This instruction often receives the most resistance, for understandable reasons. You are exhausted, the bed is warm and getting up at 3 a.m. can feel completely unreasonable.

The explanation begins with what you learned in Lesson 1. Every period you spend awake in bed, trying to sleep, checking the time or waiting for sleep to return, reinforces the idea that the bed is a place to be awake.

If this happens repeatedly, getting into bed can begin to trigger alertness instead of sleep. The technical term for this is conditioned arousal.

Getting up when you cannot sleep helps break that conditioning. It may not improve the current night immediately. Instead, it gradually weakens the association between bed and wakefulness over the following days and weeks. The aim is for your bed to become strongly associated with sleep again.

The rule. If you have been lying awake for about 20 minutes and do not feel close to sleep, get up.

You do not need to watch the clock or measure the time precisely. Use 20 minutes as an estimate and ask yourself: Does it feel as though sleep is coming? If the honest answer is no, leave the bed.

What to do instead. Go to another room and choose something quiet that does not require much stimulation. You might read under a soft light, stretch gently or listen to something calming.

Avoid screens if you can. Avoid going to the kitchen if that creates another source of worry. Try not to choose an activity that feels like a reward for staying awake. The goal is simply to be awake somewhere other than your bed.

Return to bed when you feel sleepy. Sleepy is different from tired or bored. Look for physical signs such as heavy eyelids or difficulty maintaining your focus.

If you return to bed and remain awake for another 20 minutes or so, get up again. Repeat the process whenever necessary.

The first week can feel more difficult because you may spend more time out of bed and feel more tired. The association between bed and sleep does not change immediately.

This temporary discomfort helps build stronger sleep drive. Over time, that increased drive can make sleep more likely and help restore the connection between your bed and sleeping.

The same rule applies at the beginning of the night. Do not go to bed until you feel sleepy.

Being tired is not the same as being sleepy. Tired means that you have little energy. Sleepy means that you feel a physical pull toward sleep.

Going to bed because you are tired, without feeling sleepy, often means going to bed while you are still awake. That is the association this exercise is designed to change.