> For the complete documentation index, see [llms.txt](https://sense4fit.gitbook.io/whitepaper/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sense4fit.gitbook.io/whitepaper/experience-energy-power-ups-and-mystery-boxes/energy.md). # Energy Energy is required to start a workout and is paid out daily based on a user’s rank, and is required in single mode challenges, but is not required to participate in group and team challenges. Energy can also be gained by watching ads, but also through power-ups and referrals. If a user brings in more friends to the app, they can replenish their energy levels faster, increasing adoption of the project. Below we have added a table explaining how Energy can be used, depending on the type of workout. As seen, lower ranks are only allowed to train for a maximum of 45 to 60 minutes a day, meaning that they could train once or twice. As you grow throughout the ranks, users are allowed to train up to twice a day, thus yielding maximum rewards.