Bad Habits That May Take a Toll on Brain Health

Bad habits take a toll

Candy Sagon

Updated August 19, 2022

A close up of a hand holding a cigarette and shot glass

Westend61/Getty Images

At my last annual wellness exam, my doctor chided me for the number of hours I sit at the computer versus the number of hours I spend exercising.

“All that sitting isn’t good for your brain,” she admonished. “Until we can clone brains, you need to take care of the one you have.”

Sigh. She’s right, of course. We all have bad habits, but some of them can really take a toll on our mental abilities.

Here are some of the worst things you can do for your brain health, according to experts.

1. Thinking about only the bad stuff.

Constantly dwelling on the negative may have a negative effect on your brain. A four-year study published in June 2020 in the journal Alzheimer’s and Dementia found that repetitive negative thinking in older adults — such as constantly worrying about the future and rehashing the past — was linked to more cognitive decline and increased build-up in the brain of two harmful proteins associated with Alzheimer’s disease.

While those among the 292 subjects who had depression and anxiety also were more likely to have cognitive decline, they did not have the amyloid or tau protein deposits, suggesting that repetitive negative thinking “may be a new risk factor for dementia,” lead study author and psychiatrist Natalie Marchant said in a statement.

To avoid constantly going over the same issues or problems and to calm the brain and reduce stress, quiet those thoughts by distracting yourself with music or reading, setting time limits, and practicing yoga or meditation, a report from the experts on AARP’s Global Council on Brain Health suggests.

2. Having a daily cocktail …or two or three.

The COVID-19 crisis has been a stressful time for everyone, to put it mildly, and the surge in alcohol sales and consumption is one indicator.

A September 2020 report in the journal JAMA Network Open found that 3 out of 4 Americans drank more than they did in 2019. They’re also reporting increases in the number of drinks they have and in alcohol-related problems, researchers found.

How much is too much? Heavy drinking is defined as more than four drinks on any day for men and more than three drinks for women, according to the National Institute on Alcohol Abuse and Alcoholism. Moderate drinking is defined as up to one drink per day for women and up to two drinks daily for men.

But even moderate drinking can take a toll on your brain. A June 2017 British study revealed that moderate drinking is associated with brain changes, including shrinkage in the brain’s hippocampus, a region that plays a major role in learning and memory.

Finding ways other than alcohol to deal with these stressful times is paramount to good brain health.

3. Curling into a tight ball of stress.

For a study published in September 2020 in the journal The Gerontologist, Brenda Whitehead, an associate professor of psychology at the University of Michigan-Dearborn, surveyed 825 adults, age 60 and older, about how they adjusted their lives during the early lockdown phase of the coronavirus pandemic. People were asked about their main sources of comfort/joy and of stress during that time.

“Faith stood out as an effective coping resource for older adults,” Whitehead told AARP in an email. “Those reporting some aspect of their faith, such as trust in God, prayer, online religious services, scripture reading, etc…, had significantly lower levels of perceived stress,” as well as lower levels of negative emotions and higher levels of positive feelings, she said.

Participants also reported that exercise, spending time outdoors appreciating nature, and some form of social support or interaction — whether by email, text or video chat — brought them more happiness and less stress during this difficult time.

Legal Disclaimer

Best Of

4. Severe sleep apnea.

Untreated severe sleep apnea — when your breathing repeatedly stops and starts — has been linked to brain changes and impaired thinking and memory.

Sleep apnea may also raise your risk of dementia, according to a November 2020 Australian study published in the Journal of Alzheimer’s Disease. Brain scans of study participants showed that those with severe sleep apnea had higher rates of a protein called beta-amyloid, which builds up on the walls of the arteries in the brain and may increase dementia risk.

But at least one study, published in September 2014 in the journal Sleep, found that white matter damage in the brain caused by severe sleep apnea may be reversible with treatment to improve breathing.

5. Drinking soda, including diet soda, every day.

Americans are hooked on sugar, and sweetened drinks are our primary source of the substance, according to government figures.

