Yesterday I experienced crippling fatigue from about 1PM until 3:30PM, seemingly out of the blue.
Just that morning, I had experienced a 5-star morning – out of bed before my alarm, two hours of deep work on my goals, energizing 5k run, and dancing to Disney tunes replaying in my head as I got ready for work. Could this be the start of a beautiful, 5-star day?
Then, around 10:30 AM, I started to yawn. What was happening? My morning tea shouldn’t have even begun to wear off. Maybe I was hungry. I just had to hold on another hour until lunch.
I gobbled down half a calzone for lunch and had a Zoom call with a friend. While we caught up on old times, I drank a Coke Zero for a little extra boost to help me through the inevitable ‘rest and digest’ stage I knew would follow lunch.
But then, when our call ended, and I tried to return my attention to work at 1 PM, it was worse than I had imagined. Worse than I have experienced in weeks. It felt like that scene in Star Wars when Obi-Wan Kenobi powers down the Death Star.
I felt that sound in my head. My whole body just shut down. I had been trying not to sit down at work by moving my office chair and using my standing desk. But when this fatigue hit in the afternoon, I crumpled into my chair, lowering my desk in defeat, and barely having the energy to keep working. I hate this feeling. What caused this?
I turned to my energy tracker in Google sheets. Here are the correlations I found:

The most obvious was the fact that I didn’t even get seven hours of sleep last night. I was proud of the fact that I’d gotten up before my alarm went off at 5 AM, but that’s not good when I went to bed after 9 PM.
Second most obvious culprit is that I had accidentally undercut my diet for the last two days. I’m trying to keep my calories around 1700 each day in order to lose weight, but if I go too low, I won’t be able to function well.
Other possible factors: I haven’t been doing my weight training (which seems to have a strangely invigorating effect on me, once I recover) and I’ve been a little low on water. I will keep an eye on those too.
Plan: get plenty of sleep tonight, up my calories, get back on those weights, and drink more water. Being tired is the worst.