She’s hardly alone. These small, everyday moments – misplacing your keys, losing your train of thought, forgetting a name or why you walked upstairs – are almost universal by midlife. They’re also anxiety-provoking, especially with growing awareness of Alzheimer’s disease and other forms of dementia.

The reassuring news is that many memory lapses have surprisingly ordinary explanations. Before assuming the worst, experts say it’s worth considering several common – and often reversible – causes.

Normal age-related memory changes

Some slower thinking and trouble with recall is simply part of getting older.

“I tend to tell my patients in their 60s and 70s that, unfortunately, your brain is not functioning at the same level as it used to,” said Nathaniel Chin, geriatrician and medical director of the Wisconsin Alzheimer’s Disease Research Centre. “If those symptoms are subtle and occasional and you’re still functioning well overall, there’s a good chance that what you’re noticing isn’t something pathologic,” he said.

If you’re still managing your finances, keeping appointments and navigating familiar places, occasional forgetfulness that’s only a little bothersome is much less concerning than memory problems that interfere with everyday life, said Chin.

Are you forgetful, or just distracted?

Often what we call forgetfulness isn’t a memory issue at all: it’s an attention problem.

Modern life constantly divides our focus between work, family, caregiving responsibilities and an endless mental to-do list. Add to that nonstop interruptions from device notifications and alerts. This can make it difficult for our brains to process and retain information effectively.

That’s because memories have to be encoded before they can be retrieved, explained Nina Vasan, clinical assistant professor of psychiatry at Stanford University and the founder and director of Brainstorm: The Stanford Lab for Mental Health Innovation.

When you’re distracted, “the memory never gets written down,” she said. “Then you go hunting for something that was never saved properly and you decide your memory is the problem.”

The connection between poor sleep and memory

Another important thing to consider is how well you’re sleeping. During sleep, the brain consolidates short-term memories into long-term ones. Research suggests even one night of fewer than six hours of sleep can impair memory formation.

People in their 60s and 70s tend to have more disrupted sleep and get up more often during the night, said Brian J. Balin, professor of neuroscience and neuropathology and director of the Centre for Chronic Disorders of Ageing at Philadelphia College of Osteopathic Medicine. But there are plenty of reasons middle-aged adults, especially those with children and busy, stressful jobs both inside and outside the home, may not be sleeping well either, he said.

Studies suggest that chronic sleep deprivation and sleep disorders such as insomnia and untreated sleep apnoea can all interfere with the memory-cementing process, making it harder to learn, concentrate, pay attention and remember information.

Health issues can affect memory, too

Hormonal changes during perimenopause and menopause are one important example. The hippocampus and prefrontal cortex – brain regions involved in memory and executive function – contain large numbers of oestrogen receptors. As oestrogen levels decline, women often notice slower thinking and more frequent word-finding problems, said Vasan.

Menopause can also affect mood, which influences how efficiently the brain processes and retrieves information, said Ted Huey, associate director of Brown’s Centre for Alzheimer’s Disease Research and director of the Memory and Ageing Program at Butler Hospital.

Other conditions that could interfere with memory include ADHD, depression, untreated hearing loss, thyroid disorders and vitamin B12 deficiency. Drug side effects can also play a role.

When to see a doctor about forgetfulness

How do you know when forgetfulness has crossed the line into something more serious? Chin said he looks for three things:

Experts are also interested in what you’re forgetting. There’s a difference between losing your train of thought mid-conversation and forgetting the entire conversation happened, which is more serious.

Even if you’re feeling reassured that some forgetfulness isn’t a red flag, Huey still encourages people to mention any concerns to their healthcare provider – especially when it happens alongside sudden or extreme changes in your vision, sleep or executive function, or a new psychiatric illness such as a depression diagnosis for the first time. “Neurodegenerative diseases can present with symptoms other than memory, too,” Huey said.

A doctor can run some tests to separate out normal ageing issues from dementia, and a third category called mild cognitive impairment, or MCI, which sits between the two and describes when a person has cognitive issues but can still function day-to-day. MCI is affected by lots of things from your thyroid to sleep apnea, said Chin. Some people with MCI may go on to develop dementia, but some may not. “So it’s a very good stage to identify and treat people,” said Chin. “It’s a huge opportunity for lifestyle interventions.”

Research suggests that even modest lifestyle interventions – such as regular exercise, a MIND-style diet, health monitoring, cognitive challenges and social engagement – can improve brain health.

Getting help with any sleep concerns and treatment for mental health issues can also go a long way. “Untreated depression can look a lot like dementia,” Vasan said. “And if you need hearing aids, please get them.” One study showed the devices cut the risk of cognitive decline in high-risk older adults by almost 50%.

Chin also suggested taking steps to reduce stress with doing mentally stimulating activities to help “firm the networks of your brain”. You don’t have to learn a new language or instrument, he said. “You could do puzzles, word games or play cards with friends.”

There are some new Alzheimer’s drugs that show promise, but you’re only eligible for them in the earliest stages of the disease, said Huey. Too often, he said, he sees patients when they’re missing appointments and getting lost. By then, it’s too late for those medications.

Garfinkel has already incorporated many of the above habits into her life. She exercises five days a week, has a mostly healthy diet and knits every day, deliberately choosing patterns that teach her new techniques. Every evening she winds down with a word game.

Each year, her doctor gives her a five-word recall test. This is the first year she’s gotten one wrong. Her doctor isn’t concerned and ultimately neither is Garfinkel – for now. She’s doing what she can to keep her brain healthy, and accepting that occasionally walking into a room and forgetting why may just be a part of getting older.