Lol at druidh – and he’s right.
In terms that I can’t understand it also develop’s your capileries in your muscles and small oxygen branches in your lungs whilst resting you muscles and lungs. As Druidh hints at it rests your head also.
The net result is you can ride longer/further/faster/more efficiently in the seasonal months.
Its also referred to recovery training, zone 2 or base training. I did a 50m Z2 on Sunday as I’ve started my base training for the winter. Riding with an HRM in Z2 is one way of burning fat also.
There’s a good page in the last Cycling plus Mag which gives 4 winter workout plans that explains this – this being one of the workouts.