How sleep affects concentration is simple to sum up: when you don't get enough, focusing gets harder. Sleep loss slows your reactions, makes mistakes more likely, and makes it harder to learn and make decisions. Most adults need at least 7 hours a night, and short nights add up.
Health agencies agree on the basics. The National Institute of Neurological Disorders and Stroke (NINDS) says lack of sleep makes it harder to concentrate and respond quickly. The National Heart, Lung, and Blood Institute (NHLBI) says sleep deficiency can cause problems with learning, focusing and reacting. Without enough sleep, the NHLBI says, you may:
Have trouble making decisions, solving problems and remembering things
Take longer to finish tasks
Have a slower reaction time
Make more mistakes
The flip side is encouraging. The NHLBI says a good night's sleep improves learning and problem-solving skills, and that sleep helps you pay attention, make decisions and be creative. The CDC says getting enough sleep can help you improve your attention and memory to better perform daily activities.
Sleep also matters for learning. NINDS explains that without sleep, you can't form or maintain the pathways in your brain that let you learn and create new memories.
You don't have to pull an all-nighter for sleep loss to affect your focus. In a well-known 2003 lab study of 48 healthy adults aged 21 to 38, some volunteers were limited to 4, 6 or 8 hours in bed per night for 14 days in a row, while others went 3 nights without sleep.
Those limited to 4 or 6 hours showed deficits on all the thinking tasks tested, and the deficits built up day after day. The researchers concluded that 6 hours or less a night produced deficits equivalent to up to 2 nights of no sleep at all. Yet the volunteers' ratings of their own sleepiness rose only a little after the first days, and the researchers concluded they were largely unaware of their growing deficits.
The practical lesson: feeling fine on short sleep doesn't mean your focus is fine.
The CDC recommends these amounts by age:
Adults 18 to 60: 7 or more hours
Adults 61 to 64: 7 to 9 hours
Adults 65 and older: 7 to 8 hours
Teens 13 to 17: 8 to 10 hours
Children 6 to 12: 9 to 12 hours
NINDS adds that most adults need 7 to 9 hours of sleep a night, even older people. For more detail, see our sister site's guide to how much sleep you need.
These tips come from the CDC and NINDS:
Keep a steady schedule. Go to bed and get up at the same time every day.
Make your room work for sleep. The CDC suggests keeping it quiet, relaxing and at a cool temperature. NINDS suggests avoiding bright lights and loud sounds.
Turn off devices at least 30 minutes before bedtime. NINDS suggests not watching TV or using a smartphone or computer in your bedroom.
Watch the caffeine. The CDC suggests avoiding it in the afternoon or evening. NINDS also advises avoiding nicotine late in the day.
Skip large meals and alcohol before bedtime.
Exercise regularly. NINDS suggests at least 30 minutes most days, but not within a few hours of bedtime.
Wind down. Try a warm bath, reading or another relaxing routine.
Don't lie in bed awake. If you can't get to sleep, NINDS suggests doing something else, like reading or listening to calming music, until you feel tired.
For a checklist version, see the sleep hygiene checklist on our sister site, and if coffee is part of your day, our guide to caffeine and sleep.
Sometimes a bad night happens anyway. A few ways to protect your focus and your safety:
Don't drive drowsy. The NHLBI says studies show sleep deficiency harms your driving ability as much as or more than being drunk.
Double-check important work. Sleep loss makes mistakes more likely, so build in a second look.
Break big tasks into smaller pieces and tackle one at a time.
Go easy on late caffeine, so tonight's sleep isn't affected too.
Return to your usual schedule that night, since the CDC recommends going to bed and getting up at the same time every day.
NINDS advises seeing a doctor if you have problems sleeping or if you feel unusually tired during the day. The NHS suggests seeing a GP if changing your sleeping habits hasn't helped, if you've had trouble sleeping for months, or if poor sleep is affecting your daily life in a way that makes it hard to cope. If trouble concentrating continues even when you sleep well, mention that too.
This is general information, not medical advice. Talk to your doctor or pharmacist about your own situation.
Yes. NINDS says lack of sleep makes it harder to concentrate and respond quickly, and the NHS lists finding it difficult to concentrate during the day among the signs of insomnia.
The CDC recommends 7 or more hours for adults 18 to 60, 7 to 9 for ages 61 to 64, and 7 to 8 for 65 and older. Teens 13 to 17 need 8 to 10.
Not always. In a 2003 lab study, people limited to 6 hours or less for two weeks had growing deficits but rated themselves only a little sleepier, and the researchers concluded they were largely unaware of the decline.
It can be dangerous. The NHLBI says sleep deficiency harms your driving ability as much as or more than being drunk. If you feel drowsy, don't drive.
Attention Age: Focus Test is an entertainment and self-practice app, not a medical, clinical or diagnostic test, and it can't tell you whether you're getting enough sleep. It runs a five-minute test of three timed tasks with a 0 to 100 Attention Index, and a weekly re-test that uses the same tasks and scoring, labeling changes under 5 points as "about the same." No account is needed, results stay on your iPhone and there are no ads.
Get Attention Age free on the App Store
Brain Basics: Understanding Sleep (National Institute of Neurological Disorders and Stroke)
Sleep Deprivation and Deficiency: How Sleep Affects Your Health (NHLBI, NIH)
The cumulative cost of additional wakefulness (Sleep, via PubMed)