Doctor Explains What Spending 93% of Your Time Indoors Could Be Doing to Your Body

Most people don’t wake up and think their biggest problem is that they spend too much time indoors. They blame stress, work, poor sleep, anxiety, or simply getting older. Yet Americans spend around 87% of their time inside buildings and another 6% inside vehicles, leaving surprisingly little time outdoors. Dr. John La Puma believes that this modern routine may be contributing to a growing collection of problems that people struggle to connect: feeling exhausted during the day, wired at night, unable to focus, and strangely unrested even after sleeping.

La Puma describes the pattern as “digital obesity,” a biological state in which the brain’s alerting system receives far more stimulation than it can comfortably process. Screens, artificial light, constant novelty, and ongoing cognitive demands can keep the nervous system switched on for much of the day. Meanwhile, some of the conditions humans historically experienced every day, including natural daylight, genuine darkness, movement, distance vision, and regular outdoor exposure, have become increasingly limited. The result, according to his argument, is a serious mismatch between modern life and the conditions the human body developed around.

The Brain May Never Get a Proper Break

“What’s getting overfed is the brain’s alerting system,” La Puma explains. Modern life gives the brain an almost endless stream of information to process, from work emails and notifications to videos, social media, and breaking news. Even when people are technically resting, many remain mentally engaged with a screen. The body may be sitting still, but the nervous system can remain active as it processes new information, responds to alerts, and anticipates whatever appears next.

Doomscrolling may be one of the clearest examples of this problem. A person can spend hours consuming stressful or alarming information without reaching any genuine resolution. The brain remains alert because there is always another post, headline, or video waiting. La Puma links this broader pattern of constant stimulation with issues including lower heart rate variability, elevated evening cortisol, delayed melatonin, shallow sleep, impaired glucose control, and weight gain. People may end up feeling tired but unable to properly relax, creating a frustrating cycle where exhaustion and restlessness exist at the same time.

This does not mean every case of poor sleep, anxiety, or fatigue can be blamed on spending time indoors. These symptoms can have many causes. However, La Puma’s argument is that modern routines often combine several potentially stressful factors at once. Long periods of sitting, constant close-up screen use, artificial lighting, limited movement, and little exposure to outdoor environments can create a daily pattern that leaves very little room for the nervous system to reset.

The problem may also be difficult to recognize because indoor living has become completely normal. Someone can wake up inside, commute in a vehicle, work inside, exercise in a gym, order food, watch television, scroll through social media, and return to bed without spending meaningful time outdoors. There is no dramatic moment when the connection to daylight and open spaces disappears. It simply becomes a smaller and smaller part of everyday life.

Why the 93% Figure Is So Alarming

The figure is based on time-use research summarized by the U.S. Environmental Protection Agency, which estimates that Americans spend about 87% of their time indoors and another 6% inside vehicles. For many office workers, remote employees, and students, the amount of time spent outside may be even lower. Modern technology has made it possible to work, communicate, shop, exercise, and entertain ourselves without needing to leave a building.

La Puma argues that the precise percentage is less important than what it represents. Human biology developed around regular changes in light and darkness, movement through different environments, and the ability to focus on objects at varying distances. Modern life often replaces those experiences with climate-controlled rooms, artificial light, and screens positioned only inches or feet from the face. The body has changed far more slowly than the environments people now spend most of their lives in.

One of the simplest differences is vision. Looking at a phone or computer requires sustained close-up focus, while spending time outside naturally exposes the eyes to longer distances. A walk through a park, a view across a street, or simply looking toward the horizon gives the visual system a different kind of experience. La Puma believes this distance vision is one of several natural inputs that modern indoor routines have reduced.

The same pattern applies to light. Natural daylight changes throughout the day, while indoor environments can keep people under similar lighting from morning until evening. Darkness has also become increasingly rare because screens and artificial lights remain available until the moment people try to sleep. The concern is not that indoor spaces are inherently harmful. It is that spending nearly all of life inside can remove important environmental signals that help regulate how the body functions.

The Suggested Amount of Outdoor Time Is Surprisingly Small

La Puma is not suggesting that people abandon modern life and spend their days living in the wilderness. His recommendation is intentionally modest: around 7% of a person’s time outdoors. That works out to roughly 100 minutes each day, although he also describes two to five intentional hours per week as a useful target. The idea is based on a minimum effective dose rather than a complete lifestyle transformation.

“The benefits rise quickly at low doses and then level off,” he says. According to the approach described in the source material, regular outdoor exposure may help support better sleep timing, steadier mood, sharper focus, and improvements in metabolic markers. The goal is not to turn every person into an outdoor athlete. Short periods of purposeful exposure can provide daylight, movement, visual relief, and a break from the highly stimulating conditions that dominate much of indoor life.

