I have a character who has been traveling on foot through central Germany for some days. How many miles per day? How many days? How is he dressed? What condition are his feet in? How fit was he when he started? Any underlying medical conditions? What is his age? All of this effects his baseline on the night in question.
He is young and was in moderate but not great health when he started. He's been traveling for anywhere from a few days to a week with minimum amount of food. Don't know that I can tell you how many miles a day, but he's traveling to get where he's going as quickly as he can, so he's not dawdling. He's traveling as steadily as his body will allow. It's actually not a night in question, but a day. He falls asleep in the late morning.
It's early December. Can be anything from somewhat mild to below freezing, depending on the weather pattern. The colder the temperature and the less properly prepared he is, the greater the consequences.
Yes, I suppose this is the part where I have a bit of leeway. I have a small range of possible temperatures I can work with.
He's exhausted, hungry, dehydrated. It would be unlikely that he's dehydrated. Absent a medical condition or age (elderly people don't tend to drink enough), dehydration occurs predominantly from either heat or lack of water. Germany has enough streams and other water sources so that's not a problem. It's possible that someone could gradually dehydrate themselves from the exercise, but especially with hunger, he'd probably be drinking quite a bit.
He's been getting as much water as he can, but doesn't have a means of carrying water with him. I didn't mention that he woke up this particular morning hungover.
If he's dehydrated to any significant degree, he would be disoriented and probably imagining things. Especially combined with his hunger.
Hunger is going to be a question of how many calories he's been ingesting. Is he on zero calories, 500, 1000, 2000, or just the level of hunger that most people feel with this level of exercise? Besides generating energy for walking, calories are what we use to provide heat. It's possible that his core temperature has dropped below 98.6. It could have dropped significantly before he even stops.
He has sporadic access to food, so he hasn't been going days without food, but he has been going days without adequate and nutritious food.
It starts to rain and he pulls a blanket over his head and crawls under some branches to take shelter. He falls asleep. Does he suffer anything from the exposure to the cold? Any hypothermia or frostbite or anything else? Depending upon your setup, anything from a nice, deep, relaxing sleep to death rather quickly from hypothermia. Pulling the blanket over his head and getting under the trees doesn't sound like he's too disoriented, so he probably isn't dehydrated and not too hungry.
My guess is he'd sleep the sleep of the dead, but probably with no serious effects.
Great. 'The sleep of the dead' works for me. You're exactly right in that he isn't disoriented at all when he crawls under the trees with his blanket. I was just concerned that I would push the bounds of realism if I had him wake up after that with no ill effects.
Thanks for the great questions!
Best of luck,
Jim Clark-Dawe
He was drinking the previous night in a very misguided effort to stay warm and woke up the morning in question feeling colder and more dehydrated because of it.