How Does Loneliness Impact Our Bodies?

Over the past decade, loneliness has emerged as the next serious public health issue that researchers are trying to address. With the COVID-19 pandemic, health issues associated with loneliness have only increased. While loneliness is something everyone has experienced at least once, it can be difficult to articulate. Loneliness is defined as what someone experiences when they have fewer social relationships than they want. Loneliness has been described as a signal of an innate human need, like hunger or thirst.¹ While shelter, safety, food, and water are all basic needs that come to mind, connection with other humans is another important necessity that people have. Humans have always lived in groups from hunter-gatherer tribes, to ancient civilizations, to modern-day societies. When we had to fight for survival, this made sense. If we were alone, we struggled to gather food, protect ourselves, and stay warm. But what happens when we’re alone now? We can have food, shelter, and warmth all on our own – so what are the downsides?

Loneliness has been found to primarily impact two age groups: young adults ages 18 through 29 and older adults ages 65 through 79.¹ In young adults, oversleeping/undersleeping, increased risk of depression, and increased risk of cardiovascular disease are all associated with having long-term feelings of loneliness.² More common causes of loneliness in this age range are life changes such as starting a job, going to university, or moving away from home. For older adults, loneliness can arise from losing a partner or family member, residing in assisted living communities/facilities, or increased financial difficulties.¹ However, older adults experience different effects from loneliness than young adults do. They are more likely to undergo pathological brain changes, resulting in cognitive decline, Alzheimer’s, and/or dementia.² So, while people of all ages can experience loneliness, different age groups tend to feel the effects differently.

Scientists have studied the consequences of loneliness on the body to understand why and how these changes occur. Overall, increased loneliness is associated with a higher risk of mortality. For this to happen, though, there have to be changes within the body happening. The two main areas of focus for researchers have been mental health and physical health. There have been studies published on how loneliness impacts anxiety, depression, cardiovascular disease, and even diabetes. Research has only picked up since the COVID-19 pandemic and will likely proceed as we continue to feel the lasting effects of prolonged social isolation.³

As mentioned before, mental health can be significantly impacted by feeling lonely, specifically when considering depression and anxiety. Before discussing how depression and loneliness interact, it’s important to understand how scientists define depression: depressive episodes are identified by consistent low moods, irritability, restlessness, and intense hopelessness. In addition, people with depression may experience “sickness behaviors”, which include fatigue, reduced food and drink intake, and social withdrawal. Depression and loneliness commonly occur alongside each other, but recently it’s been found that loneliness can predict depression. Researchers believe that because loneliness may lead to a person having a negative self-image of themselves and withdrawing from their support group, loneliness may play a role in the onset of depression. In addition, loneliness is a known risk factor for social anxiety. Anxiety – a mental health condition associated with feelings of worry, uneasiness, and apprehension – is also commonly seen alongside loneliness. Social anxiety has been studied in adolescents, specifically within school settings, and how peer rejection impacts their mental health. Feeling victimized and unaccepted can lead to social distress, withdrawal, and thus loneliness. Both depression and anxiety can arise from prolonged feelings of loneliness, and it’s important to continue to research due to it impacting such a young age group.³

Loneliness also has a powerful impact on physical health. The relationship between cardiovascular health and feeling lonely is well-established.² Chronic loneliness can lead to neuroendocrine changes in the body alongside hypertension, which lead to cardiovascular disease. Cardiovascular disease, or heart disease, increases your chances of a heart attack or stroke. In addition to heart disease, recent research has shown that there are inflammatory responses that occur as a result of loneliness, similar to the “sickness behaviors” those with depression exhibit. While they are meant to protect your body, they are often unhelpful in the long run. Finally, loneliness can lead to people turning to unhealthy coping mechanisms including smoking, unhealthy eating, alcohol, or drugs. These activities can lead to diabetes, migraines, and again cardiovascular disease. So, not only can loneliness directly impact your physical health, but it can also indirectly harm you through other means.³

The pandemic has confirmed for us that no one is immune to feelings of loneliness, regardless of age or situation. From young adults who commonly use social media, to senior citizens who live in assisted living communities, anyone can feel lonely. Prolonged loneliness can have harmful effects, both mentally and physically.


  1. Lim, M. H., Eres, R., & Vasan, S. (2020). Understanding loneliness in the twenty-first century: an update on correlates, risk factors, and potential solutions. Social psychiatry and psychiatric epidemiology, 55(7), 793-810.
  2. Bhatti, A. B., & Haq, A. U. (2017). The Pathophysiology of Perceived Social Isolation: Effects on Health and Mortality. Cureus, 9(1).
  3. Quadt, L., Esposito, G., Critchley, H. D., & Garfinkel, S. N. (2020). Brain-body interactions underlying the association of loneliness with mental and physical health. Neuroscience & Biobehavioral Reviews, 116, 283-300.