You can run a 5k like it’s no biggie and crush your spin class on the reg. But as soon as you climb a couple of flights of stairs you’re well on the way to winded. Sound familiar?
The good news is, you’re not out of shape (and you’re not alone.)
Turns out, there’s a perfectly reasonable explanation for why it’s such a workout. And it’s all down to which energy system we’re using.
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According to Metro, our bodies run on Adenosine triphosphate (aka, ATP) – the petrol that keeps us alive and functioning. But how much of this we produce is determined on which energy system we use to do so.
When we exercise, we automatically switch between different sources of energy – long, slow exercises (like marathons) use the aerobic system, burning through carbs and fat. The slightly faster-paced stuff (such as a 400m run, for example) relies on the lactic system, which produces ATP without oxygen and is manufactured from the breakdown of glucose to pyruvic acid in the muscles.
Lastly, for sprints or explosive movements that need short bursts of energy, we use the phosphocreatine system – the most quickly expendable source of ATP. This is what we tap into when we climb stairs, but it only lasts for 10 seconds or so and comes from the glycogen already in our cells. After this, we move on to the next energy system and after a while – into the aerobic one (which is the most sustainable and least painful source of fuel.)
This explains why the longer the flight of stairs, the easier the workout becomes.
Celebrity fitness trainer Scott Laidler believes our training regimes don't help.
“Whilst we typically use stairs every day, our actual fitness pursuits are not centred around stair climbing,” he tells the publication.
“No matter how fit you are unless you explicitly train to get better at climbing stairs the chances are that they’ll always pose a bit of a challenge.”
Plus, when it all boils down to it, the activity is extremely tough.
“You are often going from rest to a state of elevated heart rate, whilst propelling your entire bodyweight on one leg, against gravity with each subsequent step adding to the challenge,” Scott added.
Yup, when you look at it that way, it’s no wonder stairs suck so much!