What loneliness does to your brain — and your stroke risk
05/14/2025
How being alone changes your brain — and what you can do to protect it and your overall health.
By Paul Wright, MD, Senior Vice President and System Chair of the Nuvance Health Neuroscience Institute, part of Northwell Health
We’ve all felt lonely at some point. But when being alone becomes a long-term experience — not just a momentary feeling — it can have serious effects on your health. In fact, loneliness may impact your brain as deeply as stress, sleep deprivation or even trauma.
Recent research shows chronic loneliness doesn’t just hurt emotionally — it alters brain function, increases inflammation and raises the risk for stroke, dementia and other neurological conditions.
Understanding how loneliness affects the brain is an important way you can protect your long-term brain health.
What happens in the brain when you’re lonely?
According to neuroscientists, loneliness activates a threat response in the brain. This heightened state of alert can make people feel anxious, distrustful or emotionally numb — even when they’re around others.
The neuroscience of loneliness
Studies reveal changes in the default mode network — the brain’s “idle” mode tied to self-reflection and rumination when someone experiences chronic loneliness. When you’re chronically lonely, this network becomes overactive, leading to more negative thoughts and withdrawal.
The amygdala, a region involved in processing fear and danger, becomes more reactive. That means your brain sees being alone as a potential threat.
Dopamine and oxytocin — the chemicals that support motivation, bonding and trust — can become dysregulated, making it harder to connect, even when the opportunity arises.
In short, loneliness can rewire your brain in ways that make it harder to seek connection — trapping people in a harmful cycle.
Related content: Stressed out? Discover the effect of stress on the brain and ways to manage it.
The link between being alone and stroke risk
You may be surprised to learn chronic loneliness is a risk factor for stroke and other common diseases. A recent report by the U.S. Surgeon General called loneliness an epidemic, linking it to:
- 32% increased risk of stroke
- 29% increased risk of heart disease
- Higher levels of inflammation and stress hormones
- Greater likelihood of high blood pressure, depression and sleep problems
Related content: Stroke 101 and why it’s critical to call 911 for symptoms
How can being alone cause negative changes in the brain?
When your brain senses social isolation, it sends signals to your body that keep it in a low-grade stress response. Over time, this increases wear and tear on your blood vessels, immune system and brain — making you more vulnerable to stroke and other chronic illnesses.
Related content: How to achieve physical, mental and emotional wellness for better overall health
How being alone can affect cognitive health
Beyond stroke, long-term loneliness can increase your risk for:
- Memory decline
- Brain fog
- Dementia and Alzheimer’s disease
That’s because social interaction acts like a workout for the brain. It stimulates thinking, communication, empathy and emotion regulation — all essential for cognitive health.
When you’re frequently alone, these brain functions aren’t getting exercised, leading to faster cognitive decline over time.
Related content: How clutter affects your brain health
Signs your brain might be feeling lonely
You don’t have to be physically alone to feel lonely. Some signs your brain is affected by social isolation include:
- Feeling emotionally detached, even around family and friends
- Increased anxiety or overthinking
- Trouble sleeping or focusing
- Lack of motivation or pleasure in everyday activities
- Feeling “numb” or easily overwhelmed
If this sounds familiar, you’re not alone — and there’s good news. The brain can rebuild connection patterns through small, consistent changes.
Related content: What happens in your brain when you give and practice gratitude?
How to rewire the lonely brain
The brain’s ability to adapt — called neuroplasticity — means that even after long periods of loneliness, it can learn to connect again. Here’s how:
Stimulate your brain’s social networks
- Call or text a friend — even short interactions help.
- Join a group based on a shared hobby or interest.
- Volunteering or offering to help someone activates reward centers in the brain.
- Practice active listening to re-engage empathy pathways.
Support brain health overall
- Get regular exercise, which boosts brain chemicals like dopamine and serotonin.
- Prioritize sleep, which helps regulate emotion and cognitive function.
- Consider talk therapy to challenge negative thinking and rebuild trust.
- Try mindfulness or meditation, which can improve the brain’s ability to focus and connect.
Even spending time with a pet, or practicing kindness with strangers, can spark brain changes that reduce the impact of being alone.
Learn more in this video: The surprising effects of loneliness on your brain
Can remote connection help reduce loneliness?
With so many of our relationships happening through screens these days, it’s natural to wonder: Can digital interactions really help us feel less alone?
The answer is yes — with balance.
Video chats, texts and phone calls can support mental well-being — especially when they help maintain meaningful relationships.
But the brain still craves in-person cues like eye contact, touch, body language and synchronized movement, which trigger emotional bonding and release key neurochemicals like oxytocin and dopamine.
In-person connection uses more of your senses — you don’t just hear someone’s voice or see their face. You also experience:
- Touch, like a hug or handshake, which boosts oxytocin (the bonding hormone).
- Smell, which is tied to memory and emotional recall.
- Sight, including body language, facial expressions and eye contact.
- Movement, such as walking together, which activates motor and coordination centers in the brain.
This multi-sensory stimulation helps the brain feel fully engaged and socially connected. It also makes the moment more memorable, strengthening long-term recall and emotional bonds.
Relying only on digital connection may leave the brain in a semi-isolated state — feeling alone even while “connected.”
The takeaway?
Remote connection is a helpful tool — especially for busy schedules, long-distance relationships or mobility challenges. But, if possible, complement screen time with real-world interactions, even if it’s just a short conversation at the grocery store or waving to a neighbor.
Small moments of human connection — even brief and casual — can help rewire your brain’s sense of safety, belonging and trust.
Related content: The neuroscience and health benefits of experiencing awe and wonder
The bottom line: Loneliness doesn’t just affect your mood — it changes how your brain works. Being alone long-term increases your risk for stroke, memory decline and serious health issues. But with consistent effort, the brain can adapt, rewire and reconnect. If you’re feeling disconnected, small steps can be effective — not just for your mental health, but for your brain and body, too.