That’s bad news for our brain. Studies suggest that adults who consume more than two sugary drinks a day (including soda and other sweetened beverages) are more likely to have poorer memory, smaller brain volume, and other signs of accelerated brain aging and risk factors for early-stage Alzheimer’s disease.

And guzzling diet soda isn’t much better. A May 2017 study published in the journal Stroke determined that those who drank diet soda daily were at an increased risk for both stroke and dementia, compared with those who did not.

So do your brain a favor. Instead of soda, chose a beverage that’s not sweetened by either sugar or fake sugar. If you really miss the bubbles, check out the many unsweetened, flavored fizzy waters available.

6. Not doing anything to help others.

Lending a hand to others by volunteering not only helps the recipients; rather, there’s growing evidence it may have mental and physical health benefits for the doer.

A number of studies focusing on older adults found that volunteering was linked to a reduced risk of cognitive impairment, a lower risk of heart disease and a greater sense of well-being.

A March 2017 Swedish study of about 1,000 retired adults, published in the journal PLOS ONE, even discovered that regularly volunteering was linked to fewer complaints about memory lapses, problems concentrating and other so-called senior moments.

More evidence of the benefits of doing good: Harvard researchers, in a June 2020 study of nearly 13,000 adults older than 50, found that those who volunteered at least 100 hours a year (about two hours a week) had better mental health, including more optimism and a sense of purpose in life.

Published in the American Journal of Preventive Medicine, the study also revealed that volunteering was linked to a reduced risk of death and fewer feelings of hopelessness and loneliness.

Lead author Eric Kim, now an assistant professor of psychology at the University of British Columbia, said in an email that “volunteering is associated with many factors that help enhance mental health, such as more physical activity and connecting with social networks, as well as biological factors such as reduced inflammation.”

He noted that while the pandemic makes in-person volunteering risky, there still may be opportunities “in which we could all serve our communities [and] help ourselves,” as well.

7. Not drinking enough water.

Even mild dehydration can affect thinking, slowing down our ability to focus and make decisions, along with causing muscle pain, fatigue, dizziness and headache.

That’s because as we age, our bodies get less adept at regulating changes in body temperature and we also may lose our sense of thirst, according to a September 2020 study published in The Journal of Physiology. For this reason, some scientists say older adults may need to drink more water to compensate for these changes. In addition, a 2018 meta-analysis of 33 studies published in the journal of Medicine & Science in Sports & Exercise found that dehydration affects cognitive performance, especially for tasks involving attention and decision-making.

For older adults, some medicines may also cause the body to lose more water, which makes it even more important to take in enough fluids.

To help you remember to stay hydrated, the National Institute of Aging recommends not waiting to feel thirsty before drinking water or other fluids and taking pills with a full glass of water. If urinary control is a problem, don’t cut back on liquids; instead, talk with your doctor about treatment.

8. Too much sitting, not enough walking.

The catchy phrase “Sitting is the new smoking” was coined about a decade ago to describe research that linked an increased risk of death, similar to smoking, with sitting too much. Scientists urged us to stand up, move around and get more exercise to offset the effects of our sedentary lifestyle.

In the years since, a growing number of studies have shown that physical activity may help delay the onset of mental decline as we age and have other beneficial effects on brain structure.

A study published in November 2020 in the Journal of the American Geriatrics Society has some more good news: Making changes to diet and physical activity — even over a short period — may improve thinking skills and lower dementia risk.

The 119 adults in the study, who were older than 65 and had mild cognitive impairment, were randomized into two groups for eight weeks: a control group who received online information about a healthy diet and exercise and an intervention group who got the same information but also met with a dietitian and an exercise coach.

Over six months of follow-up, those in the intervention group had higher scores on mental-skills tests and lower risk factors for Alzheimer’s disease and dementia than did participants in the control group.

“We’ve known for some time that lifestyle changes such as these can reduce dementia risk in the general population. What this study adds is that with the right intervention, people experiencing cognitive decline may … [be able] to ‘bounce back’ from decline,” lead author Mitchell McMaster, a doctoral student at the Australian National University, said in a statement.

