.
- Napping to compensate. Removes the sleep pressure that would have made the next night better.
Stress starts the fire; these three keep it burning long after the stressor is gone. This is the mechanism behind most chronic insomnia, and it is why the treatment is behavioural rather than calming.
What to do during the stressful period
- Protect the wake time. Same time every morning. This is the anchor that keeps the rhythm stable while everything else moves.
- Keep the bedtime normal or slightly later. Resist the urge to bank sleep.
- Create a stand-down ritual. Fifteen minutes that signals the working day is over: a walk, a shower, slow movement, or a short movement sequence. The content matters less than the consistency.
- Write tomorrow's list before dinner. Not at bedtime.
- Move during the day. Aerobic exercise lowers baseline arousal and builds sleep pressure. See does exercise help sleep.
If it has already become chronic
If the stress has passed and the insomnia has not, the problem is now the learned pattern rather than the stressor. That is good news, because learned patterns respond to CBT-I — specifically stimulus control and sleep restriction. See chronic insomnia.
The physical residue
People under sustained stress hold their bodies differently — jaw, shoulders, diaphragm, lower back — and often stop noticing. If you recognise that, and especially if breathing exercises feel like they do not reach it, try Feldenkrais work: small movement, low effort, aimed at letting go of holding rather than at calming down.