After living in China for 4 years, my allergies are gone, and while I got sick here a lot then, I have not had a serious cold in 6 years. The allergy experienc

After living in China for 4 years, my allergies are gone, and while I got sick here a lot then, I have not had a serious cold in 6 years. The allergy experience mimics many other people who spent time in Asia. The no colds - I think it's related, but most people do still get sick. I used to get terrible colds every few months my entire life. I can now scuba dive because my ears aren't constantly damaged by frequent sickness and fluids. My theory has always been that allergies are a symptom of an under-utilized and under-exercised immune system. Our bodies are designed to be under constant attack. Much like the US is unable to resist invading countries when the world is at peace, our immune system can't stand a sterile body with no foes.