4 Surprising Ways Other People Affect Your Health

4 Surprising Ways Others Affect Your Health in lineJean-Paul Sartre in one of his famous plays said, “Hell is—other people.” I think most of us might sympathize with that claim depending on the day and the person we’re dealing with. On the flip side, people can be the source of our greatest joys. His sentiment, regardless, speaks to the strong impact others can have on us. Whether we like it or not, we all live (and need to live) in some relation to others. None of us exist in a vacuum, and research on extreme isolation suggests the real hell on earth might be exactly that. So make no mistake—how people make us feel is not just the stuff of poetry and philosophy. Other people can and do influence our immediate physiology as well as our ongoing health. What does this process look like though? How does it play out in our lives? Let’s examine a few examples.

Evolution shaped us to be intricately social creatures. From the time of infancy, we’re innately directed to be highly attuned to those around us—first to our mothers and/or primary caregivers and later to our peers and larger community. Complex neurological patterns guide our instinctual process of observation and emulation. Researchers have long studied “mirroring,” the subconscious mechanism that moves us to adopt the subtle behavioral signals of someone whom with we’re likely to establish rapport, trust and empathy—the cornerstones of human connection. Interdependence and the social tools to support it are written into our DNA.

But the effects go even deeper than observational behaviors.

Studies show that people’s brain waves begin to oscillate in the same rhythms during verbal exchanges they deem as positive. This goes for group settings and even with strangers.

Likewise, our heart rates synchronize with loved ones during personal exchanges or when we see them experiencing stress.

Communal rituals may hold the same sway. Participants in choir performance, for example, have been shown to synchronize heart variability.

So it shouldn’t surprise us to know that the company we keep has the power to influence our daily choices and, by extension, our overall well-being. This isn’t to let us off the hook. None of us is operating from a pure monkey see, monkey do mentality. But we can understand (and at times harness) the latent proclivity to go with the flow, whether its leading where we want to go or not.

Here are just a few ways the company we keep can affect our bodies and minds.

Weight/body composition

For better or worse, studies have shown that the kinds of folks you associate with can affect your waistline. A New England Journal of Medicine study found that having one friend who was obese raised the risk of obesity by 57% over the course of 30 years. Friends, the study showed, were more influential (even long-distance) than family members. This is enough to make anyone sit up and listen.

In fact, some research suggests that the social network model can be exploited to actually prevent or dial back the onset of obesity across groups. Offering weight management support for random members of a social cluster may have reverberating effects.

In other words, if one person (or several people) take charge of their body composition, the effects can effectively spread to other members of the social group.

Be the change, as they say, seems to apply here. Wearing a Grok shirt to family picnics or gifting a Primal book to your neighborhood’s Little Library may not hurt either. Share the message and connect with others who reflect the healthy “norm” you want to embody in your life. The effects can spread wider than you may know.

Mood disorders

Some years ago there were headlines claiming that depression was contagious. As most sensationalist headlines do, it got big attention at the time, but it only told part of the story. Indeed, some research does indicate a social clustering of depressive symptoms, particularly among women. Oddly, the study above found that the onset of depression in a spouse didn’t impose the same heightened risk of depression in his/her partner to the same degree as having a friend with depression did. This contradicts other research that revealed 40% of those living with a diagnosed depressed person met clinical criteria for depression as well.

Other findings, however, demonstrated the flip side of this phenomenon, showing the “spread” of happiness. The closer you live to, and the more you interact with, happy people, the findings suggest, the more potent the effect. Having a sibling or friend who experienced happiness and lived within one mile raised the probability of being happy by 25%. Living with a spouse who was happy showed a similar effect. Other research on adolescents also affirmed the spread of happiness, showing that having happy friends raised the probability of recovery from depression.

What we can take from this? Above all, we can understand the need to actively and selectively attach and detach from others’ feelings. When the mood is high, and people around us are happy, we can let ourselves soak it in. When it’s low, offer empathy and support, but stay vigilant to maintain your own emotional independence.

