Exhausting actions and harsh environmental effects that chip away at your energy reserves cause Stamina Drain. Once your body surpasses its natural limits, you make a Stamina check. As long as the cause of the Stamina Drain persists, you must repeat the Stamina check at regular intervals, and the DL increases each time. A failed check moves you one stage down the Knockout Track.
Some effects that cause Stamina Drain are tiring, meaning that your own physical exertion is sapping your energy. Once you stop the taxing activity, the penalties remain until you get a good night's sleep or engage in responsible stimulant use. Other effects are lethal, meaning that a lack of something your body needs is causing you to black out. The penalties will continue to accumulate as long as the effect persists (but as soon as the effect is no more, the penalties vanish). Not even sleep will remove penalties caused by lethal Stamina Drain. Once you reach stage 5, if the effect persists and you fail another check, your body gives up and you die outright.
Any effect in this game that imposes Stamina Drain will list the initial DL, the frequency of Stamina checks, the amount the DL increases each time, and whether the effect is lethal or tiring. For example, the suffocating condition described below causes Stamina Drain (DL 15; +1 every round; lethal).
Stamina Drain is cumulative. For example, if your character is both starving and under-dressed in the arctic, you have to make one daily Stamina check and one hourly Stamina check. If you fail either, you move one stage down the Knockout Track.
The following entries describe various effects that cause Stamina Drain.