• Loneliness, itself, won't weaken the immune system, but loneliness is often associated with chronic stress and inflammation that could impair immune function.
• Research has found that it's the perception of loneliness, not necessarily the physical separation from people, that can trigger a stress response and have a negative impact on health.
• To feel less lonely, consider limiting your time on social media and spend more time devising activities you can do with friends and colleagues like virtual book clubs and hang out video chats.

If you're feeling alone and sick, the two may be more connected than you think. Social isolation can impact our physical and mental health, and even affect our immune systems.

However, there's a difference between social isolation and loneliness - and there are ways to feel less lonely even while socially isolated. Here's what you need to know.

Chronic loneliness may weaken the immune system

Loneliness can make your immune system less robust, says Soma Mandal, MD, an internist. "People who are lonelier tend to have more stress," she says. Loneliness-induced stress can activate the adrenocortical system, also known as the "fight or flight" response. While that response is useful in the case of a real threat, it can become harmful when it's continually activated over time.

"Chronic loneliness can lead to deterioration in our ability to respond to potential infections as well as the strength of our immune response," says Chirag Shah, MD, an emergency physician.

For example, a pair of 2013 studies found that lonelier adults had more inflammation in response to stress. Although the studies only had 134 and 144 participants respectively, they confirm other animal studies that found a link between loneliness and inflammation, Mandal says.

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Inflammation is a response to bodily harm - white blood cells move to an injured area, which can cause swelling or redness. Like the fight or flight response, inflammation is useful when it's needed, but when it occurs over time it can have a negative impact on health.

"Chronic inflammation such as this can lead to other illnesses such as heart disease, cancer, and dementia. It can also affect the immune system's ability to fight off viral infections," Mandal explains. There's still much to be determined about how exactly loneliness impacts health, and more large-scale research is necessary. However, it's clear that loneliness is associated with more stress and inflammation, which are connected to negative health outcomes.

"While larger, more robust studies need to be done, these studies continue to build on the theory that loneliness activates the stress response inappropriately," Shah says.

How to feel less lonely during social isolation

It's important to recognize that loneliness and social isolation aren't the same thing.

"Social isolation is the objective physical separation of people, such as living alone; loneliness is the subjective distressed feeling of being alone or separated," Mandal says.

Research has found it's your perception of loneliness - not an objective measurement of your social interaction - that affects your health. For example, a 2017 study found that people who perceived themselves as lonely had more cold symptoms than people who didn't feel lonely.

So, during social isolation, it's important to do what you can to decrease your feelings of loneliness, even when you're stuck at home. You can still diminish your psychological state of distress - including loneliness - while respecting social distancing guidelines, Shah says.

For example, a 2019 study found that having access to simple technology like a radio, television, or tablet decreased feelings of loneliness for study participants, more than half of whom had reported experiencing poor mental health. A 2016 study of 591 older adults found that social technology use, including Skype and Facebook, reduced feelings of loneliness. However, for younger people, social media has a more complicated relationship to loneliness. A 2018 study of 143 undergraduate students found that participants who limited their use of Facebook, Instagram, and Snapchat to 30 minutes a day experienced less loneliness than those who had unlimited social media use.

During social distancing, technology is most effective when it's used to interact directly with others, Mandal says. Talking over video chat, doing a workout together virtually, or participating in a virtual book club will likely do more to combat loneliness than just posting or scrolling on social media.

"There are so many things we can do to help other people and we can still remain safe in our own living rooms," she says. For more resources on how to mitigate stress and feel less lonely, read our article, "How to deal with anxiety and loneliness during the coronavirus outbreak."

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