The effect of prolonged exposure to extreme temperatures in Trail of Cthulhu is very straight-forward: Investigators are considered to be hurt, resulting in them suffering a +1 difficulty on all tests.
The designers of Eternal Lies had a desire to make exposure to extreme heat more mechanically interesting and they introduced a rudimentary heat track. I found their treatment interesting, but wanted something a little more robust (particularly when it came to treatment and recovery). These mechanics are specifically designed for desert travel.
(They’re also not exactly “untested”, but I don’t have a series of posts called “minimally tested”, so here we go.)
HEAT EXHAUSTION TRACK
0. Not suffering heat.
1. Can only make spends after first resting for 10 minutes (to gather their thoughts and spirits).
2. Difficulty of contests +1 (including hit thresholds).
3. Difficulty of tests at +1.
4. Can only make 1 spend per day and must make it in the morning after a good night’s sleep, before the day’s temperatures begin to rise.
5. Cannot make any spends.
6. Can only refresh 1 Health per day. If Heat Track would advance, it remains at 6 but character suffers 1 damage.
ADVANCING HEAT
Desert Travel: +1 Heat track per day. Characters who traveled during the day are considered to be under extreme heat conditions for the purposes of treating heat.
Camping: Characters who take a rest from traveling by camping for one full day are considered to be in favorable conditions for the purposes of treating heat.
Oasis: An oasis or similar place of significant respite may be considered “controlled conditions” for the purposes of treating heat.
TREATING HEAT
A given character can be treated for heat once per day.
First Aid/Medicine in favorable conditions to prevent advancement or reduce position on the heat track by 1.
First Aid/Medicine (difficulty 3 + heat track) in extreme heat conditions to prevent advancement or reduce position on the heat track.
First Aid 1 / Medicine 1 in controlled conditions to bring an investigator back to 0.
