I had to edit the title to fit the HN character limit, hopefully I got the gist of it.
One of the researchers tweeted:
"Pretty much the whole industry (incl. @Google Fit @Apple Fitness+) assume that 1 minute of vigorous activity = 2 minutes of moderate activity, in terms of heart health value. Our UK Biobank analyses show that they may be far off, e.g. 1 minute of vigorous = 9.4 minutes of moderate = 94 minutes of light intensity activities, in terms fo type 2 diabetes risk. 1 min of vigorous = 7.8 mins of moderate = 73 minutes of light, in terms of CVD risk."
And the causual mechanism is?
Hopefully it's not a reversed "healthier people do more vigorous activity".