People who fly will notice that once they land, they feel incredibly tired and lethargic. This happens even if the flight was long enough to have a nap. Have you ever wondered why flying makes you feel tired? There could be several factors at play.
The air that is circulated into the airplane cabin is brought in from the outside atmosphere. The air that exists so high in the atmosphere is surprisingly void of moisture which means that the air you breathe during a long flight is dry. Dry air can cause you to develop dehydration. Dehydration causes lethargy and tiredness because it means that your blood volume has been reduced and isn’t providing necessary oxygen to your muscles and organs. The best way to combat this type of exhaustion is to drink plenty of water while in flight.