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Loneliness, Toxic Relationships and Health

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When we talk about the pillars of health we usually refer to diet , exercise and rest , but we tend to leave aside the way we relate to each other .

However, personal relationships have a profound impact on our health and longevity.

You will understand the concept of Dunbar’s number, how loneliness atrophies the brain, and how toxic relationships harm us.

Dunbar’s number.

Relating to others seems natural to us, which is why we are not aware of its great complexity. The simple act of having a conversation activates a multitude of brain areas.

We must interpret both the other person’s words and discern their emotions from body language. At the same time, we must prepare our response and adjust our own non-verbal language.

The complexity of socialization multiplies as group size increases. Living in a group implies keeping a kind of social accounting with all its members.

We must remember the favors we owe, or are owed to us, the commitments made and the degree of reliability of each member. We also need to maintain a mental map of the changing social hierarchy, understanding the relationships between different people.

It is also important to adapt our behavior when interacting with each subject, according to their particularities, our shared history and the knowledge we have about their own relationships and interests.

Loneliness, Toxic Relationships and Health.

Living with others involves reaching consensus and collaborating on multiple projects. This great complexity is precisely what limited group size in ancestral societies.

Anthropologist Robin Dunbar discovered that there was a direct correlation between the volume of each species’ neocortex and the size of its social group.

In the case of humans, he concluded that the maximum number of social ties our brain can manage without becoming overwhelmed is approximately 150, the famous Dunbar number .

Recent studies confirm this hypothesis, observing that the density of gray matter in areas of the brain related to social perception is related to the number of people with whom we interact.(1)

Loneliness atrophies the brain.

Interacting with others requires great mental ability.

Studies in rats indicate that those that live with others in the cage develop larger hippocampi than those that are raised alone.

On the other hand, when rats that have always lived with others are deprived of company, in a few months they suffer a reduction in their brain volume.(2)

For obvious reasons we cannot replicate these experiments in humans. In fact, solitary confinement is considered the worst punishment in prisons, and for many it is a form of torture.

However, we have natural experiments that confirm a similar effect of social isolation in humans.

One study, for example, analyzed the brains of eight researchers before spending months at a scientific station in Antarctica.

When they returned, their seahorses had shrunk by 7%, and that’s considering they weren’t completely alone. As your social group drastically reduced, so did your brain .

Other factors, such as spending more time indoors and the monotony of the Arctic environment, likely played a role.

In summary, the great complexity of social interaction turns it into a powerful neuronal lubricant , which when reduced accelerates mental decline.

Loneliness increases stress.

Social isolation damages our health in a multitude of ways. To begin with, the brain interprets loneliness as an immediate danger, increasing stress. In a wild environment, loneliness was a death sentence.


One study asked participants to indicate how isolated they felt at different times of the day. In addition to recording this information, they had to take a saliva sample.(3)

When the researchers evaluated the results, they observed that the level of cortisol in saliva showed a strong correlation with episodes of loneliness .

One of the effects of stress is to inhibit the immune system, which would explain why loneliness contributes to illness.

The feeling of loneliness also fragments sleep and increases nighttime wakefulness, because it was dangerous for our brain to sleep alone.

The effect of toxic relationships.

Social interaction is a double-edged sword. It is responsible for the greatest joys in our lives, but also for the most stressful moments.

Starting with the good, the quality of our relationships is the best predictor of the perception of happiness , in addition to being a great emotional buffer.

According to a large Harvard study , the people most satisfied with their personal relationships at age 50 are the healthiest at age 80.(4)

Connection with others enhances the good and mitigates the bad. If you search through your memories, surely the best moments were shared experiences.

On the other hand, toxic relationships harm all areas of our health .

People who report poorer quality of their close relationships suffer higher rates of illness over the following years.

Troubled marriages increase blood pressure in both partners. Additionally, their inflammatory cytokines appear elevated and their wounds take longer to heal.

Conflictive interpersonal relationships also increase the risk of depression.

As they say, better alone than in bad company.

Loneliness vs. Social isolation.

Social isolation is an objective metric, relative to the number of interactions we have with others. Loneliness, however, is a subjective experience. Social isolation can be measured, loneliness can only be felt. They are obviously related. Social isolation tends to increase the feeling of loneliness, but the levels that each person requires to avoid feeling alone are different (depending, for example, on your place on the introvert-extrovert spectrum).

Childhood experiences also determine the degree of social connection that each person considers ideal.

Although the relationship is stronger with loneliness, social isolation is also associated with greater cognitive decline. Even if you’re not aware, your brain benefits from interacting with others.

Loneliness not only has to do with the number of social relationships we maintain, but also with the meaning we give them. We can feel lonely in the crowd if we do not share something we appreciate with others.

+4 Sources

Freaktofit has strict sourcing guidelines and relies on peer-reviewed studies, educational research institutes, and medical organizations. We avoid using tertiary references. You can learn more about how we ensure our content is accurate and up-to-date by reading our editorial policy.

  1. Social brain volume is associated with in-degree social network size among older adults;
  2. Modification of hippocampal neurogenesis and neuroplasticity by social environments;
  3. Loneliness and cortisol: momentary, day-to-day, and trait associations;
  4. li>Good genes are nice, but joy is better;

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