a new study finds water exercise provides an effective aerobic workout.

canadian researchers had healthy participants do exercise tests on both land and water cycles -- gradually increasing their intensity.

their maximum oxygen consumption -- which measures the quality of the workout -- was almost the same on both types of cycles.

in fact, the participants' blood pumped more efficiently while in the water.

researchers say water workouts are a great alternative for people who are overweight, have joint injuries or suffer from arthritis.