The Science of Setting Up a Healthier Home

A few tweaks to our homebound lifestyle can help us optimize our health

Photo: Blair_witch/Getty Images

Over the last few months, I’ve developed a new morning routine. After I brush my teeth but before I don my dog-walking shoes, I wander over to the windowsill to check on my microgreens. In the early days of the pandemic, I’d scoffed at the idea of quarantine hobbies, mostly because I didn’t have any. And then I stumbled upon an online seed catalog and began imagining a never-ending bounty of beet greens and lemon basil and ruby red chard.

Quick to germinate and easy to grow, microgreens are the perfect project for an inexperienced gardener confined to a one-bedroom Brooklyn apartment (that is: me). And I’ve been enjoying dining on my tiny harvests of peppery arugula and sweet pea shoots. But the biggest benefits, it turns out, have been less gustatory than psychological — there’s been something profoundly soothing, even hopeful, about beginning each day by tracking the growth of these small green shoots.

Over the last five years, I have spent countless hours poring over scientific literature, looking for clues about how we can create healthy indoor spaces. That research, which culminated in my book The Great Indoors, was sparked by the fact that I am decidedly indoorsy. So I was somewhat chagrined to learn that one of the best ways to foster a restorative indoor environment is to bring in elements of the outdoor one. And in an era of stay-at-home orders and 14-day quarantines, staying healthy and happy may require us to invite more nature, daylight, and fresh air into our homes.

It’s not a novel idea. In the mid-19th century, for instance, renowned nurse Florence Nightingale called for a major overhaul of hospitals, many of which were filthy, fetid death traps. Nightingale began campaigning for a new kind of hospital, one in which patients had ample access to sunlight, nature, and — especially — fresh air. “Natural ventilation, or that by open windows and open fire-places, is the only efficient means for procuring the lifespring of the sick — fresh air,” she wrote.

Nightingale became an advocate for a concept known as the pavilion hospital. The model, which became increasingly popular in the latter half of the 19th century, housed patients in long, skinny wards, with large windows arrayed along each wall and open lawns positioned between each ward. Designers of sanitoria, long-term treatment centers for patients with tuberculosis, also embraced the curative properties of nature, light, and air, creating facilities with gardens, balconies, and sunrooms.

These design ideas weren’t limited to hospitals. Around the same time, a series of housing reforms — including laws that expanded the yards and courtyards of overcrowded tenement buildings and required every room to have a window to the outdoors — helped slow the spread of infectious disease in New York and other cities. And modernist architects took inspiration from sanitoria to create open, airy, light-drenched homes. In 1926, architect Rudolph Schindler even went so far as to predict, “The distinction between the indoors and the out-of-doors will disappear.”

That did not come to pass. Over the course of the 20th century, a variety of scientific and technological advances, from the development of antibiotics to the advent of air conditioning, spurred major changes in building design. We began to close our buildings to the outside world, creating hermetically sealed, mechanically ventilated structures. Daylight, nature, and fresh air were out; sterility, technology, and efficiency were in. The energy crisis of the 1970s and a subsequent focus on sustainability spurred us to seal up our buildings even more tightly in an effort to make them more energy-efficient. Indoor ventilation rates plummeted, and we all but walled ourselves off from the natural world.

Science now makes clear that this was the wrong instinct. Fresh air, for instance, has serious health benefits, particularly during a respiratory pandemic. Covid-19 is primarily a disease of the indoors; the tiny, respiratory droplets that contain the virus tend to linger longer in closed, indoor spaces, especially poorly ventilated ones. Opening a window, or boosting the amount of outdoor air that’s coming in through an HVAC system, “is a great strategy to dilute the viral matter in the air and ward off outbreaks,” says Kevin Van Den Wymelenberg, who directs the Institute for Health in the Built Environment at the University of Oregon.

Bringing in more outdoor air can also reduce our exposure to any pollutants that happen to be hanging around indoors (and indeed, research suggests that indoor air can contain more pollutants than outdoor air). Indoor air pollutants, which range from the fine particulate matter we produce when we cook to the carbon dioxide we spew when we exhale, can irritate our lungs and impair our thinking; in one 2016 study, researchers found that increasing the supply of outdoor air boosted volunteers’ performance on cognitive tests.

And while we’re talking windows, we should make sure to keep our shades and blinds open. The ultraviolet rays in sunlight can inactivate a variety of microbes, including the coronavirus — although it does take some time — and daylight can be therapeutic. People who live in homes with more access to natural light report better psychological well-being while patients in sunny hospital rooms take less pain medication, recover faster, and even have lower mortality rates than those relegated to darker rooms. Daylight can boost mood, enhance learning, and reduce blood pressure. It also keeps our circadian rhythms in sync; blue-enriched morning light helps us remain alert during the day and improves our sleep at night.

There are ways to maximize the benefits of daylight without embarking on a major renovation, Van Den Wymelenberg says. To start, he suggests that we make sure to spend time in well-lit rooms in the morning. “Exposure to daylight in the morning is the most important in terms of keeping that sleep-wake cycle healthy,” he notes. Adding skylights or solar tubes; using light-colored, reflective paints and finishes; and moving desks and workspaces closer to windows could also pay dividends, he suggests.

Then, of course, there’s nature. We have an innate affinity for and attraction to nature, which can serve as a positive distraction, alleviating our stress and allowing our minds to rest. In a classic 1984 study, Roger Ulrich, a pioneer in the field of evidence-based design, discovered that surgical patients whose hospital rooms looked out onto a group of trees used fewer doses of strong painkillers — and were discharged sooner — than patients who had views of a brick wall.

Numerous studies now show that exposure to nature can reduce stress, anxiety, and pain; improve our attention and focus; and even boost our immune systems. “When the body feels truly safe and relaxed, that’s when we put our resources into things like building the immune system,” says Ming Kuo, who founded and directs the Landscape and Human Health Lab at the University of Illinois at Urbana-Champaign. “And nature seems to help. Nature is one of the settings in which people truly relax.” Window views of nature, photos of natural landscapes, indoor plants, and even nature sounds all seem to provide some benefits.

Plants can be a particular balm during times of extreme stress and confinement — crews working in space or in Antarctica, for instance, have reported taking great comfort in greenhouses and gardening. When every day feels the same, nature can serve as a visible reminder that time continues to march steadily on. I might be stuck in my apartment for the indefinite future, but I can still take solace in a few trays of tender green sprouts, pushing their way toward the light.

Emily is an award-winning science journalist and author of The Great Indoors: The Surprising Science of How Buildings Shape Our Behavior, Health, and Happiness.

Sign up for Inside Your Head 🧠

By Elemental

A weekly newsletter exploring why your brain makes you think, feel, and act the way you do, by Elemental senior writer Dana Smith. Take a look.

By signing up, you will create a Medium account if you don’t already have one. Review our Privacy Policy for more information about our privacy practices.

Check your inbox
Medium sent you an email at to complete your subscription.