Activity and insulin resistance show opposite muscle gene links

In an observational study of 263 Finnish individuals, researchers analysed gene expression across 168,309 muscle nuclei and chromatin accessibility, which measures how open DNA is to being read, across 242,069 nuclei. Both higher total physical activity and lower insulin resistance were associated with higher proportions of Type 1 nuclei and lower proportions of Type 2x nuclei. Lower insulin resistance and higher activity were also linked to higher expression of energy metabolism genes and lower expression of signalling pathway genes across muscle fibre types. When adjusted for both traits in the same model, physical activity and insulin resistance appeared to have inverse and partly independent directions of association.