HIIT training found to reduce the ageing process due to the changes it creates at cell level.

Mayo Clinic researchers found there’s nothing like HIIT to stave off the aging process, thanks to changes it creates at the cell level, effects that can’t be achieved with any kind of medicine. What’s more, as positive as the changes were for younger people studied, they were even greater among people over 65.

https://www.usnews.com/news/health-news/articles/2019-06-18/is-interval-training-the-fountain-of-youth