Aerobic vs. anaerobic work in everyday life

We're just finishing up finals week, and for some reason December finals week always seems rougher than the one in May. (Maybe because we're not on the doorstep of paradise, I mean summer vacation).

Last week I took a how-to class for using a heart monitor while spinning (riding a type of stationary bicycle). It emphasized the importance of staying within the aerobic range of heart rate, and, if we get into anaerobic, do it only for a limited time followed by time in a recovery range.

As I understand it (and it's a limited, and probably inaccurate understanding), exercise in the aerobic range is both more healthy and more sustainable. The instructor told the story of bicycling outside with a friend. The friend flies up hills, going into anaerobic work, while the instructor goes more slowly, staying aerobic. It takes the instructor longer to get to the top, but once he does he takes off on the level ground while his friend is still trying to recover.

I wonder if a similar dynamic exists with the energy we put into our every day life and work. For most of November, I focused on working moderately hard each day, and going home while I still had energy to work. (Think: staying below 85% of maximum heart rate). I often felt I could have gotten more done in any given day, but I was surprised at how much I did get done each on an on-going basis; i.e., each day was productive.

In finals week, however, I have been pushing as hard as I can each day, which coupled with increased family obligations, has left me exhausted. The first several days of this I was pleased at how much I got done, essentially burning up reserves, but the last couple days have been much less productive because I've been exhausted. By analogy, I pushed into anaerobic work, and it wasn't such a good idea.

Thinking back on the week, I actually didn't need to push so hard and could have stayed in the steady, moderate-effort pace of the prior weeks. I could have done this by taking a little longer to get grades back + putting aside some other, ongoing projects in recognition of the extra work required by finals week.

(BTW, in writing this, I managed to spell "anaerobic" three different ways and each looked correct. :-(