Interesting observation by a student I have tutored for three or more years: I am the only one of his tutors who has not cancelled because of illness. (I might have been sick and cancelled once or twice. It’s just so rare he does not remember.) Oh, and some of the others have not tutored him as long as I have. (Someone else who does Paleo has been sick once, but probably because of lack of sleep in a busy time at work. All the others have been sick multiple times.)
The difference? Diet and lifestyle. I don’t have some great immune system: I used to get sick more. I eat Paleo, get some exercise, and get good sleep (mostly). In other words, I just do what a human being needs to do to excel. I don’t deny my nature. Takes time and effort to make things this way, yes, but it’s worth it.
Life is worth it. Life is its own justification. Do it for yourself. Do it for those you love.