Well, there are a variety of theories about this, but the main one that I believe is that those with dispositions which are positive and those who feel more purpose in life tend to be the ones who do not fall ill all that often. This has been speculated on for a long time by modern science, and the theory seems to prove true when researchers do surveys of people asking them about their general feelings toward life, their positive and negative feelings, how they feel about their place on this earth etc, and then combines it with how often they feel sick or get sick.

Another theory is that those who tend to fall ill more often and be more susceptible to catching things have a poor diet or don’t get enough of the vitamins that help to strengthen the immune system. There are also theories that some of us are just born with stronger immune systems, or that we just developed more of a strong response over time to these invaders.

Some think that stress levels and depression (which tend to go hand in hand) have a lot to do with us warding off colds and flus. Those that have less stress may be less vulnerable to the latest bug, while those that have tons of stress and release a lot of stress hormones may be depleting their immune system. Also, lack of sleep is a factor here because lack of sleep leads to stress, and also suppresses our immune systems, so sleep is absolutely vital to keeping our front line defenses against sickness in top shape.

I’ve always believed that certain vitamins, especially vitamin c ester, have helped me ward off colds and flus over and over again. Sometimes I’ll even find that I start to get a bit of the sniffles, and then it’s like it just disappears spontaneously without ever having taken a complete grasp on my immune system, lungs, and overall feeling. But it is rare that I get a full on cold or flu. I’ll admit, I still get sick, but it seems like the severity is very short lived, and I attribute that partly to getting lots of vitamin C in my diet.