A single session of exercise alters 9,815 molecules in our blood
By Gretchen Reynolds
When we exercise, the levels of thousands of substances in our bloodstream rise and drop, according to an eye-opening new study of the immediate, interior effects of working out. The study is the most comprehensive cataloging to date of the molecular changes that occur during and after exercise and underscores how consequential activity — and inactivity — may be for our bodies and health.
Already, of course, we have reams of evidence that exercise alters our metabolisms, muscles, genes, immune responses, hearts, stamina and almost every other organ and biological system within us. But only in recent years, with the development of sophisticated new techniques for counting and typing the thousands upon thousands of different molecules within us, have scientists been able to quantify more of the substances and steps involved in those processes.