I’m blessed to live in a safe, walkable town with plenty of trees, good sidewalks, a pretty downtown, and several lovely parks.

I used to jog frequently and play squash, but I’ve grown lazier. I now enjoy long walks. On days I’m too busy working, I’ll often walk late at night around our local middle school because it’s nearby and has good lighting. (I occasionally see deer, foxes, and bunnies!)

But nothing compares with the magic of walking on a January 13th that feels like April 1st. Walking in the dark is okay, but nature walks are magical:

Nature as medicine is a cliché with a robust pedigree that you can trace back to our sun-worshipping, tree-venerating proto-ancestors millennia ago. The idea started going scientific in the early 1980s: that’s when Harvard entomologist E.O. Wilson published his book Biophilia, on humanity’s innate affinity for nature; when the Japanese Ministry of Agriculture, Forestry, and Fisheries coined the term shinrin-yoku, or forest bathing; and when a researcher named Roger Ulrich noticed that patients recovering from gallbladder surgery at a Pennsylvania hospital were discharged nearly a day earlier, on average, if they had a view of trees outside their window.

These days, the link between cumulative time spent in natural settings and health outcomes—including the big one, longevity—is solid. There’s data on cancer and heart disease, anxiety and depression, immune function and stress hormones, and more. “It’s not just one study,” points out Harvard epidemiologist Peter James, whose 2016 analysis of the 108,000-person Nurses’ Health Study found a 12 percent lower rate of nonaccidental mortality among those with the most greenery in a 250-meter radius around their home address. “It’s 500 studies.”

…A 2019 study from Britain’s University of Exeter offered a handy benchmark: 120 minutes of nature per week, it found, was enough to measurably boost health and well-being.” – https://www.outsideonline.com/health/wellness/naturequant-app-outdoor-data/

The temperature here in Connecticut today – January 13th – hit 57 degrees.

Our recent winters have been mild, with little snow, which is probably why a tick found my wife on December 29th. (My wife’s fine. The tick fared less well.) Insects are now surviving winter, forshadowing an extra-buggy spring.

Even so, 57 degrees in mid-January is still special. I was thrilled and eagerly went for a long walk because getting out and moving is so good for us in so many ways.

I took the photo above on my walk. There has been a crazy amount of rain recently, so our local river was flowing high and fast. I stopped and stared. A sense of wonder is health-enhancing:

Awe is the emotional state that arises “when people feel that they are in the presence of something grand that transcends their current frame of reference.”

Increasingly, robust research supports the value of awe and wonder; be it stargazing, experiencing vast landscapes, or witnessing humans at their best. Such experiences buffer stress as they bolster our well-being and renew our energy.

– David Fessell, M.D., “New Insights From the Science of Awe,” Psychology Today, https://www.psychologytoday.com/us/blog/unlocking-your-potential/202112/new-insights-the-science-awe

I really enjoyed today’s walk, for numerous reasons:

“Antifragile” systems, like our bodies, grow stronger in response to moderate, intermittent stressors. Conversely, extreme and chronic stressors are destructive because evolution hasn’t equipped us to handle extreme or endless stressors. We become healthier every day we exercise an hour because our body’s tissues rebuild better over the subsequent 23 hours, but running marathons and ultramarathons can damage us by inducing more damage than our bodies can easily recover from.

