17 Minutes Outside: A Doctor’s Prescription for the Indoor Epidemic

Dr. John LaPuma, a physician and trained chef, spent years reading 2,200 studies to understand something he felt in his own bones: that being indoors was making him sick. The numbers he found are stark. The average person spends 93 percent of their time inside. Only 7 percent of time is spent outdoors, and much of that is incidental—walking to the car, picking up a delivery, phone in hand. LaPuma calls this the indoor epidemic, and he argues it is driving insomnia, anxiety, immune dysfunction, cognitive fog, and even premature death. His prescription is surprisingly modest: 17 minutes a day in a green or blue space, taken intentionally, can function as a form of medicine.

The Seven Percent Solution

The core mechanism LaPuma describes is that our biology evolved outdoors, and indoor environments deprive us of natural cues our bodies need to function properly. The minimum effective dose, he says, is two hours per week—about 17 minutes per day—spent in what he calls green spaces (areas with plants and trees) or blue spaces (near water, preferably running). This is not the same as incidental outdoor time. It must be intentional: you go outside with the purpose of being in a natural setting, even if that setting is your front yard, a neighborhood park, or a community garden.