Originally Posted by
PatrickGSR94
Some people (like me) can't ride fast all the time, unless it's downhill. And some people (like me) ride in traffic that is ALWAYS faster, no matter how fast you're able to ride, i.e. 35-45 MPH speed limits. And then there's wind that can make it quite difficult to hear approaching traffic behind you. A mirror makes me much more aware of my surroundings than simply focusing on what's ahead.
No one is saying you have to ride fast all the time. The OP was asking how to build up endurance. Poking along at 10 mph is not going to do much for you. Riding as fast as you can will definitely build up endurance.