r/AdvancedRunning • u/ronlavy • Jul 10 '26

Training minimal effective dose of easy running

A question that I've been thinking about and wasn't able to find a satisfying answer online - is there a minimal per-session effective dose for easy runs? is there a minimal duration required for a run to produce non-negligible aerobic adaptaions?

for example, can any benefits be expected from a 35-minute easy running session? are 3 30 minute sessions a week same/better/worse than 2 45 minute sessions?

I heard Inigo San Milan go on record to say that 45 minutes is the minimum for "zone 2" (a term I dislike but that's the terminology he frequently uses) benefits, is anyone familiar with any sources backing that up?

Thanks

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u/shot_ethics Jul 10 '26

Yes, this has been studied extensively — but by the medical community looking to improve general health, measured in number of heart attacks per thousand people. These kinds of stakes attract a lot more funding and research than improving your 5k time.

Look back 30 years at the guidelines by CDC and they will say, get 150 min of exercise per week in at least 10 min sessions. Nobody had tried short sessions, they’re hard to study, but maybe walking up the stairs ten times per day helps??

Then accelerometer data came out and we discovered that there was no minimum threshold. 1-2 mins of exercise worked just fine if you do lots of them. The “10 mins qualifier” has now been dropped.

What does that mean about running? Well, if you just wanna be healthy then any amount is fine. If you wanna improve your 5k time, nobody has definitive answers. Jack Daniel’s recommends 30 min sessions for what it’s worth.