If you're like many people, you may have decided that you want to spend less time staring at your phone. It's a good idea: an increasing body of evidence suggests that the time we spend on our smartphones is affecting our sleep, self-respect, relationships, memory, attention, creativity, productivity and problem solving and decision-making skills.
Until now, most discussions of phones' biochemical effects have focused on dopamine (多巴胺), a brain chemical that helps us form habits. Smart-phones and apps are designed to cause dopamine's release, with the goal of making our phones difficult to put down.
But our phones' effects on cortisol (皮质醇) are potentially even more alarming. Cortisol is our primary fight-or-flight hormone. Its release (释放) causes our bodies' changes, such as a jump in blood pressure, heart rate and blood sugar, that help us react to and survive acute physical threats. But by raising levels of cortisol, our phones may be threatening our health and shortening our lives.
The average American spends four hours a day staring at their smart-phone and keeps it within arm's reach nearly all the time, according to a tracking app called Moment. The result, as Google has noted in a report, is that "mobile phones loaded with social media, email and news apps" create "a constant sense of commitment bringing unintended personal stress."
"Your cortisol levels are increased when your phone is in sight or nearby, or when you hear it or even think you hear it," says David Greenfield, professor at the University of Connecticut School. "It's a stress response, and it feels unpleasant, and the body's natural response is to want to check the phone to make the stress go away."
But while doing so might comfort you for a second, it probably will make things worse in the long run. Any time you check your phone, you're likely to find something else stressful waiting for you, leading to another increase in cortisol and another desire to check your phone to your anxiety go away. This cycle, when continuously strengthened, leads to increased cortisol levels, which have been tied to an increased risk of serious health problems, including depression, obesity, high blood pressure, heart attack and so on.
