The 9 Worst Habits for Your Brain

2. You skip your vaccines

It’s estimated that more than half of Americans blew off the flu shot during the 2021 flu season, and we know that today many people are hesitant about keeping up with COVID-19 boosters. But opting out of vaccinations may be a missed opportunity in the fight against dementia.

A recent nationwide study of adults over 65 found that people who received at least one influenza vaccination were 40 percent less likely to develop Alzheimer’s disease, according to research conducted by Paul Schulz, M.D., a neurologist at McGovern Medical School at the University of Texas Health Science Center in Houston, and colleagues. Other researchers have found that people ages 65 to 75 who had received the pneumonia vaccination had a 25 to 30 percent reduction in their chance of developing Alzheimer’s.

3. You drink sugary beverages

If your usual breakfast includes a tall glass of orange juice, take note. A 2017 study associated sugary beverage consumption with poorer episodic memory as well as lower total brain volume and hippocampal volume. And 2022 research found that sugar-sweetened beverages like soft drinks, sweetened tea, fruit drinks, sports drinks and energy drinks were all significantly linked to declined cognitive function.

“Even though fruit juice retains some beneficial phytonutrients, it’s primarily a sugary drink without the benefit of fiber,” says Annie Fenn, M.D., the founder of Brain Health Kitchen, a cooking school and community for Alzheimer’s prevention. Consuming sugary drinks may lead to spiking blood sugar and an exaggerated insulin response in many people, which, she says, may trigger chronic inflammation in the brain.

It may be far better to eat whole fruits, not drink their juices. “A small orange provides 2.5 grams of fiber to balance its 9 grams of sugar,” Fenn explains. “When you consume the equivalent amount of orange juice, the fiber has been strained out.”

4. You have unhealthy sleep habits

Quality sleep is crucial to a sharp and productive mind, according to the Global Council on Brain Health.

Consistency is one important marker of good quality sleep: Go to bed and wake up at the same time every day. Shift work, changing time zones, chronic stress and too much caffeine or alcohol can all throw off your rhythm. So, too, can sleeping in a room that’s not cool or dark enough. And if you have symptoms of sleep apnea, such as snoring or daytime sleepiness, see a doctor.

"Abnormalities in oxygen level can be damaging to nerve cells by causing inflammation and amyloid plaque formation in the brain,” says Alon Avidan, M.D., director of the Sleep Disorders Center at the University of California, Los Angeles. Over time, he adds, “untreated sleep apnea accelerates memory and cognitive disturbances due to extensive buildup of brain amyloid, a key marker for Alzheimer’s disease.”

5. You crank up your headphones

If it’s bad for your ears, it could very well be bad for your brain. In a study of 639 adults ages 36 to 90, mild hearing loss was associated with a nearly twofold likelihood of dementia.

As a rule, if someone else can hear sound from your earbuds, they’re too loud, says Nicholas Reed, assistant professor at the Johns Hopkins Bloomberg School of Public Health. He also recommends carrying a pair of foam earplugs with you and using them at concerts or sporting events, and removing yourself from loud environments when possible.

“If you are standing within 3 feet of someone and you can’t hear them, the world around you is too loud,” he says.

6. You regularly take this type of medicine

A wide array of drugs — including tricyclic antidepressants, some overactive bladder medications and some over-the-counter antihistamines — can block the actions of acetylcholine, a brain chemical important for learning and memory. A study found that a higher cumulative use of these drugs was associated with increased incidence of dementia.

If you regularly take a drug in one of these categories, don’t panic, says Yuko Hara, director of aging and Alzheimer’s prevention at the Alzheimer's Drug Discovery Foundation. But if you regularly take a number of these, it makes sense to ask your doctor about the risk of anticholinergics and to discuss whether you should explore alternate medications or other options.

7. You don’t have a sense of purpose

Bosses, kids, spouses — when we’re younger, it seems like everyone is relying on us. But when we get older, freedom from those responsibilities can have a darker side.

“Having a reason to get up in the morning, knowing that people are depending upon you, feeling that you are making important contributions can contribute to healthy aging,” explains Scott Kaiser, M.D., director of Geriatric Cognitive Health at the Pacific Neuroscience Institute.

Researchers at the Rush Alzheimer’s Disease Center in Chicago found an association in people who scored high on a purpose-in-life assessment: They were approximately 2.4 times more likely to remain Alzheimer’s-free than those with low scores.

If you’re feeling a distinct lack of purpose, do your brain a huge favor by embracing some new responsibilities, says Carla Marie Manly, a clinical psychologist in Santa Rosa, California. “Find a new opportunity by using the time and energy not spent on child-rearing or working to get a pet, explore a passion project, volunteer or travel,” she says.

8. You’re not a fan of flossing

Do you roll your eyes when your dentist tells you to floss? You may want to give it a whirl. “Poor oral hygiene can lead to the buildup of bacteria in the mouth, leading to inflammation of the gums [gingivitis], which if left untreated can lead to a chronic infection called periodontitis,” says Hara. A 2022 study found that poor periodontal health and tooth loss appear to increase the risk of both cognitive decline and dementia. 

“Bacteria and the inflammatory mediators can make their way from the mouth into the bloodstream and into the brain,” says Hara. Additional research found that people missing many teeth have a 48 percent higher risk of cognitive impairment and a 28 percent higher risk of dementia.

The American Dental Association recommends brushing your teeth twice per day with a fluoride toothpaste for two minutes per session, flossing daily, limiting sugary beverages and snacks, and keeping up with dentist appointments.

9. You have a few drinks per week

Even light to moderate drinking can cause reduced brain volume, according to a 2022 study by the University of Pennsylvania. The researchers found that half a beer per day was enough to trigger these changes — and that the link grew stronger the greater the level of alcohol consumption.

So, a 50-year-old who went from one drink a day to two experienced associated changes in the brain equivalent to aging two years. And increasing from two to three drinks at that age was like aging the brain by three and a half years.

“Alcohol interferes with brain functions such as speech, memory, judgment and balance, making it more difficult to think clearly and move appropriately,” says Hara. Over time, this may be detrimental to brain health.

“Cutting back on alcohol is a smart strategy for brain health,” adds Fenn. She suggests trying not to reach for alcohol when you are “sad, mad, tired or bored,” scheduling some “dry days” into your weeks, trying out mocktail recipes and measuring your drinks so that you know how much you are consuming. “One glass of wine, for example, is 5 ounces, considerably less than the typical pour,” she explains.