Anyone who says they love exercise is often treated with suspicion, mainly because finding your get up and go is a struggle for the rest of us.
A new theory based on Harvard biologist Daniel Lieberman's paper - the reassuringly titled 'It is natural and normal to be physically lazy' - has now explained the biological reason why we need to talk ourselves into exercising.
"No hunter-gatherer goes out for a jog, just for the sake of it," writes Lieberman, "They go out to forage, they go out to work, but anything else would be unwise, not to mention maladaptive."
Jonathan Shaw, an editor at Harvard Magazine, expanded on Liberman's idea. "Humans have been selected to exercise only as much as they must to survive," he wrote in a recent issue.
"The ancestors of modern humans lived as hunter-gatherers. In this subsistence lifestyle, food was often scarce, so resting was key to conserving energy for survival and reproduction. In other words, humans were born to run — but as little as possible."
How does Lieberman suggest we combat our natural human laziness? Either, "Make exercise fun by emphasising the social aspect — pickup soccer, running groups, and the like," or by making exercise compulsory in university or workplaces where people feel they don't have enough time.
He adds wisely: "People who get more physical activity have better concentration, their memories are better, they focus better. So the time spent exercising is not time lost, but returned in spades."
You heard the man - get out there.