Imagine you’re on a boat. This boat has a sail, which you can put up or pull down. You’re on the ocean, and you’re trying to get to the sweet, sweet island of sleep. You can control the boat’s sail as much as you want. The only problem is: you can’t control the wind.
But this isn’t actually so bad. All you need to do is put the sail up to catch the wind when it’s moving you toward your goal, and pull it back down again when the wind is pushing you away from it. If you’re smart about how you move the sail up and down you can get to your island of Zzzs much faster than if you were just keeping your sail in one position and hoping to drift into place, or get randomly pushed towards it by the whims of the wind.
In this analogy, the wind is light exposure, and the sail is you controlling your exposure to it. Our apps have three lighting recommendations: Get bright light, avoid all light, and avoid bright light. Get bright light and avoid all light fit the analogy pretty nicely. Get bright light means put that sail up! Seize the momentum! Avoid all light means keep that sail down, and let yourself just drift for a bit, because seizing the momentum in this moment is actively hindering progress towards your goal.
Avoiding bright light is this gray area in between. Why does it exist? Because unlike being on a boat, where having your sail up or down doesn’t really come with any attendant restrictions on your activities, if we tell you to be in full darkness for 14 straight hours, that’s going to really put a damper on your life. You’re probably not going to want to do it for that long, even if it’s the “optimal” way to shift your body’s clock and hit your target.
So instead of telling you to do that, we tell you only to avoid all bright light during the hours when it’s most important. “Avoid bright light” hours are those other times when it’s best to keep the sail down and avoid the pushes of light, but it’s not as critical that you do it as other times. Think of these hours as times when the wind is blowing you away from the target, but only gently. Getting light, so long as it’s not super bright light, won’t keep you from your goals too long.
We hope you can use the “avoid bright light” times to keep your activity and light exposure more subdued, but not feel like it has to be zero. Use “avoid bright light” times to bank sleep for upcoming shifts, wind down for the day, and prepare to catch the breeze ahead.