How To Stay Mentally Sharp -- for Life, Part I
Alzheimers prevention
Perhaps you've heard that the typical adult loses some 10,000 brain cells a day. The implication is that by the time we qualify for Social Security, there's not much left between our ears.
On the contrary: The brain contains hundreds of billions of neurons, giving us reasoning and memory capabilities that in many ways dwarf the most sophisticated supercomputer. While it's true that from age 20 to 70 the brain loses about 10% of its mass (according to Stanley Rapoport, M.D., chief of the neuroscience laboratory at the National Institute on Aging in Bethesda, Md.), by and large, what's left compensates for what's lost. The aging brain, says psychologist and New York Times writer Daniel Goleman, Ph.D., is like a veteran baseball pitcher. His fast ball isn't quite as speedy as it was during his rookie season, but he's become wily enough to strike out batters with other pitches.
Here's how to make the most of your gray matter -- for life:
- If you're a woman, consider postmenopausal hormone replacement therapy. Women may be at greater risk for Alzheimer's than men, but they can do more to prevent and treat it. Specifically, they can take estrogen. Several studies show that women who take estrogen after menopause have an unexpectedly low rate of Alzheimer's disease. Among women with Alzheimer's, those taking estrogen suffer less severe symptoms and slower mental deterioration.
Estrogen boosts the production of acetylcholine, a key chemical (neurotransmitter) involved in the transmission of nerve impulses across the tiny gaps between nerve cells (synapses). Estrogen also impedes the deposition of beta-amyloid, the protein involved in the characteristic plaques of Alzheimer's disease. In addition, estrogen improves blood flow through the brain, and enhances verbal abilities of postmenopausal women who take hormone replacement therapy. Estrogen also helps maintain the integrity of the hippocampus, an area of the brain involved in memory.
In one notable study, New York City researchers investigated risk of Alzheimer's among 1,124 elderly women. During the follow-up period, 14.9% of them developed Alzheimer's disease. Among women who had never used estrogen, the figure was 16.3%, while only 5.8% of estrogen users developed Alzheimer's. Among estrogen users, risk decreased with hormone use for longer than one year.
A study by National Institute on Aging (NIA) researchers corroborates these findings. As part of the 38-year Baltimore Longitudinal Study of Aging, the NIA group assessed 16 years' worth of medical records for 514 postmenopausal women. They found that compared with women who had never taken estrogen, those who had were 54% less likely to develop Alzheimer's disease.
Estrogen also helps prevent osteoporosis, which plays a role in the lead poisoning of elderly women.
- Pay attention. This fundamental memory aid is often forgotten. "Focus, focus, focus," says Douglas Herrmann, Ph.D., a memory researcher at the National Center for Health Statistics in Washington, D.C., and author of the book Super Memory. "If information doesn't register in your brain in the first place, you have no chance of remembering it." When receiving information you want to recall, drop whatever else you're doing and pay attention to it.
- Repeat names out loud. One of the most annoying -- and embarrassing -- memory lapses is forgetting people's names. Try this old salesman's trick: When you first meet someone, repeat the person's name out loud several times. Repetition and vocalization help cement it in the mind. Greet the person by name: "Hello, Ms. Smith." You might also ask the person to spell the names: "Is that S-m-i-t-h or S-m-y-t-h-e?" Repeat the name in conversation: "Enjoying the party, Ms. Smith?" Repeat the name as you take your leave: "Nice meeting you, Ms. Smith." Afterward, repeat the name aloud a few more times, or write it down.
- Get organized. Life is too complicated to recall everything most people must remember: appointments, birthdays, errands, financial details, etc. Write things down on calendars and/or datebooks. Keep these items handy, and coordinated. Consult them frequently.
- Control your blood pressure. Alzheimer's may be the leading cause of senile dementia, but the second leading cause of mental impairment in old age is multi-infarct dementia (MID). MID results from mini-strokes known as transient ischemic attacks (TIAs), which involve brief periods of spacing out. Most TIAs last less than a minute, and people appear to recover fully from them. But after a few TIAs, MID sets in because of cumulative stroke-like damage to the brain. The best way to prevent MID is to prevent stroke and TIAs. The key risk factor for stroke is high blood pressure. Keep yours under control.
Here's another reason your brain will thank you for controlling your blood pressure: Back in the mid-1960s, University of Hawaii researchers measured the blood pressure of 4,700 Japanese-American men whose average age at the time was 48. Thirty years later, they gave cognitive function tests to 3,800 survivors, average age 78. Even when they did not suffer strokes or TIAs, the higher their midlife systolic blood pressure (the first number in a blood pressure reading), the poorer their mental abilities three decades later. High blood pressure injures the small blood vessels in the brain, contributing to mental impairment.
