I think cycling has to be taken in a different context to other forms of exercise as it is fundamentally a means of transport, unless you're one of those yuppie losers falling in love with the Peloton 'hunk'. Plus it has mechanical advantage, meaning that not a great deal of exercise will easily get you seven miles, so it's difficult to really get proper exercise if you're restricted to going round the block - it would be easier to walk. Just in case anyone thinks I'm sticking up for Boris - but even that fat lump can't change the laws of physics.