At the opposite extreme, sitting on our butts all day also damages us by never triggering our bodies to grow back stronger. When antifragile systems are starved of normal, expected stressors, they fail to develop properly. This is the principle behind “the hygiene hypothesis” that allergy, asthma, and autoimmune disease are much less prevalent among children raised on farms, for example, because those exposed to animals and plants receive a healthy exposure to microorganisms and pollen, allowing their immune systems to calibrate properly, whereas immune systems of those growing up in sterile environments are prone to overreact to innocuous stressors because they haven’t learned that not every microorganism or pollen requires a body-wide Defcon 1 response ():

[T]he hygiene hypothesis was corroborated by various findings on allergies in relation to infections with parasites, viruses, and bacteria, for example, helminths, hepatitis A, measles infection and vaccination, Helicobacter pylori, or tuberculosis…

A variant of the hygiene hypothesis suggests that our immune system was originally well adapted to ubiquitous microorganisms (‘old friends’), and loss of these exposures due to enhanced hygiene resulted in an imbalanced immunoregulation and consequently in immune disorders such as asthma, allergies, and other inflammatory diseases, for example, multiple sclerosis, type 1 diabetes, and inflammatory bowel disease.

– Markus Ege, Susanne Rompa, “The Hygiene Hypothesis of Allergy and Asthma,” Encyclopedia of Immunobiology, 2016, https://www.sciencedirect.com/science/article/abs/pii/B9780123742797160047

Your body could not function without bacteria. We think of our self as being one thing, but it’s really more like we’re a union of roughly 30 trillion little human cells plus another 38 trillion bacteria, which generally work together to keep us alive. Of course, sometimes human cells go rogue and try to kill us (cancer) and some bacteria rage out of control, making us ill. But a healthy “human body” works in harmony with bacteria living inside and on us since each of us is, numerically, more bacteria than human:

[T]he number of bacteria in the body is actually of the same order as the number of human cells, and their total mass is about 0.2 kg.

Thoroughly revised estimates show that the typical adult human body consists of about 30 trillion human cells and about 38 trillion bacteria.

– Ron Sender, Shai Fuchs, and Ron Milo, “Revised Estimates for the Number of Human and Bacteria Cells in the Body,” PLOS Biology, 2016

(If you’re interested in better understanding the human immune system, Immune: a Journey into the Mysterious System that Keeps You Alive by the founder and head writer of the fabulous science video cartoon series Kurzgesagt is wonderful.)

For nine months of the year, I enjoy taking many long walks, ideally in daylight but sometimes just walking around our well-lit middle school late at night.

I enjoy walking with my wife or friends or with my headphones and my embarrassingly large collections of audiobooks and podcasts. A good conversation/audiobook/podcast enhances my walks, and walking enhances learning. I discovered this back in grad school. After meeting my wife, I started learning Chinese. I created stacks of flashcards and discovered I learned Chinese characters and words more efficiently while jogging or walking. I was better able to focus, presumably because my brain was more alert and attentive while exercising.

Many creatives discovered the power of exercise to enhance learning and creativity long before I did, and many scientists have now proven this:

  • “A person’s creative output increased by an average of 60 percent when walking.” – Stanford study finds walking improves creativity

  • “a Swedish study that looked at 1.2 million boys, who were evaluated at 15 for fitness and IQ, and then tested again when they began compulsory military service at 18 [found that] if they got fitter, they also got smarter. That was even true of identical twins. If one exercised but the other didn’t, the one that moved showed a cognitive benefit that the one who sat around didn’t. This was clearly down to the exercise and not anything inborn.” – How Exercise Makes You Smarter, Happier, and Less Stressed

  • “Gros discusses the centrality of walking in the lives of Nietzsche, Rimbaud, Kant, Rousseau, and Thoreau. Likewise, Rebecca Solnit has profiled the essential walks of literary figures such as William Wordsworth, Jane Austen, and Gary Snyder in her book Wanderlust, which argues for the necessity of walking in our own age, when doing so is almost entirely unnecessary most of the time. As great walkers of the past and present have made abundantly clear—anecdotally at least—we see a significant link between walking and creative thinking.” – How Walking Fosters Creativity: Stanford Researchers Confirm What Philosophers and Writers Have Always Known

Here are a few videos from experts on how exercise supercharges our brains:

Though I love walking and know how great it is for me, once winter hits and it gets dark crazy early and cold, I struggle to get out the door for walks.