- Take an aspirin a day. In addition to keeping blood pressure under control, another way to prevent stroke and MID is to take low-dose aspirin (one-half to one tablet a day). Many studies show that it reduces risk of stroke, and in one study, it actually reversed MID.
Low-dose aspirin also helps prevent heart attack, and the memory loss associated with recovery from a medical emergency closely related to heart attack: cardiac arrest when the heart stops beating. Recent advances in emergency medical care have improved the odds of surviving cardiac arrest. But the downside of survival is memory loss. Today's treatments can often start the heart up again, but they cannot compensate for the fact that during the arrest, the brain's oxygen supply is interrupted.
A recent Scottish study identified 35 survivors of cardiac arrest, and compared them with 35 age- and sex-matched heart attack survivors who did not suffer cardiac arrest. Both groups had the same immediate recall -- repeating a phone number immediately after hearing it. But the cardiac arrest survivors had significantly more difficulty with longer-term memory.
A good deal of research suggests that regular use of such nonsteroidal anti-inflammatory drugs (NSAIDs) as ibuprofen (Motrin, Advil, Nuprin), naproxen (Aleve, Naprosyn, Anaprox), indomethacin (Indocin), and meclofenamate (Meclomen), helps prevent Alzheimer's disease.
Powerful evidence of NSAID benefits comes from the 38-year Baltimore Longitudinal Study of Aging. Researchers from the National Institute on Aging assessed NSAID use in 1,828 older people, 110 of whom developed Alzheimer's from 1980 to 1995. Every two years, all subjects filled out extensive food and drug surveys, and were given a battery of cognition and memory tests. People who took NSAIDs more than occasionally for at least two years were 30% to 60% less likely to develop Alzheimer's disease. As duration of NSAID use increased, Alzheimer's risk decreased.
Among the NSAIDs studied, aspirin had only a weak Alzheimer's-preventive effect, one that did not reach statistical significance -- but there was a clear trend toward lower risk with more-than-occasional aspirin use.
The main problem with NSAIDs is that they carry a significant risk of stomach distress, and gastrointestinal bleeding, which can become serious.
- Get regular exercise. This is standard good-health advice. In addition to helping prevent heart disease, many cancers, obesity, diabetes, and high blood pressure (hypertension), it also helps keep the mind sharp. Scientists at the Neuropsychology Research Laboratory at the Veterans Affairs Medical Center in Salt Lake City gave identical mental function tests to men in their 20s and 60s. Overall, the younger men had quicker mental reaction times. But when the researchers ranked the older men in order of their physical fitness, those in the best shape were as quick-witted as the young men. Physical activity increases blood flow through the brain and helps fine-tune the neurons that control mental acuity.
- Lead an intellectually active life. Several studies have linked education to a reduced risk of mental impairment in the elderly. The theory is that education exercises the brain, increasing the number of neural pathways so that if any get damaged later in life, others compensate. But formal education is not the whole story. People who lead mentally active lives -- traveling, reading books, taking courses, doing puzzles, and pursuing hobbies and new experiences -- maintain intellectual acuity better than those who spend their lives vegetating in front of the TV.
- Don't smoke anything. Tobacco smoke constricts the blood vessels, including those in the brain. That means less blood flow to brain cells, with less oxygen, and fewer nutrients going upstairs. Smoking also pumps a great deal of carbon monoxide into the blood. Carbon monoxide displaces oxygen, impairing brain cells even more.
Marijuana also impairs mental acuity. Harvard researchers gave a battery of mental-function tests to two groups of college students. One group said they smoked marijuana daily. The other smoked it no more than once a month. Both groups lived at the research center for a day before the testing, and did not use marijuana during that time. But even after the period of abstinence, the heavy smokers performed significantly more poorly on the tests, suggesting that marijuana causes persistent mental impairment.
- Watch the alcohol. Alcohol is the third leading cause of mental decline in old age. More than half of alcoholics show evidence of cerebral atrophy, and even social drinkers who rarely get drunk can suffer mental impairment, because as people grow older, their sensitivity to alcohol's harmful effects increases.
