Me and Jimmy D have been training to be in the SAS, despite the fact that we drink a few pints and are in our mid-thirties. Part of this is fatness / heart-attack avoidance, part of it is just because it produces statistics.
We’re currently doing 5 miles fairly steady. Would like to do more but that starts eating into quite a bit of time, so 5 miles is the limit. The 7mph peaks are where Jimmy’s too lazy and I’ve gone on my own.