For 99.99% of humanity, we never worried about getting this crucial vitamin because we were bathing in it [1]. But over the past couple hundred years, we’ve mostly escaped it except for weekend adventures. And if you think I’m referring to the Vitamin D provided by sunlight, you’re close! But I’m talking about Vitamin N… Nature! What benefits does exposure to nature have on stress levels, immune health, and our cognitive state? If the benefits are really derived from the environment, what mechanisms are involved? What’s the optimal dosage or time in nature needed to reap these benefits and will I show you my secret source for this elixir of life? Well, if I did, I wouldn’t want tens of my followers all flocking there at once, it getting overcrowded, the town having to close it down, and me never being able to hike there again. So maybe I won’t. Or maybe I will, we’ll see. Let’s get into it!

Benefits of Exposure to Nature

When scavenging through the research, it’s clear that there’s a strong association between experiences in nature and increased psychological well-being. This includes everything from an increase in mood, happiness, and stress all the way to improved cognitive function regarding memory, decision making, and creativity. It’s also clear that there’s a strong association between experiences in nature and a reduction of risk factors or burden of mental illness. This includes improved sleep and decreased stress which can reduce your risk for depression, anxiety, and ADHD. But nearly all of these benefits from nature are from studies showing an association [2]. And association does not mean causation. It could just mean that healthy people tend to seek out nature rather than nature making people healthier. It’s like how tutored students receive lower grades on average than non-tutored students. It’s not that tutoring brings down students’ grades, it’s that students’ who use tutoring are usually starting out with much lower grades to begin with. So, just because there’s an association with nature and these benefits doesn’t mean that nature’s causing it. It’s why we need to tease out the mechanisms and perform interventional trials to understand how nature is affecting us.

In one interventional trial, they tested participants cortisol levels which can be a gauge for stress. They used this measure as a control for the participants. They then asked the participants to walk in a park forest for two hours in the morning and afternoon, respectively. Afterwards they tested the participants cortisol levels again the next day and saw a significant drop compared to their control levels. And this drop in cortisol lasted about 7 days after their exposure to nature indicating a lowering of stress levels. They also measured and showed an increase natural killer cell activity [3]. Natural killer cells are white blood cells that can kill tumor cells or cells infected with a virus [4]. Therefore, indicating a positive immune response from nature exposure too. But interventional studies can be expensive and difficult to perform especially when testing lifestyle factors.

That’s where observational studies can be useful as you’re not asking groups of patients to perform different interventions. You’re letting them go about their normal activities and observing their actions and results. In one observational study, they looked at patients who were recovering from surgery. Some patients were in a hospital room whose window looked out at a brick wall. Other patients were in a hospital room whose window looked out at nature. And what they found was that the postoperative stays of the patients looking out the window of nature were shorter, used less painkillers, and received fewer negative notes from their nurses [5]. What this indicates is that the mere visual presence of nature can have positive effects on one’s health and recovery. I mean not only can a window overlooking nature be helpful, but studies have shown positive effects with simulated green settings on mood, self-esteem, and stress too [6]. Look, here’s a picture from my hike. I just improved your mood and self-esteem. You’re welcome!

Mechanisms Involved

But what are the mechanisms involved here? How is experiencing nature, seeing nature, or even viewing artificial nature helping improve our health? I mean with the interventional trial regarding experiences in nature lowering stress levels and increasing natural killer cell activity, it was theorized that phytoncides released from trees decreased stress hormone levels which may partially contribute to the increased natural killer cell activity [3]. In other studies, it may have been that more greenspace leads to less polluted environments. Or it may be that more greenspace leads to more physical activity, such as walking and cycling [7]. Or it could be the complexity in patterns of the natural environments or fractals [5]. I mean look at the pictures of the floor, wall, and ceiling of my apartment. And compare that to those same views in the natural environment. There’s just so much more complexity in the textures, patterns, and shapes of the natural world compared to our built environment.

Either way, it can be difficult to assess which exact mechanisms are contributing to each positive health effect because multiple mechanisms are usually experienced at once. This can make it difficult to narrow down the effect and results can easily be misestimated. But no matter the mechanism, there’s sufficient evidence to encourage nature exposure to promote overall health [2].

Optimal Dosage of Nature Exposure

But how much nature exposure should you get? Again, this is a tricky question to answer. For 99.99% of our human history, all we did was live in nature, and you could easily assume the more the better. In a multi-study analysis, dose responses showed large benefits from short engagements in green exercise and then diminishing but still positive returns [8]. From this we could say that the largest benefits come from the first few hours you’re in nature each week. And the more time you spend in nature, the more benefits you get, but just to a lesser degree.

For me, my goal is always a 1-hour hike in nature each weekend. I like to roam through Corbett’s Glenn to check out the wildlife, walk the stream, and pose oddly in front of its teepee. I had a couple walk by as I was taking this teepee picture and let’s just say… it was awkward haha. Life of a solo creator.

Final Thoughts

It’s hard to tease out the exact mechanisms for why nature has health benefits for us. It could be the aroma, visual complexity, intricate sounds, or the less polluted air. Or it could simply be that nature encourages healthy behaviors like hiking and cycling. But more likely than not, it’s a combination of all these factors that make nature, or Vitamin N, an elixir of life. A vitamin than improves our cognitive function, decreases stress, and improves our mental state. And the more you submerse yourself in it, the more benefits you get. But even if you don’t have days or weeks to spend in wildlife, just an hour a week can have spectacular effects. Just don’t spend it at Corbett’s Glenn because I have dibs on that teepee.

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Hey, I am Brandon Zerbe

Welcome to myHealthSciences! My goal has always been to increase quality-of-life with healthy habits that are sustainable, efficient, and effective. I do this by covering topics like Fitness, Nutrition, Sleep, Cognition, Finance and Minimalism. You can read more about me here.