How does that compare with your usual schedule? If it's substantially more than usual, I'd expect you to be tired. Keep it up for a few weeks, and you'd be surprised how well your body adapts to it.

I ride 35 miles or so almost every day. And since I do it every day, it's no big deal at all. But give me 3 weeks off the bike, and all that changes. Suddenly, that 35 miles a day is exhausting.

I had that happen a couple of months ago. I didn't ride nearly as much because of work, vacations, and the like. And getting back into the routine, I found myself more tired than usual. Enough so, that I mentioned an epiphany to my wife.

"I'm exhausted. You know, 35 miles is a long way to ride every day."

Her response was predictable.

"You're just figuring that out?"