Today, I needed only a short-sleeved shirt, all the better to catch some rare winter vitamin D.

I felt very fortunate to enjoy a wonderful mid-January day, and stopping to consciously appreciate our good fortune is also health-enhancing. A sense of gratitude and appreciation is healthy, according to Harvard Medical School, The Mayo Clinic, The Cleveland Clinic, and The American Heart Association. I also appreciate how fortunate I am to live in a community that’s green, safe, and pretty walkable.

American life has been designed around our automobiles:

Parking is the dominant physical feature of the postwar American city.

Not homes. Not strip malls. Not streets, highways, or stroads. Parking. We have a lot of the stuff. A few superlatives can express the sheer amount:

  • There are somewhere between 800 million and 2 billion parking stalls in the United States.

  • There are between 3 and 8 stalls for every registered vehicle.

  • Surface parking lots alone cover more than 5% of all urban land in the United States.

  • That represents an area greater than the states of Rhode Island and Delaware combined.

  • In Los Angeles, parking occupies more land than housing.

Daniel Herriges, Strong Towns, https://www.strongtowns.org/journal/2019/11/27/parking-dominates-our-cities-but-do-we-really-see-it

SimCity is a video game that simulates a city, but game designers decided real-world parking would have destroyed their game’s aesthetic!

Geoff Manaugh: While you were making those measurements of different real-world cities, did you discover any surprising patterns or spatial relationships?

Librande: Yes, definitely. I think the biggest one was the parking lots. When I started measuring out our local grocery store, which I don’t think of as being that big, I was blown away by how much more space was parking lot rather than actual store. That was kind of a problem, because we were originally just going to model real cities, but we quickly realized there were way too many parking lots in the real world and that our game was going to be really boring if it was proportional in terms of parking lots.

Manaugh: You would be making SimParkingLot, rather than SimCity.

– Geoff Manaugh, “Sim City: An Interview with Stone Librande,” BldgBlog, https://www.bldgblog.com/2013/05/sim-city-an-interview-with-stone-librande/

American cities and towns are engineered around our cars to such an extent that many Americans lack green spaces, clean air, and places to walk. These have become luxuries only the rich can afford:

Leading real estate platform Redfin, which owns Walk Score, says that walkability can increase the average home price sale by 23%, or a whopping $78,000. One study also found that each additional Walk Score point [on its 100-point scale] increased a home’s value by between $500 and $3,000.

…more than 140 U.S. cities have an average walkability score of just 48 out of 100.

– https://www.thecooldown.com/green-home/walk-score-walkability-rankings-home-value-price/

When we spend our lives indoors or in cars, we miss out on sunlight. Vitamin D is essential for our bodies:

Vitamin D is both a nutrient we eat and a hormone our bodies make. It is a fat-soluble vitamin that has long been known to help the body absorb and retain calcium and phosphorus; both are critical for building bone. Also, laboratory studies show that vitamin D can reduce cancer cell growth, help control infections and reduce inflammation. Many of the body’s organs and tissues have receptors for vitamin D, which suggest important roles beyond bone health, and scientists are actively investigating other possible functions. – “Vitamin D,” Harvard School of Public Health, https://www.hsph.harvard.edu/nutritionsource/vitamin-d/

Sadly, few of us get enough, especially in winter:

“Vitamin D is well known to support bone health, but it also plays a role in the health of your heart as well as your GI tract. It is tougher to get it because a lot of the absorption and how the vitamin gets transformed to a usable substance in our bodies is from the sun,” said Dr. Mike Ren, assistant professor in the Department of Family and Community Medicine at Baylor. “You need the sun high in the sky, not when it’s rising or about to set, for your body to effectively absorb sunlight to absorb the vitamin D.”

While some fatty fishes and seafood naturally contain some vitamin D, it is not commonly found in other foods, so people typically do not get enough vitamin D from their diet. Sun exposure helps, but in the fall and winter months when there might be less sunlight, people tend to be more deficient. The typical adult needs 800 international units of vitamin D per day, which roughly translates to 15 to 30 minutes of good, direct sunlight.

