“We all live in a subjective reality.”

I heard the phrase dozens of times in college; but I didn’t get it. I pretended to follow the dorm room conversations, feigning real understanding to save face. Somewhere in my late 20s the phrase connected with some meaning: That an event can be interpreted as many different ways as their are people to witness it, and again by those that are told about it.

These interpretations are the product of whatever has happened in your life influencing your decisions. Every single thing you experience in your life is colored by what came before it – your individual subjective reality.

Two examples come to mind:

A good friend of mine lives in a world of violence. He carries a concealed weapon with him at all times, sleeping with a knife by his bed. He keeps his things close when he’s in public and watches others with the detailed glower of constant vigilance. The world around him is a threat.

Counter to that, my husband has never thrown a punch. He took karate for fun as a kid but has never struck someone in violence or anger. He still has the teddy bear his grandmother gave him when he was four and he’s never held a gun. His world is not threatening.

They live and work in the same city and run in similar circles, but interpret them differently. Seems simple. Sounds straight forward. Despite this understanding, I’ve struggled with how to apply it.

These realizations about the perception of stressors and interpretation has me observing not only my own mind for moments of reaction and chaos, but the outlooks of those around me. How obviously stressful does this person or that person make their world? And how does it color their interactions, body, and soul? How does being near them affect mine?

Having spent 6 years as a Lifestyle and Habit Change Coach and Personal Trainer in New York, I spend a lot of time with people who are struggling with their realities and sense of self. Learning how to control my interpretation of events and other’s effects on my reality isn’t just a mindfulness practice; it’s professional survival.

Hormonally, we all have two general states of being. Sympathetic, which you probably know as “fight or flight”, and parasympathetic, or “rest and digest”.

In a sympathetic state your body releases adrenaline, cortisol, and other hormones to allow for increased metabolism and response. Insulin is increased so plenty of blood sugar is accessible to your muscles, ready to run or fight or think. The few times in my life this has been obvious (car accidents, big games, attempted assaults) I can remember seeing more clearly. Time slows as your brain becomes hyper-aware. This is your body on stress.

Parasympathetic states are the opposite (think parachute = coming down). It’s relaxation. Your body releases feel-good hormones to tell your heart to slow, blood pressure to drop, and digestion to continue. This is when maintenance is done by your immune system as well.

In a dangerous world you live in a sympathetic state. You’re on high alert, meaning your heart rate and blood pressure are elevated, your insulin sensitivity (linked to diabetes) is out of whack, your digestion is slowed. You never get into maintenance mode. Eventually your immune system starts to struggle.

Living in a city like New York, I am surrounded by people who are drowning in their own stress. Under-slept, over caffeinated, poorly nourished – their world is filled with frustration and struggle. In our ancient past this struggle would’ve been to find food and keep safe; now it’s to “get ahead” or “keep ahead” or resolve whatever your daily personal anxiety trigger is.

We are the most advanced society in the history of humanity. We have low poverty, high employment, education, medicine. I’m not saying it’s perfect (it’s so definitely not) – but what’s the shape of the world we’re collectively creating? Our bright minds are running themselves into the ground, believing it’s “normal” because everyone they know is also doing it. These bright minds are not giving themselves the opportunity to realize: we’re doing it to ourselves.

I’ve been that person. I’ve ground myself into a fine paste, longing every day for bedtime just so I can relax, only to get there and not be able to sleep because I dread getting up in the morning. That’s not living. That’s projecting myself into an uncertain future. One that could be amazing if I had not decided beforehand that it isn’t.

Early in 2017 I took an epiphany filled vacation. Returning to New York I realized that time was so full of insight because I was living fully in the moment. I wasn’t worried about the next thing I had to do. I wasn’t projecting myself into a world that wasn’t there. I was acting and reacting.

Applying that lesson, I’ve realized the more I focus on doing what I’m doing in any given moment, the happier I am.

Part of shaping the world I’m in is being present in it. Is letting go of stress from things that have already happened, or of projecting to things I don’t have to work on yet.

None of this is new. None of it revolutionary. But hearing it, understanding it, and doing it are all very different things. Applying the lesson: when something violent enters my world, then my world is violent; otherwise, my world is at peace.

I understand the ideas more deeply. Now to discover living the difference.

Darlene McCullough is a Certified Personal Trainer, Nutrition & Habit Change Coach working in the West Village. You can enjoy watching her cats interrupt her yoga on Instagram @darlenemcc or find her dispensing science backed wellness information on YouTube.com/FeministFitness.