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.
When are you contagious? If you are infected with the flu, you are most likely to pass it to someone else from 1 day before symptoms start and up to 7 days after symptoms develop. Children may be infectious for longer than 7 days after symptoms start. Symptoms usually develop 1 to 4 days after you are infected.