I was diagnosed with “hyper activity disorder” as a wee little kid, and if you go by what people who have known me my whole life say, I’ve always been a high energy person compared to others. It’s only becoming obvious to me that it’s true now that I’m in my mid-30s and there are people younger than me who complain that they can’t keep up. Thinking about that has led me to wonder something related…
Why don’t people who are about the same age, are the same gender, are similarly healthy/unhealthy, have similar diets and similar height-weight ratios have the same amount of energy? It varies a lot even among those who seem to be in the same shape, not just between those who are fit and those who are in ill health.
What goes on biologically to cause some of us to easily race around all day after eating 2000 calories/day, and someone else to be fatigued if they tried the same thing? Are energetic people better at converting food into fuel for activities? Or is the difference more psychological rather than physiological, and others have the potential for the same activity level but their more normal brain chemistry saves them from it? (and here I veer off into thinking about zombies and disinhibition…)
The answer is complicated. Let me see here. There is chemical energy in food. There is mechanical energy spent on eating food. There is some chemical energy-to-mechanical energy conversion going on. There is some potential energy to store energy in molecular bonds – energy that once came from the chemical energy in food. There is the metabolic rate, the rate at which chemical reactions within a body occur and produce ATP molecules for muscle cells. Often, there is a variation of a species. You may also want to take into account of family history, because family history is your history. When you take all these things into account, the answer should be very complicated, I presume.
This is a qualified guess but I don’t think energetic people are better at converting food into fuel for activities. I suspect it’s rather a combination of two interacting factors. Energetic people have a different psychology causing a higher activity level, and having a higher activity level has a physiological effect improving the body’s stamina, which means they not only want to or are driven to more activity, but are able to maintain that level whereas someone sedate just couldn’t.
Energetic people probably expend more calories than non-energetic people and either have to consume more calories or lose/maintain weight compared to a non-energetic person.