Morning light is particularly important in La Puma’s approach. Exposure to daylight earlier in the day can help provide the body with a clearer signal about the timing of the day. That signal is connected to the sleep-wake cycle, which may explain why people who spend their mornings in dim indoor spaces and their evenings under bright artificial light can struggle with sleep timing.

Outdoor time can also become more useful when it combines several healthy inputs. A walk with a friend may provide movement, daylight, conversation, and a break from work. Sitting near water or beneath an open sky may offer a change from enclosed environments. The intervention sounds almost too simple in a culture surrounded by expensive wellness products, but that simplicity is part of La Puma’s argument.

Doomscrolling Outside May Not Give You the Same Benefit

Taking a phone outside does not automatically mean the nervous system has stopped receiving constant stimulation. A person can sit in a park while scrolling through stressful headlines, arguments, notifications, and videos. They are physically outdoors, but much of their attention remains connected to the same digital environment they experience inside.

La Puma’s broader point is that outdoor exposure works best when it changes the inputs the brain is receiving. Natural daylight, physical movement, longer-distance vision, and a quieter attentional environment can provide something that constant screen use does not. Doomscrolling, on the other hand, can continue feeding the alerting system even when someone is technically sitting outside.

That does not mean technology has to be completely removed from outdoor life. People may still use their phones while walking, meeting friends, or spending time in a park. The difference may come down to whether the device is supporting the activity or replacing it. Checking directions during a walk is different from spending the entire walk consuming an endless stream of alarming content.

For people who find it difficult to stop scrolling, even a short period without constant digital stimulation could change the experience of being outdoors. The goal is not perfection. A person does not need to become completely disconnected from technology to spend more time in environments that offer daylight, movement, and visual variety.

Nature-Based Care Is Already Used Around the World

La Puma argues that the benefits of outdoor exposure should not be dismissed as vague wellness advice. The evidence he points to spans areas including sleep research, metabolic health, mental health, and cardiovascular disease. The source material also notes that targeted daylight exposure can affect sleep timing within days, suggesting that some changes to daily routines may produce noticeable effects relatively quickly.

Nature-based prescriptions have also become part of healthcare approaches in countries including Japan, South Korea, the United Kingdom, and parts of Europe. These programs differ from place to place, but they share a similar principle: spending time in natural environments can be incorporated into efforts to support physical and mental wellbeing. The idea is far from a new invention, even if it can sound unusual in a culture heavily focused on products and technology.

La Puma makes a blunt observation about why simple outdoor interventions may receive less attention than expensive solutions. “You can’t patent sunlight,” he says. Modern consumers can buy sleep trackers, supplements, specialized lighting, fitness subscriptions, and countless other products designed to improve health. Walking outside in the morning is much harder to package and sell.

That does not mean sunlight or outdoor time should be treated as a cure for every health problem. The point is more practical. If modern routines have removed many of the environmental conditions that once occurred naturally, restoring some of those conditions may be worth considering alongside other approaches to health and wellbeing.

Going Outside Still Requires Common Sense

La Puma is realistic about the fact that outdoor conditions are not always safe or comfortable. People dealing with wildfire smoke, severe heat, heavy pollution, or other environmental risks should not simply force themselves outside to meet an arbitrary target. The goal is targeted exposure that fits real conditions rather than following a rigid rule.

On smoky days, the source recommends keeping outdoor time short. During periods of extreme heat, going outside earlier or later may be a safer option. In heavily polluted areas, green spaces and areas near water may sometimes offer a better choice than spending time beside busy traffic corridors. Access also varies dramatically, and not everyone has a large park or quiet natural area within walking distance.

The good news is that the proposed intervention does not require a perfect setting. A local park, a quiet street, a backyard, a balcony, or a walk around the neighborhood may offer opportunities for daylight and a change of environment. People do not necessarily need to hike for hours or travel to a remote location.

“The tools are simple,” La Puma says. “The gap is awareness, not willpower.” That may be the most difficult part of the entire issue. Indoor living has become so deeply embedded in modern routines that many people may never consider the possibility that they are missing something their bodies have always depended on.

The Simplest Health Habit May Be Waiting Outside

People looking for more energy or better sleep are often encouraged to download another app, buy another device, or build another complicated routine. La Puma’s argument points in a much simpler direction: spend more intentional time outside and pay attention to what happens.

For a population spending almost all of its time indoors or inside vehicles, the outside world may have become one of the most overlooked parts of a healthy routine. Opening the door for a regular dose of daylight, movement, and open space could be a far more significant change than it first appears.