In the past several weeks, I’ve completely blanked on the title of a book I’d just finished reading as well as on the name of an old college friend. I’ve also been known to forget the whereabouts of my house keys on a regular basis.

I’m only in my mid-30s. If I can’t remember this stuff now, what chance do I have in my 60s and beyond?

Memory lapses can be aggravating, frustrating and even embarrassing. I also find them slightly nerve-racking, given that I have watched several relatives and family friends struggle with Alzheimer’s disease. But the truth is that occasional memory blips in your 30s — and even 40s and 50s — rarely signal a serious problem, says Susan Lehmann ­of the Geriatric Psychiatry Clinic at Johns Hopkins Hospital.

“It’s typically more about distraction and how much information the human brain can handle at one time,” she says. “All the complexities of life make it easy, in any one day, to forget something.” In other words, if you’re distracted by a screaming child or bills or a nearby television while you’re reading a novel, you’re probably not making memories properly and thus may have difficulty recalling characters, plot twists and other details.

Though I do forget things here and there, I probably haven’t yet begun the process of normal cognitive decline that typically kicks in during the mid-40s, says neurologist Jeffrey Cummings, director of the Cleveland Clinic’s Lou Ruvo Center for Brain Health. “The most reliable observation about memory in the course of getting older is the slowing of the identification of specific bits of information — like trying to recall a person’s name when you meet them in unexpected circumstances and there’s only three seconds where it’s socially appropriate to say, ‘Hello, Bill,’ and you just can’t get there in time,” he says.

Even if you’re young, don’t fret about forgetting things. (Getty Images)

“Older people can concentrate just as long as younger ones without distraction, but it usually takes a bit longer to process and absorb a task, and [they] also have a little bit more difficulty in switching tasks and multi-tasking,” adds Lehmann.

Those of us who do forget a phone number or an appointment here or there aren’t necessarily doomed to more serious cognitive impairment later on. “Though they make people anxious, the normal memory changes that happen as you age through midlife and beyond — which tend to be episodic, occasional and stable — are not a risk factor for Alzheimer’s disease or dementia,” says Lehmann. “The difference between normal memory loss with aging and something that’s concerning has to do with frequency and persistence, and how much it starts to interfere with everyday life and your ability to function and work.”

Indeed, Lehmann stresses that cognitive decline isn’t an inevitable part of aging: “There is a lot of variability among people.” A study published last month in the journal Lancet Neurology summarized evidence from hundreds of studies and found that up to half of all Alzheimer’s cases are associated with seven modifiable risk factors, including midlife obesity, depression and cognitive inactivity or low educational attainment.

While it remains unclear whether Alzheimer’s can be prevented, experts believe that most of us have at least some control over our long-term brain health. “You can’t stop aging, you can’t change your family history or genetics, but you can make some basic lifestyle choices that may help with age-related cognitive decline and also more serious problems,” says neurologist Scott Turner, director of the Memory Disorders Program at Georgetown University Medical Center. He recommends an integrated wellness approach that includes a Mediterranean diet that’s high in antioxidants, regular exercise and keeping your mind engaged and challenged, whether it’s with crossword puzzles or more formal study.

“The earlier you start doing these things, the better,” says Turner. As the Lancet research points out, it’s also important to prevent or treat vascular risk factors such as high blood pressure, diabetes and smoking. “The kinds of health conditions that predispose somebody to heart attack and stroke increase risk for dementia, too,” says Lehmann.

I don’t know about you, but I plan to start working on my brain health straight away — before I forget!

keep your brain working

In the interest of having as many resources at your disposal as possible, clinical psychologist Cynthia Green, author of “30 Days to

Total Brain Health,” offers these tips for staving off memory loss:

● Play games against the clock. Instead of just regular old brain games, try timed mental challenges, which target the skills most affected by aging, such as being able to think quickly and to multi-task. Computer games and apps that claim to promote brain fitness can be fun and helpful, but they haven’t been proven to be better than similar activities, so start with a clocked board game such as Boggle, which prompts you to pay attention and work fast.

● Learn how to remember. Research has shown that targeted cognitive training can help people better absorb such information as names and passwords — and retain it longer. That’s true for even basic memory-boosting strategies such as repeating material as you’re learning it. Also, tools including organizers and to-do lists can help you keep track of things you need to know to function effectively but don’t truly have to memorize, such as appointments, errands and directions.

● Seek social connections. Studies suggest that people who engage with family, friends and others on a regular basis can significantly reduce their risk of memory loss and other cognitive impairments. These social ties provide not only intangible emotional benefits but also a forum to work on the intellectual skills that often are challenged by aging; for example, keeping up a conversation requires concentration, thinking on your feet and being nimble with your neurons.

● Develop a purpose. Last year, researchers from Rush University Medical Center in Chicago reported that older people with a positive attitude and a greater sense of purpose in life had a lower risk of developing Alzheimer’s disease and mild cognitive impairment and a slower rate of cognitive decline than people with lesser motivation.