Common Cold is responsible for highest number of working hours lost.
Our body consists of about 72% of water. Heat and cold have the same effect on the water inside our body as on the water outside. Our body also has an air conditioner as well as a heater. In summer or in winter, it maintains the temperature of 98.6o F (36.9o C). The water in our body gets heated during the day due to activity and due to outside temperature, while during the night, it cools down, creating moisture in the lungs or head. In Nature, it is thrown out in the form of dew. In the case of our body, it is thrown out by sneezing or watering of the nose in the morning.
Normally the body tries to throw out excess water through sneezing and running of nose twice in a year. The phenomenon lasts for 3 to 5 days each time.