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."

https://x.com/M_Stamatakis/status/1975783367577838072

Go so hard that you can't have a conversation and are in around 80% of HR max.

I think walking, and low intense ex is good for things like mental, reflection, etc. General refreshing. But if you need to get exercise in but dislike it, or don't have the time, HIIT is gooooood. :)