Cited research: Science Trans. Med. 2, 33ra37 (2010)

An analysis of 210 blood metabolites has yielded indicators of physical fitness.

Robert Gerszten and Gregory Lewis at Massachusetts General Hospital in Boston and their colleagues analysed blood samples taken from 70 people before and after a ten-minute run on a treadmill. The researchers found that, across the group, the levels of 21 metabolites changed during the run. Some of these metabolites are linked to cardiovascular fitness and faster running times in the Boston Marathon. Furthermore, fit volunteers showed signs of having more efficient fat metabolism than less fit individuals.

Feeding cultured cells a mixture of five of the 21 metabolites — glycerol, niacinamide, glucose-6-phosphate, pantothenate and succinate — rapidly boosted expression of the NUR77 protein, which controls glucose and lipid metabolism in muscles. H.L.