Internal energy is tricky.
On the one hand, energy is more reliable than happiness. I liked this reflection by Jocko Willink in the Huberman podacast. Everyone experiences joy and sadness as part of their daily lives: keeping a certain energy level is more feasible than a certain level of happiness.
On the other hand, as with anything related to habits, it's way easier to preach than practice. Many years ago, someone I love dearly told me that he tried to do more of what he liked and less of what he didn't. I remember thinking, "Doh, what a naive approach to life". Now I think there is deep wisdom there. Your internal energy is the result of a balance. You can have more money by either making more or spending less; you need to pay attention to both.
In my case, I know pretty well what energizes me. Spending time with my beloved ones, exercising, learning and building things, reading, or walking on the beach are simple activities that raise my energy levels. Except for building things, which I'm lucky to do for a living, I haven't had nearly enough of the others in the last months. As I said, easier said than done.
I recently learned in Emotional contagion that introverts are way more likely to be affected by others' emotions than extroverts.
…One important implication of this constitutional difference is that introverts are easier to condition than extraverts… Extraverts should also be better to resit other’s emotions.
As a hard-core introvert myself, this bit resonated. Good to be mindful about the impact of interacting with negative content — or negative people — on your energy levels. Those can drain your energy without you even noticing they are the culprit.
Finally, there is the internal engaging component. When you experience something that triggers you, how do you react internally? I've naturally sucked at this. Even if it is rare for me to publicly engage with things I disagree with, I tend to ruminate over them, which can be really energy-draining. Yes, someone is wrong on the Internet and all that. Letting things go and saving the fire for that one percent of worthy internal battles is a superpower regarding your energy levels.