However, this is not to say that everyone should quit drinking. Alcoholics should, but for most other people, moderate alcohol consumption (up to two drinks a day) helps prevent heart attack, the leading cause of death in the U.S. And a recent study shows that light alcohol consumption may actually improve intellectual abilities in elderly people. Researchers at the Indiana University School of Medicine surveyed 2,040 African-Americans, average age 74, about their lifestyle, including their drinking habits, and then gave them cognitive-ability tests. Those who had 10 or more drinks per week had an average score of 29.93. Those who had four to 10 drinks a week scored higher, 30.18. Abstainers scored even higher, 30.42. But light drinkers, those who had up to four drinks a week but no more, scored highest -- 30.93.
It's not clear why light drinking should improve cognition. One possibility is that people in the best health feel free to drink a little, while those who have medical problems -- including problems that subtly affect cognition -- might feel compelled to abstain. Another possibility is that moderate alcohol use's ability to increase HDL (so-called good cholesterol) -- the mechanism by which it helps prevent heart attack -- might also in some way improve cognition.
But remember: Any more than a drink or two a day, and over the long term, you're risking your intellectual health.
- Watch the drugs. Compared with Alzheimer's disease, which accounts for 50% to 60% of dementia, drug-related dementia accounts for only an estimated 5% of cognitive deterioration. ] But the middle-aged and elderly population numbers in the tens of millions, and 5% of it is an enormous number of people.
As people grow older, they tend to take more medications. By themselves, most meditations do not cause cognitive impairment. But when people take several drugs simultaneously (polypharmacy) -- as many elderly people do -- significant cognitive problems may emerge that mimic Alzheimer's disease: memory loss, absent-mindedness, confusion, disorientation, and emotional outbursts. Alcohol use aggravates drug-related dementia (see above).
In addition, as people grow older, they tend to become more sensitive to drug effects. An appropriate dose for a 45-year-old may be too much for a 75-year-old. Doctors should adjust drug dosages depending on people's ages, but some neglect to do this, inadvertently prescribing overdoses that may cause cognitive impairment.
If you develop any memory or reasoning problems, make a list of all the medications you take -- both prescription and over-the-counter, plus your alcohol consumption. Show the list to your physician and pharmacist, and ask if your combination of medications might impair cognition. Mental acuity returns with removal of the offending drug(s). Of course, you may not be able to discontinue use of some medications. But dose adjustments and drug substitutions may help.
Some drugs that may cause cognitive impairment include: antihistamines, certain blood pressure medications (beta-blockers and calcium-channel blockers), tranquilizers, sedatives, and narcotics.
- Get enough sleep. Sleep needs vary, but according to William Dement, M.D., Ph.D., director of the Stanford Sleep Disorders Clinic and chair of the National Commission on Sleep Disorders Research, most people need at least seven hours a night to function well. Any less, and they develop a "sleep debt" that interferes with memory, judgment, and reaction time, increasing absent-mindedness and risk of accidents. If you ever find yourself dozing off after lunch or at movies, plays, or concerts, Dement says you need more sleep.
- Prevent and treat obstructive sleep apnea. Apnea means lack of breathing. Obstructive sleep apnea is a particularly hazardous type of snoring -- loud and punctuated by choking silences when breathing actually stops. It wreaks havoc with sleep quality, raises blood pressure, increases risk of heart attack, and causes daytime drowsiness and -- according to recent studies -- cognitive impairment.
French scientists at the National Institute of Health and Medical Research in Paris evaluated 1,400 men and women, aged 60 to 70, using the Mini-Mental Status Exam and seven other tests of cognitive function. The participants also completed a questionnaire that asked about snoring, daytime drowsiness, and sleep apnea. Those who admitted having sleep apnea or who appeared to have it scored poorest in the cognitive tests, with daytime sleepiness being the best predictor of poor mental ability.
In an accompanying editorial, D.L. Bliwise of the Sleep Disorders Center at Emory University Medical Center in Atlanta noted that dementia and daytime sleepiness often go hand in hand. He speculated that aggressive treatment of sleep apnea may help treat dementia.
About 10% of middle-aged men have obstructive sleep apnea, particularly those who are overweight. But about 90% of people with apnea are undiagnosed, according to William Dement, M.D.
The best ways to prevent sleep apnea include weight loss and drinking less alcohol.
If you suspect sleep apnea, the condition is easy to treat. All it takes is a continuous positive airway pressure (C-PAP) machine. C-PAP devices include a mask that fits over the nose connected to a small pump that gently pushes extra oxygen into the lungs with each breath. C-PAPs prevent airway collapse and maintain a healthy level of oxygen in the blood. They cost about $1,200 and are available from sleep centers.