If my memory serves me right, until my mid-20s, the most dreaded and contracted diseases then were Venereal diseases. Nothing really much about cancer, and AIDS was still unknown. For resurgent or re-surging diseases, I don't remember any except me contracting measles twice long after my first one during childhood. As for health and fitness, we used to play basketball all day, sometimes even into the night on concrete floors and hardly any of us had injuries that would side-line us for more than a week! There were also no energy or re-hydration drinks! Coke or other soft drinks were enough! There was no mineral or bottled water too.
Now we have to contend with deadly Influenza (Flu), and Pneumonia that has caused the demise of many who about to be discharged from the hospital! Tuberculosis (TB) is still much around. Cancer, AIDS and other debilitating diseases are causing much problems especially with the cost of health care! Sports athletes seem to be "weaker" because they get side-lined in spite of modern techniques, medicines and exercises to tune them up! There are all kinds of energy sports drinks and energy bars but don't seem to serve their purpose! Survival is now getting to be more challenging even with the advances in technology.
See what AH1N1 is doing now to the world!