Stamina

This is an idea I'm bookmarking for later. Not yet fully baked. 

Stamina

• Sum your strength, constitution, and wisdom scores (not modifiers)
• This is your stamina
• It will be depleted by doing/enduring strenuous/stressful things, and you will not like it
• When you do or endure something strenuous or stressful, lose base of 1 stamina if you handle it as best it can be handled or base of 3 if not
• Add to base stamina loss any encumbrance penalty to movement speed, where each 5' loss of movement = 1 unit of penalty
• So climbing a talus-mantled slope using hands for balance and this having to stow equipped gear (1 base stamina loss) while wearing heavy armor (+1 loss) and carrying 60 pounds (+2 loss) is going to net you a total stamina loss of 4 this turn. 
• Stamina works to cap your max hp
• This replaces my previous hp-encumbrance linking rules
• In 4E, you are bloodied at half max hp. 
• So take that bloodied value and divide it by 2, rounding down 
• Add that to bloodied value to get your 3/4 hp value and subtract it from bloodied to get your 1/4 hp value. 
• Do the same with your stamina
• Now both stats (hp and stamina) are divided into fourths. 
• If you are not playing 4E, give  surges by HD (d4 = 8, d6 = 10, d8 = 12) + Con Mod. This is how many surges you can use per day. Bloodied value / 2 is the value of stamina and hp they restore. 
• Note when stamina enters a new "band" (e.g., now it's at 3/4 or less) and cap max hp at same value. 
• If you lose hp, you lose it starting from your current hp value. If it's capped at a lower level (like 3/4), you lose it starting from there. 
• When you spend a surge it restores hp and stamina according to their schedules.
• You can't go over your max.
• To spend a surge you must rest a turn and use ration/water, beauty/wonder of surroundings, or a social activity: singing, praying, talking about something. Describe what it is. Each surge costs a turn to spend. 

Alternately, to avoid having a separate resource pool:

Divide hp into 4 bands as above. 

Call them fresh (> 3/4 hp), winded (> 1/2 hp), bloodied (> 1/4 hp), weary (> 0 hp), exhausted (0 hp). These are called conditions. 

Keep a section of your sheet open for drawing Xs. 

When you do/endure something strenuous/stressful, mark a number of Xs = 1 + current encumbrance penalty. Roll with disadvantage if you're dealing w the thing in a suboptimal way. 

Then roll 1d20 + 1d[HD]. If you roll under the number of Xs, suffer the next worst condition (weary to exhausted, for instance), adjust hp if needed, and erase all Xs. 

When you regain hp to a higher band, better your condition accordingly. 

Use surges as above to regain hp if magical healing is not available or desired.