I find that I'm having a great deal of trouble staying alert 8 hours per day. I've heard of people who've negotiated work contracts of just 4 hours/day, arguing that they won't be able to do much more in eight hours.

I am often overwhelmed with drowsiness, boredom, distraction. Some days, I seem to blaze through eight hours in a furious explosion of productivity; other days, I hardly get anything done at all. Most days, it's somewhere in between, and I feel bad for wasting a lot of time because I can't muster the concentration to be my best throughout much of the day.

I'd like to hear your experiences (tell me I'm not alone!), and, if found, your solutions to this dilemma.

Are you productive 8 hours/day almost every day? How?