Three 10 minute exercise sessions a week of very easy cycling with a couple of all out sprints thrown in had significant impacts on insulin sensitivity and vo2 max. That is 10 mins including warm up and cool down.
The threshold for an effect from intervals gets lower and lower....
Of course I reckon they might well get a similar effect from an intense set of resistance exercise. Still tapping into the glycogen and all the same pathways and signals.
Everyone can do a few hard efforts each week and get benefit.