Riding on my bike in the morning is one of my best forms of simple,low-cost exercises available for me at the moment.
Cycling builds strength it's not just an exercise for the legs but to general perceptions.Builds stamina,even without your knowledge as once you start enjoying it you do not realise that you have gone further than original capacity. Its increase muscle tone is a slow but good way of increasing muscles.It's also reduces stress,cycling outside is a good way to be one with nature.