I just saw this video being posted on the French forum Esprit Apnée, and thought it may interest you too.
Ludovic Diligeart (France) created a Guinness world record of 702 m on a submerged exercise bike in a single breath. Well, it is already quite old (from July 2003), but I thought the title sounds funny and sensational enough to post about it now
Well, actually it is not really a dynamic record, since the bicycle was stationary, but then again who cares 
Blinkx Video: Underwater Exercise Bike Cycling - Distance
Ludovic Diligeart (France) created a Guinness world record of 702 m on a submerged exercise bike in a single breath. Well, it is already quite old (from July 2003), but I thought the title sounds funny and sensational enough to post about it now
Blinkx Video: Underwater Exercise Bike Cycling - Distance