Here’s the truth about human health – nothing will kill you faster than loneliness.

We know all of this because scientists have studied social cohesion from a variety of angles and proven that disconnection is dangerous! We’ve studied partner relationships, friendships, civic involvement – it is all important and comprises our social health.

In one study, medical students without many friends had depressed immune systems. A 30 year study out of Roseto, PA found that support protected against heart disease even when diet wasn’t ideal. My own research has demonstrated convincingly that people without partnerships are at greater risk for depression.

We talk in public health about behaviors that offer something called protective effect and upping your social support has more protective effect than quitting smoking. Don’t hear me wrong – smoking is still bad!

The reason for that can be found in our physiology. Stress hormones surge when you’re feeling lonely or rejected, and if this happens too often or for too long, you start seeing problems.

Cortisol and adrenaline are useful when facing a real threat – they fire us up to respond, but they also shut down everything non-essential. Our heart rate and our breathing rate jump up and blood flows to our biggest muscles. Energy to the logical brain, digestive system, even blood flow to our extremities is diverted.

If hormone levels stay up, you can imagine the problems your body starts to face. At first, diminished blood flow to the extremities is just cold fingers and toes. Over time it might become neuropathy. Then, you stop feeling and have trouble picking things up or even balancing – in this way our body is trying to signal us – loudly, in the only way that it can – social numbing becomes physical numbing.

Our brain activity being interrupted may mean initially only that it becomes tough to find our car keys. Soon enough, we begin to have difficulty communicating, displaying empathy, or engaging in high-level thinking. This makes connecting with others even more challenging, and our isolation can easily become self-perpetuating. I work in military health today, but the social health issues I’m talking about aren’t strictly veteran problems. The angry veteran, the elderly shut-in, the person in an emotionally abusive relationship all deal with the same physical effects.

All of us have to prioritize it.

We all need the strength that an uplifting group of different – and thus complementary – personalities bring us. So I had to ask myself, as I encourage you to ask yourself – how are my people?

Do they support you? We need affirming, yes.

Do they challenge you? We also need different.

Connect. Be willing to get a little uncomfortable – It can completely change your health.