I've noticed that the more meetings I have in a day, the more exhausted I am at the end of it. I am far less tired by a day filled with coding. I don't believe that I am so old that the activity of walking between meeting rooms in the same building 5-6 times per day is sufficient cause to create the difference in energy levels.
After a day of coding, I feel (assuming things worked!) energized and as if my brain is well-worked. After a day of meetings, I feel anxious, restless, and exhausted. When I see a day that is "all blue" on my calendar, it is much harder to get psyched about getting to work. Ten hours of coding is easier for me to do than five hours of meetings.
One manager suggested that this was because of my INFP personality type... That meetings are hard work for introverted people. I think that's a large part of it. Another component is that I crave coding... I am hooked on the joy of making something work!
As I look to the next week, it has a better balance (so far) than last... I have a list a mile long of things I want to code. And a shorter list I have to code... This INFP will have to find the discipline to do the things on the shorter list first! With just a few things mixed in from my longer list....