Waking up tired: causes and what to do.

Waking up tired after seven hours' sleep is infuriating. In bed by eleven, alarm at six, and no sign of any rest.

"I get my six or seven hours and still wake up shattered." I hear that a lot from the people I work with. Most people look for the fix in the night itself, a new mattress or an extra half hour. Often it lies earlier, in the evening and across the day.

How to spot it

• The fog doesn't lift. Some fog on waking is normal. This lasts until mid-morning.
• You run on coffee. One to get going, another to make it to ten.
• You sleep in at weekends. And Monday often feels worse.

Why do I wake up tired after seven hours' sleep?

Usually because your sleep was light or broken. What recharges you most is deep, unbroken sleep, and that's often missing even from a long night.

The night has two halves. Nearly all your deep sleep sits in the first, helping to repair your body and clear your brain. The second is mostly dreaming sleep, linked to memory and mood.

The wake-ups you don't remember. A warm room or slow digestion can pull you to the surface for a few seconds. If your breathing keeps stopping, it can happen dozens of times a night, and that's for a doctor to assess.

Your body clock wants a timetable. Go to bed and get up at a different time every day and your body lives in constant mild jet lag. Sleep tends to turn shallower.

Your day counts too. From the moment you open your eyes, your need for sleep builds, and moving more helps.

What to do, evening and day

In the evening, take out what breaks it. Alcohol knocks you out sooner, then tends to break up the second half of the night, so one glass with dinner at most. Have your last coffee straight after lunch. An afternoon cup can cut deep sleep short even if you drop off fine. Keep dinner light and finish at least three hours before bed.

Bedroom between 18 and 20 degrees, and dark. To reach deep sleep your body needs to cool a little, and in a warm room it struggles. In the last hour, dim the lights and put screens away. Bright light tells your brain it's still daytime.

A fixed alarm, then ten minutes of daylight. Same time seven days a week, even after a late night. It usually matters more than when you fall asleep. Within an hour of waking, get outside, no sunglasses. Morning light shows your body clock the day has begun and helps set up that night's sleep.

Move during the day. People who exercise regularly tend to get more deep sleep and fall asleep sooner. Keep hard training away from bedtime, as it can raise adrenaline and temperature.

Start with the fixed alarm and morning light, and give them a few weeks before judging. Waking at 3am and eating late each have their own article.