You're 20 minutes away from your one-to-one with your PD/VP.

Your list of topics is enormous: the sponsor pushing back on timelines, the vendor underperforming, the budget that needs defending, three strategic decisions that can't wait. You need to prioritise, you need to think clearly … but you feel exhausted.

It's 4pm. Your brain feels foggy. The decisions seem harder than they should be. That's not a coincidence.

Your prefrontal cortex uses 20% of your body's glucose despite being only 4-5% of your brain's size. By afternoon, you're running on depleted cognitive resources. Every decision you've made since waking has drained your mental battery.

Most PMs and PDs waste their cognitive prime time on emails and routine tasks, then attempt their hardest decisions when their brain is least capable. This post reveals the neuroscience behind decision fatigue and how to identify your personal peak performance window.