This is a meta-analysis of many other studies of varying quality. There are many limitations, including the inclusion of a study that did not show effect , excl

This is a meta-analysis of many other studies of varying quality. There are many limitations, including the inclusion of a study that did not show effect , exclusion of people with heart disease problems etc. They are described in their discussion section here: https://bjsm.bmj.com/content/early/2019/09/25/bjsports-2018-100493 https://bjsm.bmj.com/content/early/2019/09/25/bjsports-2018-... this seems to put a few grains of salt in this all-or-none preclamation