Sleep, alcohol and smoking

Sleep, alcohol and smoking are daily habits, and each one touches your brain. Smoking and heavy drinking are two of the 14 risk factors that a large expert group linked to dementia in 2024.² Sleep was not on that list, but research suggests it matters too.

This page explains what is known about each habit, how strong the evidence is, and what you can do. The short version: get help to stop smoking, keep alcohol low, and take sleep problems to your doctor. None of these steps is a promise against dementia. They are good for your heart, mood and safety either way.

How much do these habits matter?

In 2024, the Lancet Commission, a large group of dementia experts, named 14 risk factors that can be changed. Together they may account for nearly half of dementia cases around the world.² Smoking and excessive alcohol use are two of the 14.² The other factors include high blood pressure, physical inactivity, diabetes and hearing loss.

The CDC also lists smoking and drinking too much among things that raise dementia risk.¹⁵ Heavy drinking can raise blood pressure and lead to brain injuries, which both harm the brain.¹⁵

Most of this evidence comes from studies that follow people over many years. These studies show links, not proof. Still, these habits also affect the heart and blood vessels, and what is good for the heart is usually good for the brain. See the full list of steps on our lower your risk chapter page.

Smoking and your brain

What the research shows

A review of 37 studies found that people who smoked in midlife were about 30% more likely to develop dementia than people who did not smoke.¹ Former smokers in that review did not have a higher risk.¹

A British study followed government workers for 32 years. People who still smoked had about a 36% higher risk of dementia. People who had quit had about the same risk as people who never smoked.¹

Smoking harms blood vessels everywhere in the body, including the brain. It also raises the risk of stroke, which is a common cause of vascular dementia. The CDC notes that quitting lowers other dementia risks too, such as stroke, high blood pressure and type 2 diabetes.¹⁵

Is it too late to quit?

No. Quitting helps your health no matter how old you are or how long you have smoked.¹² It can add as much as 10 years to your life.¹²

Here is what happens after you quit, according to the CDC:¹²

What about dementia after age 65? The research is less clear for older starters. In a study of nearly 790,000 adults in South Korea, people who quit had a lower dementia risk than people who kept smoking. The benefit was clearest in people who quit before age 65. Among people 65 and older, the study did not find a clear drop in dementia risk.¹

That does not mean quitting late is pointless. Your heart, lungs and stroke risk still improve.¹² Stroke and heart disease are themselves linked to memory problems. Studies may also need more years of follow-up to see the brain benefit in people who quit late.

Help to quit

Most people need more than willpower. Free coaching and quit medicines can help.¹³

In Virginia, Quit Now Virginia offers free, private counseling 24 hours a day by phone, text and chat. It is open to residents 13 and older. It also helps people who use vapes, e-cigarettes or smokeless tobacco. Interpreters are available in more than 140 languages.¹⁷

Alcohol and your brain

What the research shows

The Lancet Commission defines heavy drinking as more than 14 U.S. standard drinks a week in midlife.¹ One U.S. standard drink is about 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces of 80-proof liquor.⁹

In a study of more than 130,000 people in four European countries, heavy drinking in midlife was linked to about a 22% higher risk of dementia.¹ Drinking until you pass out was linked to higher risk, even in people who were not heavy drinkers overall.¹

Very heavy drinking over many years can also damage the brain directly. Read about alcohol-related brain damage, which can sometimes improve when a person stops drinking.

Is a little alcohol good for the brain?

Some studies found that light drinkers had less dementia than non-drinkers. Experts now doubt this. Many "non-drinkers" in those studies were former heavy drinkers who had quit because of poor health. That makes non-drinkers look less healthy than they are.^1,8

The Lancet Commission found no clear evidence that not drinking raises dementia risk.¹ The CDC says even moderate drinking may raise the risk of some cancers and other harms. Drinking less, or not at all, lowers health risks.⁸ The 2025–2030 Dietary Guidelines for Americans advise people to drink less alcohol for better overall health.¹⁰

If you do not drink, there is no reason to start. If you do drink, less is better.

Why alcohol is different in later life

As you age, the same drink can lead to a higher blood alcohol level. Older adults may feel alcohol's effects on balance, attention and driving more strongly.¹¹ Alcohol raises the risk of falls and other injuries.¹¹

Many older adults take medicines that mix badly with alcohol. These include sleep and anxiety medicines, opioid pain medicines, some cold and allergy medicines, and some blood pressure medicines. Some of these mixes can be deadly.¹¹ Ask your pharmacist about each medicine you take. Alcohol misuse in later life is also linked to faster loss of memory, thinking and judgment.¹¹

Read more on alcohol in later life.

