I think it is the combination of the amazing beach views, the smooth riding path free of cars, the youthful feeling that you get when riding a bike along with the usual endorphins that come with some cardio that makes this a great workout.
I have yet to regret any of my biking workouts. Even when I'm tired, I am always in a much better mood once I breathe in the sea air. An unlike going to an indoor gym, there are all types exercising at "my outdoor gym". Young, old, fat, thin, athletes and tourists all walk, run, skate and bike in harmony. No one tries to pick me up. There are no lululemon fashion shows. It is just me and the beach and my bike.
The best part about this workout is that I don't have to haul a bike to the beach. I have been doing "bike sharing". All over South Florida, there are bike sharing stations popping up. In Broward County, where the amazing Hollywood Beach Broadwalk is located, there are B-cycles.
You can either rent by the day ($10 an hour) or pay $45 for a year-long membership. With a membership, the first 1/2 rental every day is free and it is $1 for every half hour after that. You just swipe your credit card if you are not a member. With membership, you walk up to a bike, place your membership card on a sensor next to it and off you go.
I love not having to lift a heavy bike on and off of a bike rack. I love not having to worry about maintaining a bike. I just walk up, ride and then put it back. The bikes are in great condition and feature huge baskets with funny signs on them.
Even when it gusting 30 m.p.h. and it feels like you are riding against a brick wall (like today!) it is always a good, fun workout. If you are near Hollywood Beach, I'd highly recommend it. Just save a bike for me!