9. Continuing to smoke.

Smoking harms nearly every organ of the body, according to the National Institutes of Health, and that includes the brain. Published in June 2012, a British and French study of more than 7,200 adults, ages 44 to 69, found faster cognitive decline over 10 years in men who smoked than in nonsmokers or female smokers. Intermittent smokers and recent ex-smokers also experienced greater cognitive decline. The good news was that those who kicked the habit for 10 years scored just as well on mental-skills tests as did nonsmokers.

A more recent eight-year Korean study of more than 46,000 men age 60 and older, published in September 2018 in the Annals of Clinical and Translational Neurology, looked at the link between smoking cessation and a reduced risk of dementia. Participants were divided into four groups: continual smokers, short-term quitters (less than four years), long-term quitters (more than four years) and those who never smoked.

Compared with continual smokers, both long-term quitters and those who never smoked had a decreased risk of dementia. “Smoking should be understood as a risk factor for dementia,” researchers wrote, and “smokers should be encouraged to quit in order to reduce the risk.”

Learn more about the research in this article

• "Repetitive negative thinking is associated with amyloid, tau, and cognitive decline," Alzheimer's & Dementia, June 2020. This study looked at 292 people over the age of 55 who were part of the Pre-symptomatic Evaluation of Experimental or Novel Treatments for Alzheimer's Disease (PREVENT-AD) cohort and an additional 68 people who were part of the Multi-Modal Neuroimaging in Alzheimer’s Disease (IMAP+) cohort. All participants completed questionnaires about their repetitive negative thinking and moods; some also had brain scans and/or cognitive screening tests done. The researchers found that repetitive negative thinking was associated with cognitive decline. Because this is a population study, it shows a correlation but does not prove cause and effect. Read the full study.

• "Changes in Adult Alcohol Use and Consequences During the COVID-19 Pandemic in the US," JAMA Network Open, September 2020. In this study, researchers surveyed more than 1,500 adults about their alcohol consumption and found that 3 in 4 adults said they were drinking more frequently than they did in 2019. Women in particular also reported more heavy drinking and more alcohol-related problems compared to 2019. Limitations of the study include the fact that it relied on participants’ own reporting of their alcohol consumption. Read the full study.

• "Moderate alcohol consumption as risk factor for adverse brain outcomes and cognitive decline: longitudinal cohort study," BMJ, June 2017. In this observation cohort study, 550 men and women with a mean age of 43 reported their alcohol intake weekly and underwent regular cognitive screening tests over the course of 30 years. They also received brain scans. Researchers found that higher alcohol intake was associated with an increased risk of atrophy in the hippocampus. Even moderate drinkers were three times more likely to have hippocampal atrophy. Limitations of the study include the fact that it relied on participants’ own reporting of their alcohol consumption and that, as a population study, it shows a correlation but does not prove cause and effect. Read the full study.

• "Older Adults’ Experience of the COVID-19 Pandemic: A Mixed-Methods Analysis of Stresses and Joys," The Gerontologist, February 2021. Read the full study.

• "Severe Obstructive Sleep Apnea Is Associated with Higher Brain Amyloid Burden: A Preliminary PET Imaging Study," Journal of Alzheimer's Disease, November 2020. Read a summary of the study. (A fee is required to access the full study.)

• "White Matter Integrity in Obstructive Sleep Apnea before and after Treatment," Sleep, September 2014. This study followed 17 people with obstructive sleep apnea for 12 months as they received CPAP treatment. The participants underwent magnetic resonance imaging (MRI) and completed tests to assess their cognitive function. The researchers found that after a year of treatment, the participants had significant improvements in cognitive function as well as an almost complete reversal of white matter abnormalities in the brain. The study was funded by a CPAP manufacturer, and two of the study authors work for a CPAP manufacturer. Read the full study.

• "Sugary beverage intake and preclinical Alzheimer’s disease in the community," Alzheimer's & Dementia, March 2017. In this study of thousands of adults who were part of the Framingham Heart Study, participants filled out questionnaires about what they ate and drank, participated in cognitive testing and received brain MRIs. The researchers found that a higher intake of sugary beverages was associated with lower total brain volume and poorer performance on episodic memory tests. Limitations of the study include the fact that it relied on participants’ own reporting of their sugary beverage consumption and that, as a population study, it shows a correlation but does not prove cause and effect. Read a summary of the study. (A fee is required to access the full study.)

