My non-vehicle-owning roommate finally broke down and rode a bike with me to work. After his brutally hot and long public transit experiences this month, he conceded to a 20 minute bike ride instead.
I gave him some riding pointers, but he insisted that HIS methods of riding and energy conservation were superior and that 'he just doesn't ride like that'. I kept a slow & steady pace, but he was wobbling around, sweaty & out of breath at about mile 4. He did make it though. Finally, he confessed that it must have been the BIKE that caused his mid-ride malaise.