Probably three 30 minute runs per week.
How much cardio is ”enough” to reap the health benefits?
The first article I found says:
Running for 20 to 30 minutes, or about a mile-and-a-half to three miles, twice per week would appear to be perfect.
How much cardio is enough to see improvements in your ability to run?
Most articles I find seem to suggest a minimum of 30 minutes, 3 days per week.
If we focus on running specifically, the general consensus amongst experts is that you need to run at least three days per week to improve
Lagging Measures - Results take time: It can take 4 to 6 weeks to notice changes in your aerobic ability and for the actual training effect being felt.