On: The world’s oldest ultramarathon runner is racing ...

[swalling]

Perhaps shockingly, African hunter gatherers and sedentary Western office workers have the same daily energy expenditures as far as we know. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3405064/

In other words, people training for ultramarathons really are probably working harder than other people, even accounting for lifestyle and income disparities.