When I hear about renewable energy, my mind goes from wind turbines and solar panels to the pep in my step, or lack thereof. Renewable energy is what I need at four p.m. It’s what I seek instead of a can of Celsius, another cup of coffee, or, if it existed, Lucille Ball’s Vitameatavegamin. It’s the natural, bouncy verve I crave, the kind that comes after eight hours of sleep and a run in the park. Only I don’t sleep anywhere near eight hours, and I don’t run.

A wise man (Scott Galloway) once said, “Young people fake wisdom; old people fake energy.” A wise woman just told me something shocking: people’s vigor starts to wane in their 30s and 40s, long before they’d call themselves old. Buckle up, kids.