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Research Shows Lockdowns Changed Your Body Chemistry

Updated: Oct 11, 2022

Even before COVID-19 circled the globe, another plague was quietly threatening public health: loneliness.

Chances are you’ve experienced loneliness at some point in your life. Most people have it’s part of being human. But more than that, social connections have been declining for decades. In 2017, U.S. Surgeon General Vivek Murthy sounded the alarms, calling it a public-health “epidemic.” Yet a 2019 Cigna survey still found that as much as 61% of Americans felt alone.

Then, the pandemic hit. Lockdowns forced loneliness into the spotlight as “self-isolation” and “social distancing” entered common vocabulary. And the effects on mental health were profound. Researchers found that depression symptoms, for example, were three times higher during lockdown than before.

But isolation impacts physical health too. In fact, as recent studies point out, loneliness puts your body into flight-or-fight-or-freeze mode. And that increased stress response creates a cascade effect. Loneliness has been associated with a higher risk of coronary heart disease, high blood pressure, dementia and premature death.

In this article, we’ll take a look at the science behind loneliness. We’ll explain what it is, how it affects your body and how you can help manage it.

What is Loneliness?

Although loneliness is a universal experience, it’s a subjective one. Some people can feel isolated while in a party full of people. Others thrive off of their solitary time, only realizing after days or weeks that they crave long chats with a loved one.

Ultimately, the definition of loneliness comes down to you: It’s the difference between the social relationships you want and those you feel you have. That’s why solitude isn’t synonymous with loneliness. You can be alone for long stretches, yet satisfied with your social connections. But when you feel rejected, abandoned or involuntarily isolated … loneliness enters the picture.

Suddenly, the connections you crave are, seemingly, no longer attainable. Your body reacts because humans are social creatures. We rely on cooperation to not only survive but thrive as a species. It’s how we build families, societies and civilizations.

Isolation is a threat to that stability. It’s why ostracism has been such an effective punishment for centuries. So loneliness can be interpreted as a biological signal, alerting us of a threat to our survival.

How Loneliness Hurts Your Health

When humans feel threatened, either mentally or physically, we call that stress. Stress is a complicated biological process, but it essentially flips your body’s natural alarm system, AKA the fight-or-flight-or-freeze response, into “on” mode. This signals your adrenal glands to flood more cortisol (the stress hormone) into your bloodstream.

In quick surges, cortisol is useful. It can raise your blood sugar, giving you a boost of energy to handle a stressor. It can help you focus, react and even cement memories.

However, when threats seemingly persist, your body’s alarm system can get stuck in “on” mode. That chronic stress can cause cortisol imbalances … and suddenly, a system meant to protect you can cause damage instead. Cue stress-related health issues, such as hypertension, heart disease and more.

Here’s where loneliness comes in. Since loneliness can be seen as a form of stress, researchers have studied the relationship between it and cortisol, the stress hormone.

In one 2021 study, they found that greater loneliness was linked to higher levels of cortisol at waking and a blunted cortisol awakening response (CAR) in early adolescents. In another 2029 meta-analysis, analysts studied 40 years of research and found that loneliness was linked to biological factors such as circulating stress hormones.

Interestingly, researchers also found that cortisol surges may help lonely people reconnect. In one study, lonely individuals reported fewer friendships, yet named more friends as time went on, suggesting loneliness may serve as an impetus to form more necessary connections. Results also showed lonely individuals with higher cortisol befriended less lonely individuals instead of those who were lonelier. This could mean cortisol helps create bonds that could better fulfill a sense of social belonging.

Ultimately, though, it’s clear that long-term loneliness can present notable health risks. In fact, according to the work of Julianne Holt-Lunstad, professor of psychology and neuroscience at Brigham Young University, loneliness has the same impact on mortality as alcoholism or smoking 15 cigarettes a day. So it’s important to address this stressor.

(Editor’s Note: If you’re feeling a little overwhelmed by stress, you can start getting in control by testing and managing your cortisol levels in real time. Read how here.)

Quick Tips for Managing Loneliness and Stress

If you’re lonely, almost the last thing you want to do is reach out.

However, research shows that your relationships (even if not face-to-face) can lower your stress levels, increase feelings of social support and boost overall mood.

Reach out to someone you trust: Think about the relationships in your life that bring you peace. Maybe it’s a family member, a trusted friend or a coworker. Often these relationships calm us because we know what to expect from them. They bring a sense of stability. It’s why studies show that you feel more in control, and your cortisol levels remain lower, when your social status feels stable. Leaning into these relationships can strengthen your bonds and help you reconnect with your social support.

Join a social group (online or in person): Another study proves that social support can be just as effective as yoga for lowering overall stress. A group of prenatally depressed women were split into a yoga group and a social support group. Both met weekly for 12 weeks. At the end of each session, both groups saw lower cortisol levels. By joining a group, you can form new social connections and help manage your stress.

Talk about it: Last, but not least, it’s important to acknowledge your stress and talk to someone about it. In fact, in one study, cognitive behavioral therapy for stress management directly reduced cortisol levels in a group of pregnant women. Consider online therapy, which allows you to reach out to a therapist whenever works best for you.

Ultimately, remember that a large part of stress relief is acknowledging the main cause and reaching out. Recognize that loneliness is your body’s way of telling you it’s time to reconnect in whatever way you value.

Before you go, we have one more question for you: How can we get better? Here at, our goal is to gather the best information to help you understand the science of stress. If you think we missed anything in our research, please let us know.


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