Cortisol and your phone: what changes when you switch off
After five days off Facebook, an experimental study measured lower levels of the stress hormone cortisol in saliva, even though participants did not immediately feel better. The body reacts earlier than the feeling. Here is what is behind that, and where the limits of the study are.
The study
In 2018, Vanman, Baker and Tobin asked Facebook users to stay off the platform for five days (The Journal of Social Psychology). Result: lower salivary cortisol in the abstinence group. Cortisol is the body's central stress hormone; chronically elevated levels are linked with worse sleep and worse recovery.
Why the feeling lags behind
The fascinating part: subjective wellbeing did not rise right away, some participants even missed the platform. So if you take a phone break and feel restless on day two, you may quit at exactly the moment your body is already benefiting. That is an argument for rules that are not renegotiated every day.
The limits, honestly named
The study is small, the sample self-selected, and cortisol fluctuates for many reasons. That is why we deliberately say: linked with, not caused by. But it fits a bigger picture: in a randomized trial (BMC Medicine 2025), three weeks with at most two hours of smartphone time per day improved stress, sleep and wellbeing.
What you can do with this
You do not need five days of abstinence. A protected evening window in which the loud apps stay closed is the more realistic start, and that is exactly what the ctrl key is built for. All sources are in the research library.