Abstract/Summary

The composition and functionality of the gut microbiota (GM) changes throughout the life course. As we move into older age, it starts to shift towards a less healthy one, which may lead to an imbal- ance in the GM community. Strategies that can reverse age-related dysbiosis are an important part of healthy aging. Little is known about the GM composition of older adults with di erent physical activity (PA) levels and whether it might contribute to healthy ageing. The aim of this study was to compare the GM composition of older adults with di erent PA levels and assess if it is associated with healthy ageing. 101 participants aged between 65–85 years undertook anthropometric measures, a 6-min walking test, wore an accelerometer for 7 days and provided a faecal sample. Faecal GM composition was analysed using 16S rRNA sequenc- ing. We found that those who ful lled the WHO/UK PA recommendations had higher relative abundance of several health-related bacteria such as Lactobacillus, F. prausnitzii and Roseburia intestinalis and lower abun- dance of disease-associated bacteria such as D.piger or Enterobacterales when compared to those who did not reach PA recommendations. These ndings suggest that PA might improve the GM composition and has the potential to, at least partially, revert age-associated dysbiosis and promote healthy ageing.