Brain fog. Fuzzy thinking. Call it what you will, but even the healthiest among us experience “senior moments” from time to time.

Age-related thinning of our neurons and synaptic connections may be the reason two-thirds of people experience some mental decline by age 40. One in eight people age 65 and older will eventually develop Alzheimer’s disease.

Here’s the good news: Your brain is not destined to break down permanently as you age.

“Until the last few years, the predominant view was that the brain matured in early life and became fixed, much like a computer,” says Michael Merzenich, PhD, a professor emeritus with the University of California, San Francisco, and a pioneer of the concept of neuroplasticity. “We now understand that the brain is continuously rewiring itself based on our experiences.”

The evolving brain

Not only can we form new wiring among existing brain cells, we can also grow new ones, says Florida neurologist David Perlmutter, MD, author of The Better Brain Book (Penguin, 2009). “We were always told you were given a finite number of brain cells and that it was a downhill slide as you aged. But, in fact, the human brain retains the ability to grow new brain cells throughout our lifetime.”

Science also shows that making smart diet and lifestyle choices, and sticking with them, can go a long way toward preserving—and even improving—cognitive function.

The first step is to regularly challenge your brain, says Paul D. Nussbaum, PhD, clinical neuropsychologist and adjunct professor of neurological surgery at the University of Pittsburgh School of Medicine.

“Your brain naturally wants information that is novel and complex,” says Nussbaum. Crosswords are fine, but if you’ve done them repeatedly, you’ve already developed those neuronal pathways, he cautions. Instead, “try something you stink at.” For example, take up an instrument if you’ve never played one before.

The next step is to incorporate these five daily strategies, shown in the latest research to boost brain power.

1. Get aerobic exercise

Recent animal studies have shown that aerobic workouts boost production of brain-derived neurotrophic factor (BDNF), a protein that helps neurons function better and fuels brain-cell growth. Aerobic exercise also makes neurons more resistant to injury.

And research on healthy adults shows that aerobic exercise not only improves attention and memory, but also reverses age-related brain shrinkage. “It’s possible that exercise improves blood pressure and energy metabolism, and thereby gets fuel to the brain more efficiently,” says Laura Baker, PhD, a brain researcher with the University of Washington School of Medicine.

In January, Baker published results from the first clinical trial looking at the impact of aerobic exercise on people diagnosed with pre-Alzheimer’s. Her team discovered that those who spent 45 to 60 minutes per day on a treadmill or stationary bike, four times a week for six months, improved their scores on tests of thinking speed, word recall, and ability to multitask.

Those who did stretching and balancing exercises instead saw no benefit. While the evidence is strongest for aerobic training, some research suggests strength training may also play a role in keeping the brain sharp: A recent study of 155 senior women in British Columbia indicated that those who lifted weights once or twice a week did up to 12 percent better in decision making, conflict resolution, memory tests, and multitasking a year later, while the control group saw their scores dip.

The key: Fit in a good workout at least twice a week, and stick with it.

2. Eat your fruits and veggies

Mounting evidence suggests that antioxidants present in colorful vegetables and dark-skinned fruits can fend off free radical damage in the brain and turn on genes that protect against inflammation, which has been shown to increase dementia risk.

An August 2009 study of 193 adults, ages 45 to 102, found that those with a high daily intake (about 400 grams) of fruits and vegetables did better, regardless of age, on cognitive tests than those who ate fewer than 100 grams per day. To see benefits, eat at least six servings of vegetables and two servings of fruit every day.

3. Take DHA

Perhaps the best researched nutrient for brain health, DHA (docosahexaenoic acid) is an omega-3 fatty acid abundant in oily fish, algae, and—not coincidentally—human breast milk. It’s believed to promote production of BDNF.

One 2009 study of 485 healthy adults found those who took 900 mg per day of DHA for six months made “significantly fewer errors” on memory tests than at the study’s onset. Perlmutter recommends supplementing with 300–800 mg per day, in addition to eating fish three times per week.

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4. Meditate

Stress boosts production of cortisol, a hormone that is particularly detrimental to cognitive function. Chronic anxiety is often tied to memory problems, says Nussbaum. One proven way to lower cortisol and boost brain cells is to meditate.

A 2009 study by neuroscientists at the UCLA School of Medicine used MRIs to examine the brains of 22 long-term meditators and 22 people who did not meditate. The meditators showed “significantly larger” gray matter in the right orbitofrontal cortex, the brain’s memory center, than the control group.

Learn how to meditate while at work

5. Rest up

Lack of sleep can also lead to a surge of cortisol and it inhibits the production of BDNF. On the flip side, sleep helps consolidate your memories, says Perlmutter. “The experiences you have during the course of the day are not really stored until you have adequate sleep.” Perlmutter recommends a minimum of eight hours a night.

Hot trend: Video games for your brain

Video games specially designed to challenge cognitive abilities (memory, spatial awareness, hand-eye coordination) and adapt over time, offer a technological boost for slack brains.

“The [games] are designed to tune into your brain performance level and carry you back to the way you processed information when you were younger,” says Michael Merzenich, PhD, a professor emeritus with the University of California, San Francisco, and co-founder of brain-game pioneer Posit Science.

Research is young and somewhat mixed. However, one 2009 Mayo Clinic study looked at 487 seniors, half of whom spent an hour a day, five days a week for eight weeks, using the Posit Science Brain Fitness Program. The other half read and watched educational videos.

The control group saw little change over time, but the Posit group improved speed on cognitive tests by about 60 percent.

The takeaway? These games certainly can’t hurt—just don’t substitute them for other brain-boosting diet and lifestyle habits.