Thoughts on Dehydration and Starvation
I did a precursory scan (read: “I googled it”) and did not find any gritty, simulationist rules of dehydration or starvation. I’m looking for something that is not too complicated to keep track of on the side, but realistic enough to motivate the players to pay attention.
What I have come up with should fit any system where attributes are rated from 1 to 20, with 10 being near-average, and an attribute that is at least equivalent to constitution. (I had Chaosium and Morrow Project in mind, but D&D and all sorts of other games fit this bill too.) I am basing these rules off of the “survival rule of 3″ concept–3 weeks without food, 3 days without water, 3 minutes without air. (Although we will be ignoring the air part in this post.)
For each week a character goes without food, halve their Con score (round down.) A character with an average score of 10 has 3 weeks before they hit a Con score of 1. To make this a little more realistic, you can take the amount of points a character will loose during that week and divide it over seven days. (So the first week a character with 10 Con is going to lose 5 points, about 0.7 a day. The next week they will lose 3 points, or about 0.4 a day.) If you assume 3 meals a day, you could divide the loss by 21 to find out Con lost per meal.
For each day a character goes without water, halve their Con score (round down.) A character with an average score of 10 can last about 3 days before they hit a Con score of 1. Like starvation, you can break this down to hours by dividing the day’s loss by 24. If you aren’t looking to count hours, you can break it down into quarters of a day (applying the loss at 6 am, noon, 6 pm, and midnight; or maybe breakfast, lunch, dinner, and sleep.)
Important note: dehydration does not stack with starvation. Keep track of Con loss separately from both causes, but use the lowest of the two values. In this way, a character that alleviates their worst condition can only improve to their next-worst condition.
A character regains lost Con through consumption. A character regains their last lost increment or starvation when they eat a meal, and of dehydration when they drink liquid. This should be a sizable amount of a given substance (perhaps half a pound of food, or 8 ounces of water.) A character can only make this recovery once per day for starvation, or once per hour for dehydration.
These rules assume no food for starvation and no liquid for dehydration. If a character is consuming less than what they need a day, they can extend their life a little. Take the fraction of subsistence the character is consuming, inverse it, and apply it to the current loss countdown. In other words, if a character is eating half their daily food needs, double the amount of time before Con loss occurs.
That works.