– Homa Warren, “Getting adequate vitamin D in the fall and winter,” Baylor College of Medicine, https://www.bcm.edu/news/getting-adequate-vitamin-d-in-the-fall-and-winter

Insufficient sunlight in childhood is also the leading cause of nearsightedness:

“Data suggest that a child who is genetically predisposed to myopia are three times less likely to need glasses if they spend more than 14 hours a week outdoors,” says optometrist Donald Mutti, OD, PhD, of The Ohio State University College of Optometry. – “Scientists study effects of sunlight to reduce number of nearsighted kids”

Ophthalmologists now urge their young patients to go outside in the sun:

Every patient who comes to pediatric ophthalmologist Noha Ekdawi, MD, gets the same prescription: Spend more time outdoors. Sunlight is the best way to prevent myopia, or nearsightedness, in children.

…Nearsightedness in children has increased at an alarming rate over the past 30 years. It is estimated that about 40% of children ages 6 to 19 years are nearsighted; in Asia, the rate is nearly double.

…[H]aving severe myopia puts children at risk of potentially blinding eye problems down the road, including retinal detachment, glaucoma, early cataracts and myopic maculopathy, a leading cause of blindness worldwide.

– “Prescription for Keeping Children Out of Glasses: Sunshine,” American Academy of Ophthalmology

(I wish I had known this when I was a child. I was an inveterate indoor reader and developed bad myopia. In my late forties, I suffered a detached retina, a story for a future blog post.)

I try hard in the winter to sit outside for twenty minutes around lunchtime whenever I notice it’s sunny (and not unbearably cold/windy).

Seeing grass, trees, and lakes/rivers soothes us, with measurably positive effects on our mental health and learning:

Green environments, such as open spaces with big trees, are related to reduced symptoms of ADD and ADHD (Faber Taylor & Kuo, 2009; Faber Taylor, Kuo, & Sullivan, 2001).

Tree cover is strongly linked to student academic performance (Kuo, Browning, Sachdeva, et al., 2018; Kweon, Ellis, Lee, & Jacobs, 2017; Matsuoka, 2010). In one study, views of trees and shrubs at schools, as opposed to grass, were strongly related to future education plans and graduation rates (Matsuoka, 2010). Li and Sullivan (2016) found that students who had views of trees and green environment from their classrooms, as compared to being in a room without windows or a room with a view of a brick wall, scored substantially higher on tests measuring attention, and they had a faster recovery from a stressful event. Students who learn in the presence of trees and nature have improved classroom engagement (Kuo, Browning, & Penner, 2018).

– Jessica B. Turner-Skoff and Nicole Cavender, “The benefits of trees for livable and sustainable communities,” 8 July 2019, https://nph.onlinelibrary.wiley.com/doi/full/10.1002/ppp3.39

Similarly:

“A growing body of research shows that regularly spending time around trees provides a wide range of human health benefits, from lowering stress to improving cognition to boosting longevity, according to experts.

In a September 8, 2021, interview on WBUR’s Radio Boston, Peter James, assistant professor in Harvard T.H. Chan School of Public Health’s Department of Environmental Health, said that trees’ effects on us “translate into long-term changes in the incidence of depression, anxiety, cognitive decline, and chronic diseases including cardiovascular disease and cancer.””

– “The Health Benefit of Trees,” Harvard School of Public Health, https://www.hsph.harvard.edu/news/hsph-in-the-news/the-health-benefits-of-trees/

If you’ve read this far, hopefully you’re inspired to go outside and walk/jog more often. Exercise is better than any statin or diabetes drug for your health. If you make a habit of moving around outdoors (with an audiobook/podcast or a friend) and/or sitting in the sunshine with a good book, your body and mind will thank you!