A player requires Energy to use tools, fish, or engage in combat. Currently available energy is indicated on the player's energy bar, which reflects the decreases as a day progresses.Energy can be replenished up to its maximum by eating positive-energy food. Consuming negative-energy foods such as Sap or Void Mayonnaise reduces energy. To consume food, put it on the hotbar (the top row of inventory) and it. A notification in the bottom left of the screen will display energy and health gained by eating food. Typically, more expensive food provides more energy than cheaper food items.
The player starts the game with 270 maximum energy. Eating a Stardrop permanently increases maximum energy by 34 points. Eating every Stardrop available in the game permanently increases maximum energy to 508. Eating certain food can temporarily increase maximum energy, even beyond 508.
The player becomes exhausted upon reaching 0 energy, indicated by an X dialog bubble above the player's head and the notice "You feel sluggish from over-exertion." The player's movement speed is significantly reduced, and Fishing Poles can no longer be cast. Other energy-consuming tools can be used, but the player's energy level becomes negative. At -15 energy, the player passes out, ending the day. If the player passes out anywhere outside the house, the player will lose 10% of their money up to 1,000g.
Increasing energy back above zero (e.g., by eating food) will restore player movement, but the player remains exhausted for the remainder of the day. There is no in-game indicator of this lingering exhaustion, but it results in a 50% reduction in that night's energy restoration. This after-effect can be avoided by curing exhaustion, either by consuming Muscle Remedy, or (if married) kissing the player's spouse for the first time in the day.
There are a couple warning signs for imminent exhaustion. If energy is less than 20, any energy-consuming activity makes the energy bar shake and emit beads of sweat. When energy first falls below 15, a notice appears stating "You're starting to feel exhausted." These are warnings, not indicators of true exhaustion, and have no effect on player activities or overnight energy restoration.
Sleeping restores the player's initial energy level for the next day. Going to bed at or before 12:00AM normally restores energy to its maximum. If the player goes to sleep exhausted (or passes out), sleep removes the exhaustion, but energy restoration is reduced to 50%.
Energy restoration is also reduced if the player goes to bed after 12:00AM. The reduction is 2.5% per 10 minutes up until 01:00AM. After 01:00AM, it is 25% plus another 2.5% per 10 additional minutes. The player passes out at 02:00AM. For example, after retiring at 12:10AM, the player awakens with 97.5% of maximum energy. After retiring exhausted at 1:50AM, the player awakens with 12.5% of maximum energy.
If the new day's calculated initial energy level is lower than the player's actual energy level at the time he/she went to sleep, the player's energy level is left unchanged and not reduced.
The morning after a skill is leveled up, the player awakens with 100% of maximum energy, regardless of the sleep or exhaustion calculation.