• "Sugar- and Artificially Sweetened Beverages and the Risks of Incident Stroke and Dementia," Stroke, April 2017. In this study of more than 4,000 adults who were part of the Framingham Heart Study Offspring cohort, researchers reviewed participants’ food and beverage intake questionnaires and checked for incidents of stroke and dementia. Researchers found an association between artificially sweetened soft drink consumption and an increased risk of stroke and dementia. Limitations of the study include the fact that it relied on participants’ own reporting of their soft drink consumption and that, as a population study, it shows a correlation but does not prove cause and effect. Read the full study.

• "Volunteering Is Associated with Lower Risk of Cognitive Impairment," Journal of the American Geriatrics Society, October 2016. This study looked at 13,262 people over age 60 who were part of the Health and Retirement Study (HRS), in which personal interviews were conducted every two years to assess cognitive function. The researchers found that volunteering later in life is associated with a lower risk of cognitive decline. As a population study, it shows a correlation but does not prove cause and effect. Read the full study.

• "Volunteering and Cardiovascular Disease Risk: Does Helping Others Get ‘Under the Skin?’" The Gerontologist, October 2016. This study looked at data from 7,803 adults who were part of the Health and Retirement Study (HRS). Researchers found that middle-aged volunteers were less likely to have metabolic syndrome as well as risk factors for cardiovascular disease such as elevated blood glucose levels and excess belly fat. As a population study, it shows a correlation but does not prove cause and effect. Read the full study.

• "Volunteer Work and Well-Being," Journal of Health and Social Behavior, June 2001. This study looked at data from 2,681 adults who were part of the Americans’ Changing Lives longitudinal study. Researchers found that volunteering was associated with an improvement in six aspects of personal well-being: happiness, life satisfaction, self-esteem, sense of control over life, physical health and depression. As a population study, it shows a correlation but does not prove cause and effect. Read the full study.

• "Can volunteering in later life reduce the risk of dementia? A 5-year longitudinal study among volunteering and non-volunteering retired seniors," PLoS One, March 2017. Read the full study.

• "Volunteering and Subsequent Health and Well-Being in Older Adults: An Outcome-Wide Longitudinal Approach," American Journal of Preventive Medicine, June 2020. Read a summary of the study. (A fee is required to access the full study.)

• "Ageing attenuates the effect of extracellular hyperosmolality on whole-body heat exchange during exercise-heat stress," The Journal of Physiology, September 2020. In this study of 10 young men (mean age of 25) and 10 middle-aged or older men (mean age of 61) who completed hour-long cycling workouts, researchers found that the older participants weren’t as efficient at regulating changes in body temperature during exercise. Read the full study.

• "Dehydration Impairs Cognitive Performance: A Meta-analysis," Medicine & Science in Sports & Exercise, November 2018. Read the full study.

• "Physical Activity, Cognition, and Brain Outcomes: A Review of the 2018 Physical Activity Guidelines," Medicine & Science in Sports & Exercise, June 2019. This review of research, conducted in part for the 2018 Health and Human Services Physical Activity Guidelines for Americans Advisory Committee, looked at systematic reviews, meta-analyses and pooled analyses. Researchers found an association between moderate- to vigorous-intensity physical activity and better cognitive function. Read the full study.

• "Lifestyle Risk Factors and Cognitive Outcomes from the Multidomain Dementia Risk Reduction Randomized Controlled Trial, Body Brain Life for Cognitive Decline (BBL-CD)," Journal of the American Geriatrics Society, November 2020. Read a summary of the study. (A fee is required to access the full study.)

• "Impact of smoking on cognitive decline in early old age: the Whitehall II cohort study," Archives of General Psychiatry, June 2012. Read the full study.

• "Effect of smoking cessation on the risk of dementia: a longitudinal study," Annals of Clinical and Translational Neurology, September 2018. Read the full study.