By Dan Garner

A new study from the University of Basel in Switzerland had 29 healthy test subjects expose themselves to varying levels of blue light for one full hour in the evening, but then stop 50 minutes prior to getting into bed.

Here's What Happened

1. Higher levels of light exposure suppressed melatonin release 14% more than the lower levels.

2. That seems significant, until it was identified that melatonin levels were back to normal 15 minutes before they got in bed.

3. Regardless of light exposure intensity, self-reported sleep quality scores did not suffer.

The Takeaways

1. If the participants tried to go to sleep immediately after light exposure (like many do when they bring their phone to bed) it would have likely negatively impacted sleep quality to a significant degree.

2. Although phone use can be cautioned against for a variety of reasons (e.g. if it prevents you from "winding down" or if you don't use it in "dark mode"), if you discontinue the use within an hour of bedtime it is likely your sleep chemistry will stabilize before getting in bed.

3. Bright light during the day decreases your susceptibility to light in the evening. Light exposure upon waking plays an irreplaceable role in how well you sleep in the evening.

Bottom Line

The common coach's recommendation of abandoning your phone doesn't work with 90%+ of the population. Just like an extreme diet isn't sustainable, an extreme recommendation of asking someone to abandon something they are quite literally addicted to isn't realistic.

However, using it in a dark mode in the evenings, getting sunlight upon waking, and turning it off around one hour before bed is a very reasonable and excellent way to start sleeping much better.

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