The autonomic nervous system (ANS) regulates the functions of our internal organs (the viscera) such as the heart, stomach and intestines.
The flu is contagious a day before and five days to a week after its onset. Young children, people over 65, those with compromised immune systems, and people with a terminal illness are at risk of death from the flu.
The flu is also contagious the day before the first symptoms begin. The person remains contagious for 5 to 7 days, as long as the body is producing new mucus, and they are also contagious as long as they have a fever.