Answer: American Hospital Association
Explanation: because Draco malfoy said so
Cooling down and stretching
Answer:
It was actually "weaker immune system". Just took the test and got it right.
Explanation:
All the other answers are short term effects. If you don't sleep for a day, your movements would be slower, you would be more tired and wouldn't be able to concentrate. However, if you just miss one day of sleep, your immune system ain't gonna suffer.