If we all begin the same exercise routine tomorrow, some of us will become much fitter, others will get a little more in shape, and a few of us may actually lose fitness. Individual responses to exercise can vary that wildly and, until now, unpredictably. But a fascinating new study of more than 650 men and women suggests that the levels of certain proteins in our bloodstreams might foretell whether and how we will respond to various exercise regimens.
Using state-of-the-art molecular tools, the scientists began enumerating the numbers and types of thousands of proteins in each of the 654 people’s bloodstreams. Then they tabulated those figures with data about everyone’s aerobic fitness before and after their five months of exercise...The levels of 147 proteins were strongly associated with people’s baseline fitness, the researchers found. If some of those protein numbers were high and others low, the resulting molecular profiles indicated how fit someone was.
More intriguing, a separate set of 102 proteins tended to predict people’s physical responses to exercise. Higher and lower levels of these molecules — few of which overlapped with the proteins related to people’s baseline fitness — prophesied the extent to which someone’s aerobic capacity would increase, if at all, with exercise...Finally, because aerobic fitness is so strongly linked to longevity, the scientists crosschecked levels of the various fitness-related proteins in the blood of people enrolled in a separate health study that included mortality records, and found that protein signatures implying lower or greater fitness response likewise signified shorter or longer lives.
Taken as a whole, the new study’s results suggest that “molecular profiling tools might help to tailor” exercise plans. Someone whose bloodstream protein signature suggests he or she might gain little fitness from a standard, moderate walking, cycling or swimming routine, for instance, might be nudged toward higher-intensity workouts or resistance training.