Loneliness is proven to have a detrimental effect on your body and wellbeing. It can lead to high blood pressure, cardiovascular disease, reduced immunity, and depression — loneliness was even declared a public health issue.

In order to keep yourself as healthy as possible, maintaining relationships with your family and friends is key — there's a reason that "Social" is a need in "The Sims."

However, even if you don't feel like you're lonely, keep an eye out for these seemingly benign signs of loneliness: your body could be trying to tell you something.

You constantly feel tired.

A study published in 2011 linked loneliness to sleep fragmentation, which is defined as "arousals and awakenings that disrupt the normal stages and architecture of sleep." In other words, it's when you can't sleep through the night, and are continuously waking up.

If you're thinking, "Well, I always sleep through the night, so that can't be why I'm so tired," you might want to pay closer attention. The amount of time that you're awake can be so small that you don't even realize or remember it the next morning — but it's preventing you from completing a full sleep cycle.

The study concluded that loneliness is a significant predictor of sleep fragmentation, and that "lonely individuals do not sleep as well as individuals who feel more connected to others."

You care a lot about material possessions.

Materialism and loneliness are also believed to be linked: One study of 2,500 people over six years found that loneliness causes people to frequently go out and buy material things (but also points out that it does not go the other way — materialism does not cause loneliness). 

So, if you suddenly find yourself fixating on material possessions and shopping more than normal (filling a void, if you will), you could be going through a rough patch. 

You find yourself taking really long and hot showers.

In a study published in the scientific journal "Emotion," researchers found a link between physical and social "warmth." Essentially, if a person feels socially cold (aka lonely), they're more likely to try to substitute emotional warmth with physical warmth by taking hot showers and baths.

You can't stop binge-watching shows.

A tendency to binge-watch can indicate a few things: loneliness, depression, and a lack of control. A study done at the University of Texas at Austin found that loneliness and binge-watching TV are linked in some way.

They found that "the more lonely and depressed the study participants were, the more likely they were to binge-watch TV, using this activity to move away from negative feelings." 

You are consistently making mountains out of molehills.

If you feel like you've been more stressed than normal recently, you could just be lonely. According to Psychology Today, "lonely individuals report higher levels of perceived stress even when exposed to the same stressors as non-lonely people, and even when they are relaxing."

So if your past couple of months haven't been inherently more stressful than normal, but you feel like you've been extra stressed about little things, it could be loneliness raising your levels of stress hormones and blood pressure.

You're spending a lot of time on social media.

A study found that heavy use of social media was associated with feelings of social isolation: those who spend more than two hours a day on social media were twice as likely to feel lonely than those who spent 30 minutes or less on social media platforms.

However, the causation is unclear: does loneliness cause an increase in social media use or does social media use increase feelings of loneliness? Either way, "What we know at this point is that we have evidence that replacing your real-world relationships with social media use is detrimental to your well-being," Holly Shakya, an assistant professor in the division of global public health at the University of California, San Diego, told NPR.

You hang out with other lonely people.

A 2010 study found that loneliness "spreads through a contagious process." So even if you yourself don't feel lonely, counter intuitively your social network could be changing that. In other words, if you have friends that feel lonely, you're more likely to experience feelings of loneliness too.

According to research published in the Journal of Personality and Social Psychology, you're 52% more likely to feel lonely if someone you're directly connected to is lonely.

You've gained weight.

Since weight gain is a common side effect of depression, it doesn't come as too much of a surprise that weight gain could also signify loneliness.

Mental health counselor Ashley Turner told the UnLonely Project that "loneliness is one of the biggest drives toward overeating. We naturally turn to food to nurture and nourish ourselves. It is the most obvious way to fill ourselves up. However, when we are lonely, what we are actually craving is a little personal interaction, intimacy, love or friendship, someone to share our lives with."

It feels like you constantly have a cold.

Loneliness can lead to a weakened immune system, leaving you susceptible to colds and other viruses. It can become a vicious cycle, as staying at home with a cold will isolate you from others, in turn increasing loneliness. 

A study from UCLA found that the immune system of lonely people focuses on bacteria rather than viruses, meaning that lonely people are more susceptible to viral infections.

Loneliness can also lead to an increased risk of heart disease, arthritis, Type 2 diabetes, dementia, high blood pressure, inflammation, and even issues with learning and memory, and is said to be a bigger health risk than obesity or smoking.

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