Your brain is hard-wired to avoid exercise. Here's why

We all know that working out makes us feel better. So why is it so hard?

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Published: January 20, 2024 at 9:00 am

Humans aren’t the fastest or strongest species. We’ve no wings, fangs, claws, venom, or armour. Physically, we’re largely nature’s also-rans.

‘Also-ran’ is an ironic term, though, because humans do physically dominate all other species in one area: long-distance running. Our bipedal gait and unique sweat glands mean humans can keep running long after other species collapse from exhaustion.

Humans evolved to spend long periods physically exerting themselves, that is, exercising. But while many people do indeed enjoy exercising, they’re in the minority (as the less-crowded gyms and abandoned New Year’s resolutions of mid-February reveal).

So why, even though we’ve evolved to do it, doesn't everyone enjoy exercise? The baffling complexity of the human brain is to blame. Evolving an ability doesn’t automatically mean we’ll want to use it. Creatures with armour don’t actively want to be attacked.

While physical exercise isn’t that bad, it’s still typically unpleasant, and uncomfortable. It has to be; you’re pushing your body to its physical limits, which leads to significant discomfort – they’re limits for a reason.



How your brain thinks about exercise

Another issue is that the human brain is highly sensitive to wasted effort. Studies have shown that they contain dedicated circuits, within the insula cortex, that calculate the effort required for actions – they're there to ask "Is it worth it?"

It’s an evolved tendency to stop us from squandering vital resources on pointless endeavours, like walking 20 miles for a handful of berries.

But regular exercise to get 'in shape’ requires constant and considerable effort – all for gradual progress and uncertain rewards (it’s impossible to guarantee ahead of time that you’ll succeed). So, your brain’s tendency to ask, "Is it worth it?" will be hard to quieten.  

This trait also means we typically prefer things which offer minimum effort for maximum reward. So we take the path of least resistance, stick to routines and dwell within our comfort zones.

Taking up exercise means changing all that, for uncertain results. To keep us safe, our brains typically tend to put more significance on risks rather than rewards, meaning we are even more reluctant to take up physically demanding activities.

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So, while our bodies may be adapted to constant exercise, our brains have in many ways adapted to avoid it. And we’ve built a world for ourselves where avoiding physical activity is a viable option.

Thankfully, the human brain is a terrifyingly complex organ, so has a few tricks up its metaphorical sleeve. Most obviously, it isn’t ruled by its more primitive, immediate instincts and drives. While many species’ thought processes are limited to ‘Food, eat it!’, ‘Danger, run!’, ‘Pain, avoid!’, we’ve evolved beyond that.

Human brains can form multiple long-term goals and ambitions. We’re rarely content with just day-to-day survival: we can simulate a desirable future scenario, figure out how we’d achieve it, and… do just that. Or at least work toward it.

This directly impacts how our brain processes motivation and willpower, in many interesting ways. For one, it makes us capable of delayed gratification: we can recognise that rejecting a reward now can lead to a greater reward later, and act accordingly.

In this case, we understand that eating four family bags of crisps while bingeing TV will be enjoyable at the moment, but going to the gym will mean we’re fitter, stronger, and healthier later.

And then there's the ‘just world’ fallacy. This is where we assume the world is fair, which leads us to believe – and studies have shown this – that any suffering will surely lead to rewards later. No pain, no gain, as the saying goes.

How your brain gets motivated

So how does the brain process all these different motivations? The self-discrepancy theory suggests we have several ‘selves’ active in our minds at any given time; our ‘actual’ self, our ‘ideal’ self, and our ‘ought’ self.

Your ‘actual’ self is your current state, how you are right now. Your ‘ideal’ self is what you want to be. And your 'ought' self is the self that does all the stuff required to become your 'ideal' self. It’s the self that does what you ought to be doing. So, if your 'ideal' self is a professional footballer, and your 'actual' self isn’t, your 'ought' self is the one that spends a lot of time training, exercising, and getting better at football.

That’s just one framework for how motivation works when it comes to physical exercise. There are, of course, many other factors that play an important role, like time constraints, body image and mobility.

But as far as your brain is concerned, there are processes that discourage exercise, and processes that encourage it. Ideally, you’ll end up putting more weight on the latter than the former. And moving weights around is a go-to type of exercise, so it helps to start somewhere.

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