I’d run for 1 minute, then walk, then run again for 2 minutes, then walk again, and so on and so forth until I was able to run one hour (5 miles) nonstop. I’d set goals
for the day.
For example, I’d say ‘Today, I will run 5 minutes nonstop at least once in a one hour period, then try to run 3 minutes intermittently within that hour for a total of maybe 15 minutes. I’d get so thirsty at first, but then I guess my body got used to running 5 days a week.