When it comes to depression, given our human propensity to be influenced by others’ behaviors, we must take charge of our own feelings. Meditation techniques around detachment can help fortify our own emotional boundaries. Likewise, taking responsibility for our lives (being selfish) means ensuring we don’t become fixated on another’s situation. The more problems there are around us long-term, the bigger life we need to live.


One study of 3000 students from the U.S. Air Force Academy showed that a student was three times more likely to fail basic fitness requirements if more than half of his/her friends fell out of shape. (PDF)

On the other side of the coin, direct support from others can spur us to exercise more consistently and to make more of our workouts. A study of 1000 women commissioned by Virgin Active found that over 30% of respondents called their friends their “main motivation” for staying fit. Sixty-four percent of participants said they train harder with others than if they go it alone. The study found subjects worked out longer and went to the gym more often if they went with a friend. Other research found that people benefit from others’ fitness only when they perceive support for their own exercise efforts as well.

Here’s where community might just be essential. Even if you’re an introverted exerciser who’d rather hit the gym or the trail alone, you’ll benefit from a supportive set of friends. Accountability and encouragement might come over social media for some of us as well as it does in paired workouts for others. Choose the support you want for your fitness, and go get it.

Immunity and heart health

Have you been seeing red lately? Maybe it’s the times, but this one’s been on my mind lately. Anger, as anyone can imagine, doesn’t do our health any favors, and research confirms that assumption. Just recalling an angering experience suppresses immunity for six hours.

Not surprisingly, the effects can be much more deleterious. Angry outbursts can triple your risk for stroke within the next two hours. And if anger is a chronic problem for you, research suggests you’ll earn yourself double the risk for cardiovascular disease.

What does anger have to do with other people? (I can hear the snickers through the screen.) There’s a post unto itself, but let me just highlight the impact of anger on social media. A team from Cornell University cycled through 70 million tweets, observing user interaction and assigning each tweet one of four emotional labels (sadness, joy, disgust and anger). Of all the emotions, anger, they found, was more contagious than any other response. Anger had the widest span as well, lasting through three degrees of separation.

What’s the take-home here? It may not be a bad season to cull your social media feeds or take an outright break if you find the collective fury is disturbing your peace. Keeping yourself on an even keel isn’t selfish. It constitutes good self-care—and just may be a wise act of public service that keeps immune systems and tickers strong.

Thanks for reading, everyone. I’d love to hear your thoughts on the influence of others on your daily health, well-being and peace of mind. Have a great end to the week.

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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23 thoughts on “4 Surprising Ways Other People Affect Your Health”

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  1. Considering we are such social beings, this doesn’t surprise me one bit! It is fascinating to see, though, the extent to which other’s moods and physical health can affect us, even those who aren’t close friends, but those who live in our radius.

    1. Sometimes hell really is other people. Anyone who has ever had to deal with a difficult boss or spouse, or a friend or family member with a personality disorder knows how difficult it is to remain upbeat in such cases and not get sucked into a “black hole” of depression and negativity.

      1. Totally true, Shary! I have had times where I feel like I physically have to remove myself from a situation because another person is totally dragging me into the ground.

        1. I’m in there with you Emily and Shary. I took a break from Twitter over the summer because I saw so much professional nastiness. This troubled and angered me. I’m back on, now, but I stick to my list. Professionally, I learn too much form other people to justify completely not being on Twitter. If anyone gets snarky, though, boom! I remove them.

          But living with depressed or angry people isn’t as simple, The long term emotional cost can’t be underestimated. I think it’s important to remember the power of spoken words – for better or worse. We live up to, or stoop to the meaning behind our words. When angry or depressed people have outbursts, their effect on others and themselves feels even more potent. Physically removing yourself becomes necessary for the survival of your own mental health.

          1. I think that recognition of the potential changes a person might have on you can stop them from occurring. This way at least, fat people aren’t isolated due to others fearing the changes they’d have on their habits.

