The Impact of Chronic Stress on Brain Health

Most of us think of stress as something we feel—tight shoulders, a racing mind, trouble sleeping. But what many people don’t realize is that chronic stress can actually change the physical structure of the brain. Over time, these changes can affect memory, focus, decision-making, and even increase the risk of cognitive decline and dementia.

Preventive Neurology specialist Hollie Hristov, FNP, explains, “If not effectively managed over time, chronic stress, anxiety, and depression can cause changes in brain size—structural changes.” These changes impact not only how we think and feel day to day but also our long-term brain health.

Chronic Stress Physically Changes the Brain

“Chronic stress could actually decrease the size of the hippocampus, which is the memory center of the brain,” says Hristov. “It can also affect the prefrontal cortex, which can impact things like executive function, decision-making abilities, emotional regulation.”

These areas of the brain are essential for staying sharp, managing emotions, and remembering important details. As they shrink or lose function, you may find it harder to focus, stay organized, or control your mood.

Cortisol and Its Long-Term Impact

One of the main drivers behind these changes is cortisol, the body’s primary stress hormone. “Over time, those levels can actually raise and stay consistently high,” Hristov explains. “This actually can reduce the body's ability to handle stressful situations over time and also decrease hippocampal size as well.”

Chronic stress doesn’t stop with structural changes. “Poorly managed stress can impact neurochemicals in the brain—dopamine, serotonin—all those things that really impact mood,” says Hristov. As these chemicals become imbalanced, people are more likely to experience anxiety, depression, and emotional swings.

How Stress Affects the Whole Body

The effects of stress aren’t limited to the brain. “It can really impact sleep, pretty greatly,” Hristov points out. Poor sleep is directly linked to cognitive decline, as it affects the brain’s ability to clear out toxins and consolidate memories.

Stress also increases the risk for cardiovascular disease and metabolic disorders, which can further raise the risk of dementia. “It affects neuroplasticity,” Hristov explains, “so the brain’s ability to form new neural connections, which over time can impact the brain’s ability to adapt.”

Signs Stress Is Affecting Your Brain

Wondering if chronic stress is already taking a toll on your brain? According to Hristov, these are some of the early warning signs to watch for:

• Feeling mentally foggy
• Difficulty focusing on tasks
• Poor concentration
• Slower thinking or processing speed
• Trouble remembering appointments or recent conversations
• Lack of motivation
• Persistent fatigue
• Feeling overwhelmed by simple, everyday tasks (like doing the dishes or laundry)

Steps You Can Take to Support Your Brain

The good news is, you have the ability to make changes that support your brain health. “When you’re feeling those things, you just really want to be mindful,” Hristov advises. “That’s when you really want to try to grab the wheel and divert, because that’s when you can make big changes.”

Tracking cortisol levels over time can also provide helpful insights. “Cortisol can be beneficial to track over time,” she says. While a single fasting cortisol test isn’t always the best indicator, Hristov encourages patients to ask their doctors about monitoring trends. “Asking to track your cortisol over time would be helpful, and I think it’s a good gauge. It’s not perfect, but it’s a good gauge to see if that stress is really impacting your body function.”

Stress Looks Different at Every Life Stage

Stress is a constant throughout life, but the sources often change. “I feel like every stage of life comes with its own challenges and stressors,” says Hristov.

“Mid-thirties is stressful because you’re usually starting your career, kicking off life, trying to earn money. Your forties, you’re probably raising kids, which can be stressful. You’re planning for retirement. You’re probably growing in your career. Fifties, you go through hormonal changes—menopause, andropause—all those things.”

No matter the decade, Hristov emphasizes that it’s essential to find ways to manage stress that work for you. “Learning what ways to manage that stress, for you specifically, is really, really key,” she says.

The Takeaway

Stress isn’t just a passing feeling—it can have serious and lasting effects on the brain and body. Left unmanaged, it can accelerate cognitive decline and increase the risk of serious conditions like dementia.

But there’s hope. Recognizing the signs early and taking steps to manage stress can make a meaningful difference. Whether it’s through mindfulness, exercise, better sleep, or tracking your stress hormones, small actions can help protect your brain now and in the future.

To learn more about the impact of chronic stress on brain health, watch our conversation with Hollie Hristov, FNP, in the video above.

By Alicia J. Barber, PhD