Is it fair that fit people get more from exercise than less fit people? The Scientific American reports on new study, published in Science Translational Medicine,
that reveals vast biological differences among
more- and less-fit individuals. Sciam reports that the researchers measured more than 200 metabolites, small chemicals involved in the
body’s metabolism, and found that people who were more and less fit
had vastly different metabolite profiles across a wide range of exercise durationsâ€â€from 10 minutes of treadmill running to completion of the Boston Marathon. Even in those who exercised
for just 10 minutes, their metabolite profile was still being affected
an hour later, which suggests, as one researcher said, that “exercise sparks long-term signals
[and] that we’re just beginning to scratch the tip of the iceberg.”
Two big differences noted by the researchers: Glycerol levels increased much more in fitter people (as assessed by
peak oxygen uptake). In leaner subjects (with body mass indexes, or
BMIs, less than 28), levels of niacinamide, a metabolite that increases
sensitivity to insulin, increased more than twice as much as it did in
larger individuals.