SolWalks

SolWalks is a tool that helps you develop a habit of taking outdoor walks at the time intervals most efficient to synchronize your circadian clock.
In the early 2000s, a type of photosensitive cell called ipRGC was discovered in the human eye. These cells are involved in registering the ambient light illuminance on a subconscious level. It is proved that this signal is the main way to synchronize the body's circadian clock. Spending most of the day indoors and using artificial light frequently can lead to desynchronization of your circadian clock, impaired sleep, increased fatigue, and a depressed mood. SolWalks has a built-in light meter that will allow you to assess the ambient light illuminance, in a similar manner as it happens on a subconscious level. The app is integrated with HealthKit. It visualizes your HealthKit walks data, raising your awareness of the time you spent outside and motivating you to stick to the habit of walking at the optimal time of the day.
Terms of use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/