If you find it hard to cut back, that is common, and help works. The SAMHSA National Helpline, 1-800-662-4357, is free, private and open 24/7. It can connect you to treatment near you.¹⁸

Sleep and your brain

What the research shows

The CDC recommends 7 to 9 hours of sleep for adults aged 61 to 64, and 7 to 8 hours for adults 65 and older.⁵

A British study followed nearly 8,000 people for about 25 years. People who slept 6 hours or less at age 50 or 60 had a higher risk of dementia later than people who slept 7 hours. People who had short sleep at ages 50, 60 and 70 had about a 30% higher risk.³

The authors were careful about what this means. Early brain changes from dementia can start years before memory loss and may themselves disturb sleep. So poor sleep could be an early sign, a cause, or both.³

Why sleep may matter

Sleep seems to help the brain clean up. In a small NIH study, 20 healthy adults stayed awake for one night. The next day, brain scans showed about 5% more amyloid (a sticky protein that builds up in Alzheimer's) in parts of the brain linked to memory.⁴ The study was small, and it did not show whether this short-term change leads to disease.⁴

Poor sleep also raises the risk of high blood pressure, heart disease, stroke and diabetes.¹⁹ Those conditions are linked to dementia.

Sleep apnea

Sleep apnea means your breathing stops and starts many times during sleep. Signs include loud snoring, gasping or choking at night, and feeling very sleepy during the day.⁶ Memory loss and trouble focusing can also be symptoms.⁷

Untreated sleep apnea raises the risk of stroke and heart attack.⁶ Researchers are still studying whether treating it lowers dementia risk. It is still worth treating because you may feel more alert and protect your heart.

A doctor can test for it with an overnight study in a sleep lab or a home sleep test. CPAP, a machine that gently blows air through a mask, is the main treatment for most people.⁷ Learn more on our sleep apnea page.

Insomnia and sleep medicines

Insomnia means trouble falling or staying asleep. A non-drug approach called CBT for insomnia (CBT-I) is a short program that retrains sleep habits. Our page explains how it works. See our pages on insomnia and sleep in later life.

Sleep aids, including ones sold without a prescription, have risks for older adults that are worth knowing. Read sleep medicines: what to know before you choose one. Never stop or change a prescribed medicine on your own. Talk with your doctor or pharmacist first.

When to get help

See your doctor if:

• You want to quit smoking or vaping and have not been able to on your own.
• You find it hard to cut back on alcohol, or you feel shaky or sick when you stop. Stopping heavy drinking suddenly can be dangerous, so do it with medical help.
• You snore loudly, gasp at night, or feel sleepy during the day.
• You have trouble sleeping most nights for weeks.
• You notice new memory problems. Sleep problems, alcohol and some medicines can all affect memory, and several causes can be treated. See treatable conditions that look like dementia.

I smoked for 40 years. Is the damage already done?

Not all of it. Your heart attack risk drops sharply within 1 to 2 years of quitting, and stroke risk goes down over 5 to 10 years.¹² In long studies, people who had quit did not have a higher dementia risk than people who never smoked.¹ It is never too late to try, and it often takes more than one attempt.

Should I have a glass of red wine for my brain?

There is no good evidence that starting to drink protects the brain.¹ Health agencies advise drinking less, not more.^8,10 If you do not drink now, there is no reason to start.

I sleep only 6 hours. Am I going to get dementia?

No one can say that from sleep alone. The link with short sleep is modest, and it is not proven to cause dementia.³ If you wake up rested and feel fine during the day, you may not need to worry. If you feel tired or have trouble sleeping, talk with your doctor.

Do vapes or e-cigarettes count?

Quit Now Virginia and other quitlines help people stop vaping and using e-cigarettes, not only cigarettes.¹⁷ Talk with your doctor about the best way to become fully nicotine-free.

For a daily plan that brings all the risk factors together, see keeping your brain healthy. You can also read about staying mentally and socially active and head injury and air pollution.

Education only. This page is general information written from the sources listed. It is not medical, legal or financial advice and does not replace a doctor, therapist or lawyer who knows your situation. How we write and check pages.