I didn't start having massive fatigue until about 5-6 months after my concussion. I couldn't figure out why, but thanks to a friend who was then seeing the SLP I'm seeing now, I think I did. For the first 4 months or so, I was recovering from whiplash. That kept me from doing a lot of physical activity, including dance, which was a huge social and emotional thing for me. Once I got the OK to start dancing again, I did, a little at a time. I think adding this to working full time and still dealing with the cognitive symptoms of PCS kind of put me over the edge.

The way my SLP explains it is this: Imagine a circle, then divide it in half. Divide one of those halves into 3 parts: Mental Energy, Physical Energy, Emotional Energy. The entire circle represents your daily 'allotment' of brain energy, and the 3 small sections are the amounts of energy a non-brain injured person would use on an average day. The large empty half is surplus energy. If you have a big test, or are running a race, or have a major fight with a partner, you might need to borrow some of that surplus. But usually, there's a lot left over at the end of the day.

Now, imagine another circle. Divide this one into four parts. Label 3 of them as Mental Energy, Physical Energy, and Emotional Energy. That's how much brain energy it takes for a brain-injured person to get through an average day. That remaining one-fourth is all the surplus that's left, and it's a lot easier to not only need that surplus, but to actually use it up. That's where the brain fatigue comes in.

She also told my friend and I that in her experience, the after-effects of one of these heavy days often takes about 48 hours until it really hits. And that was exactly what was happening to me. I'd have a day where something came up, I dealt with it, and felt really good about myself...and then 2 days later, I couldn't get out of bed in the morning. Sadly, it didn't matter if it was "fun" energy (like dancing), either. Too much was too much. And it didn't have anything to do with sleep.