This is always an important one in a Survival Horror (or any horror game) that lasts for long enough. All of that running, jumping, climbing and fighting is quite tiring, as are the emotional stresses of facing your Best Friend who is now the Infected Monster. But will the player characters try to sleep? And, more importantly, will you let them?
A lot of games have a few penalties that crop up the more exhausted the player characters get - and it can be fun to unleash them - but in most games increasingly irritable and tired characters can lose their lustre. There is, of course, a compromise. If they barricade themselves in tightly enough and take enough precautions (thus respecting the danger they're in) then it makes sense to let them sleep off some of them penalties.
It can also up the tension whenever a period of Nothing Bad Happens occurs and can boost the unpredictability factor of your game if they manage to get a good night's sleep in. Heck, one trick is to see just how much they're taking their nap time for granted. The more they anticipate a good night's sleep, the less likely you should give them one.
In my caving game, there was actually an easily defended cul-de-sac built into the caving structure not far from the actual temple. It was perfect for them to sit down, eat, and nap enough to remove their penalties. It also kept them distracted while the Enemy collapsed their escape route so that they could only move forward. It worked out quite well and certainly gave them enough time to really get into that survivalist mentality.
Of course, in the end, it's all up to you, the pacing of your game, and the length of the survival horror. If it's only meant to be a few hours in-game, or a single night, this may not come up whereas in a game that spans multiple nights it's more likely to become an issue.
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