Nearly half of Americans spend less than two hours outdoors in an entire week, according to a new national survey from the Nature & Health Alliance involving researchers at Texas A&M University.
Dr. John La Puma, a California physician and expert in nature-based medicine, has focused on the potential health impacts of spending less time outdoors.
In his book, “Indoor Epidemic,” he discusses how humans spend about 93% of their lives inside, which comes with a “hidden health tax.” He claims the remedy is a simple 7% outdoor prescription.
“Many people don’t realize that they’re inhibited from feeling as good as they can, because they’re exhausted even after a full night’s sleep,” La Puma told Fox News Digital.
“They need coffee to feel normal. They crash at 2 in the afternoon. They’re wired at night. They can’t go to sleep, but their labs are normal.”
“And they come into the office saying, ‘Why do I feel so exhausted?’ It’s the four Bs,” he said.
The ‘4 Bs’ caused by too much indoor time
No. 1: Bad sleep
Outdoor light can be many times brighter than typical indoor lighting, La Puma noted, making it a powerful signal for setting the body’s internal clock, or circadian rhythm.
“If you don’t set your body clock, your body doesn’t know what time it is, and it just goes to sleep whenever you can get to sleep instead of on time,” he told Fox News Digital.
Getting bright outdoor light soon after waking can help synchronize the body’s sleep-wake cycle and support the natural rise in melatonin later in the evening, according to La Puma.
He recommends spending about 10 minutes outdoors within the first hour of waking, without sunglasses.
No. 2: Burnout
La Puma uses the term “ultraprocessed time” to describe hours lost to screens, scrolling and other digital distractions.
“Ultraprocessed time is kind of like ultraprocessed food,” he said. “It’s not nutritious. It’s synthetic. It’s artificial. It’s ubiquitous.”
That includes time spent endlessly scrolling, he said, which can seem to simply “evaporate.”
La Puma argues that a person’s environment can contribute to burnout, rather than viewing it solely as a matter of willpower.
Spending excessive time indoors can lead to an overload of screen exposure, he said, as people often turn to the same devices for work, entertainment and relaxation. He noted that the body may not interpret screen time as true rest or escape.
“And equally important, no horizon. We are horizon-deprived as a species because indoors, we can’t see more than 20 feet in front of us,” La Puma said.
To combat burnout, he recommends getting up and going to the window and looking outside for a minute every hour.
“It relaxes your eyes, relaxes the muscles around your temples, reduces headache if you have it, improves energy and reduces fatigue,” he said. “That’s the beginning of being able to reverse burnout.”
Simply going outside during the workday can help to reverse burnout, LaPuma said.
“Your eyes need distance like your lungs need air.”
No. 3: Brain fog
People who spend the day indoors may notice that they feel mentally foggy by the afternoon, La Puma said, particularly in poorly ventilated spaces where carbon dioxide can build up.
Indoor CO₂ levels can climb above 1,000 parts per million in poorly ventilated spaces, and some research has linked elevated levels with reduced cognitive performance.
“So it’s not that you’re just making bad decisions in the afternoons — there’s a biologic reason for it,” La Puma said.
“What you need to do is cross-ventilate, but that’s tough to do in an office or conference room.”
The doctor said that getting outdoors gives the eyes a chance to focus at greater distances while providing a break from potentially stuffy indoor air. The EPA notes that concentrations of some pollutants can be two to five times higher indoors than outdoors.
No. 4: Belly fat
When someone’s body clock is out of sync, it can disrupt the body’s normal cortisol rhythm, La Puma said.
Cortisol, often called the stress hormone, naturally rises and falls throughout the day. Research has linked altered cortisol activity with greater abdominal and visceral fat, although the relationship is complex.
“Again, the way to improve your metabolism is to get daylight at the right time, in the right place, for the right duration — early in the morning especially,” La Puma advised.
“This will give you a bump in cortisol, which you want early in the morning to feel awake, and then it drops appropriately.”
The 17-minute dose
Most people spend about an hour outdoors each day as they walk from the car to the office, for example — but that’s what La Puma calls “incidental time,” not “biologically active time.”
To combat the four Bs, he recommends spending “intentional time” outdoors, “in a blue or green space,” for a minimum effective dose of 17 minutes a day.
“Be intentional with your time — look at the sky in the morning … to reset your body clock and watch the clouds,” the doctor advised.
For those who live in a big city and can’t see the sky, La Puma recommends looking at a distant rooftop, or looking through an open window when going outside isn’t possible. The goal is to focus beyond the confines of an indoor space.
“So 17 minutes a day is the minimum effective dose — that’s all it takes to begin to bend the curve on the four Bs,” he said.
“You can turn those minutes into medicine.”
