Stamina in Red Dead Redemption 2 will drain when you are exerting yourself. If you’re running, climbing, or trying to swim your stamina core and bar will drain. The most common activity that will drain your stamina is running. Everytime you press A to run in Red Dead Redemption 2 you are draining your stamina bar. The stamina bar and car is represented by the lightning bolt icon.
When running with a full stamina bar and core you will see the bar around the lightning bolt slowly draining. When the bar gets to nothing you will see the stamina core start to drain. Once the core starts to drain you will lose stamina much more quickly.
To recover stamina you must eat food and drink elixirs and potions.
Elixirs and potions can be purchased at the General Store in numerous towns, but they can also be made by crafting if you’ve found the right recipes. These items can be crafted at campfire, as well as mobile campfires or any other campfire that you come across. Crafting can also be done when resting. Some potions and elixirs will fortify your stamina bar or stamina core. These items will make the stamina core or bar turn yellow and during that time it cannot be drained.
Food can also be purchased at the General Store but you can also cook food at a campfire. You can cook animal meat that you have killed while hunting to replenish stamina core.