On one hand, breathing is the safe route that doesn't stop until you're dead, and even at the lower bound average of a random internet search (12 breaths per minute), still provides over $850 a day.
On the other, if walking earned you money, you'd almost certainly become healthier and live longer. Plus, unless you had an accident, you'll be able to put away enough money to live off the interest forever and only a few years of normal walking.
Internet says an average adult breaths 12 - 20 time per minute. Assuming 20 breaths per minute, that comes out to $1,440 dollars per day($0.05 × 20 breaths × 60 minutes × 24 hours)
If you're dedicated, you can walk 20,000 steps in a day. It's not easy, but it's achievable. This would yield $5,000 per day.
For perspective, if you were smart and chose the $5,000 per day, it would take you 547 years to earn your first billion and 131,416 years to have as much money as Jeff Bezos.
Edit: I lost some decimals. I fixed the calculations
I would take steps income. Going for a jog twice per week, assuming I'll be taxed at the same rate as my current job, I'll still earn much more money for way less time investment, plus I would be fit and I enjoy running.
I'd take breath income, purely because it's passive. If you ever lose your legs, you lose your income, but if I ever stop breathing, it's no longer my problem that I have no more income
Given the average amount of breathing that others calculated that would be over half a million of passive income every year. I could live with that as opposed to having to actively find time to walk.
I counted 5 and then 7 steps across 2 breaths. Gotta be at least 50c per step for my to consider it any further. I probably wouldn't accept until $1. And even then, casual cardio like walking would ramp up breathing faster anyway.
Can you walk 24 hours a day though? Your body automatically breathes during sleep, but you need to be awake to walk and not be doing anything that requires you to sit still.
Sleeping, a sit down meal, commuting, office work, even exercise like biking and swimming, all require breathing and not taking steps.
I'd stick to the safe money of breathing. Sure it's less but it's guaranteed, don't have to feel like you're losing money by spending all day on your PC or getting loaded on a beach somewhere. Plus if you get hit by a bus and crippled at least you still have your income.
Except for day’s you’re sick, stuck inside, etc. Then when you get older the walking would be harder but you still gotta breathe. Plus you can still work any job you’d like since people do like to keep busy, and since it’d probably be more of a passion thing you might be hyper-focused and forget to get your walking in for the day. All the stuff I’d be doing wouldn’t have too much walking involved.
I’d take breath, it’s already more money than I could ever spend so why not make it passive?