factors involved in viral infections

I'm an asthmatic, well-controlled without drugs. Still I get the occasional virus that used to kick off severe asthma attacks.
This virus follows the same pattern every time. My latest virus was definitely not "caught" from someone else.
It starts in my throat, a tickle, after a day or so, it moves up into my nasal passages and for two days have watery runny nose, then it goes to my chest. The virus seems to be active for about two weeks, then it is gone.
As soon as I felt the throat tickle, I: 1) eat very little, soups are good, and no sweets,  2) drink plenty, mainly water with powdered vitamin C dissolved, going slowly down my throat [even sipping vitamin C water at night, when dry],  3) get plenty of sleep, and 4) exercise, get out of the house, take some good walks.
This time the virus never got to my chest.

Question: Are there non-drug actions that can be taken that will affect power and progression of respiratory viruses, for good or bad?

Question: SL Johnston  (BMJ 1995; 310: 1225-9) and J Marin (J Infection 2000; 41: 69-72)
have found virus persisting in noses and throats of over 2/3 of symptom-free asthmatics tested. Are active viral infections are often set off by factors other than "catching" them from other people? Or by means other than "allergic triggers"? That is, do our lifestyle choices matter in setting off a viral infection?

Question: Is there a common "progression" of a viral respiratory infection? Do they have particular lifespans?

thanks, John
www.PracticalAsthma.net (100% non-commercial)

[National Jewish]

Acquiring and getting rid of infections are part of the functions of our immune system.  The course of action that you described is a good means of maintaining good health.  This state is important to maintain our immune system.  Those who are under a lot of physical and mental stress, not well rested or with good nutrition are at a higher risk of infection and affects of infection.

[SSS]

Sounds like the start of an allergic reaction to some environmental stimulant such as pollen or dust.  The sinus drains in the chest and that really sets you up for trouble.  Consider addressing potential triggers or take a decongestant to dry up the sinus from first sign of tickle.