[Caduceus]

Over that short a distance, probably equally efficacious. Weight loss, improved cardiovascular performance and general exercise tolerance occur when an individual pushes their body for more than thirty minutes at a pace that just makes them able to carry a conversation.

My general advice to folks is to try the 20 minute challenge where they run/bike/swim for twenty minutes at a pace they can maintain three to five times per week for two weeks. After the two weeks (establishing the habit of working out), add two minutes per week.

It is critical to
a.) not push yourself too hard initially.
b.) find a buddy to keep you on-track with your exercise schedule.
c.) stop if you have pain.
d.) wear comfortable and appropriate clothing for the exercise (wearing multiple layers of clothes to help "sweat off the pounds" can be dangerous)
e.) hydrate hydrate hydrate before and after exercise - water and some sports drinks not sodas/coffee

Obviously if you have medical problems, consult your doctor first. He/she may recommend a stress test on a treadmill before initiating any new exercise regimen.