  2. “research on extreme isolation suggests the real hell on earth might be exactly that”


  3. This reminds me of a saying my mom always said when I was a kid. “You are only as good as the company you keep.” Mom knows best!!

  4. A really great post. My hurdle is fitness. I need a Primal friend or two to do workouts/play/adventures with.

  5. Totally agree with this! Especially the happiness thing. Positive energy is contagious. And staying fit and healthy is easier when you have friends and family members who are doing the same thing. I’ve heard that you become the average of the five people you spend the most time with. And for those people whose friends and families are not on board with healthy living, forums like this can be really helpful.

  6. Even though I’m a pretty happy person who rarely lets my own woes get me down, I increasingly find people, even friends wear me down with their problems, so much so it feels like those problems become my own. Although I want to be there for friends in times of need, I end up feeling like a permanent crutch and have to take the selfish stance and distance myself from them.

  7. This is so true! I always think about the saying that you’re a compilation of the 10 people you spend the most time with. Especially since health and fitness routines can become so habitual, it makes sense that others impact our abilities to follow through, maintain a schedule, and be aware of health.

    1. Hi Diana. I appreciate your perspective, and here’s a different one. If everyone chooses to spend time with only happy, positive, fit, thin people who do meaningful work or make great money, then who is going to help those who are not there yet, but want to be? Just wondering if this personal development maxim is more myth than fact.
      I think compassion asks us to “be the change” in the company of both those of like mind and those who are very different. If happiness is contagious, then the fastest path to a world that works for everyone is to share our happiness by being present with those who don’t yet experience it very much.
      This is not any kind of judgment, and this practice is best left as a possible choice for anyone who feels inspired in this way. Just wanted to highlight another way of looking at it. Thanks again for your thoughtful contirbutions here.

  8. I’ve always hated gyms. I find it completely demotivating to work out in front of other people. That’s why I’m giving You Are Your Own Gym a try, all in the comfort of my own living room. That said, I can totally see how the lifestyle of those closest to you can affect your own level of fitness. Heck, even in terms of diet…. Avoiding grains was incredibly easy when I was a single man. Now that I’m in a relationship with a woman who does not see eye to eye with my dietary choices (she stilll believes the fat=bad, grains=good mantra, and thus is convinced I’m going to die of a heart attack at 40), it’s incredibly difficult not to dig in when she’s making a nice plate of Mac & Cheese!

  9. I enjoyed this topic, and it makes me want to spread happiness and influence others to make healthier choices. This was a good pick me up after watching depressing documentaries about sugar and childhood obesity. Would love to have a Grok shirt (in green)!

    1. Also the information about anger and immunity was a shock to me. I’m far less angry than I used to be ever since caring for my own baby, but I’m having more trouble lately having to care for a toddler while being 8 months pregnant. I wonder if frustration is the same here with the effect on immunity, I still don’t get angry (how could I get angry at such a beautiful little lifeform), but I do get frustrated a lot.

  10. I think sometimes it’s ok to “catch” other people’s anger. It took me a long time to realize that the epidemic of police violence against black people was real. Now I know, and I am outraged. This is not wrong. There’s probably an evolutionary reason for contagious emotions like anger: we need to know when there’s a threat. This is a real threat. Unfortunately it has become a divisive rather than unifying issue.

  11. I can definitely attest to this; my parents are visiting right now, and they’re taking me out to eat EVERY NIGHT. 9I forgot how much I loathe eating out often), but it’s a social thing with them, so of course I’m going to go and spend time with them.

    That said, my mom is a nurse who follows the CW kind of dieting, and every time I choose something heavy in meat and low in carbs, she reminds me that “your body needs carbs to function.” …and then I find myself eating things that make me feel crappy, because I know it will make her happy…


  12. It’s amazing how others influence us to eat unhealthily, refrain from doing exercise, and take breaks from doing the things we usually do to keep ourselves fit. Social media definitely has a role in this, because once you see photos of pizza or a trip in Europe, your salad suddenly doesn’t look as appealing as it did before!