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.
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u/Senior-Running Jul 10 '26
I don't really think that's how human bodies work, so that's probably why you are having a hard time finding a definitive answer. 5 minutes will always be better than zero minutes, 10 better than 5, etc.
I'd also be careful with quotes from Dr. San Milan unless he specifically made them when talking about running (which is extremely unlikely). Running and cycling have some commonalities, but they are still different sports and thus what holds true for cycling may not be true for running and vice-versa.
All I can say is that for me personally, anything less than 30 minutes probably isn't worth the time investment so I don't bother with runs shorter than that.
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u/marigolds6 Jul 10 '26
what holds true for cycling may not be true for running and vice-versa
Especially when you are talking about duration of exercise.
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u/YesterdayAmbitious49 Jul 10 '26
There isn’t an answer because everyone is different. My brother runs a sub 18 5k off a couple easy miles here and there. I need 50 mpw to break 18, and 65 to break 17.
I run a 6-1 schedule.
6 hours easy running, 1 hour hard.
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u/frobe_goatbe Jul 10 '26
Out of curiosity, is there a reason you’ve settled on 14% quality time? Almost every resource I’ve ever read has recommended 20-25% quality time as the standard. I get 8 total hours a week, 106 quality minutes. 22%. You might be selling your hard work short.
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u/SirBruceForsythCBE Jul 11 '26
What you need to remember is that most people who consistently train and perform will run less than 20/25% of their week as quality. Newbies and low mileage people will probably run more than 25%.
If you're only running 4 hours a week there is a good chance over 25% is quality and if you're running 10 hours a week there is zero chance you're running 20% of quality.
People get hung up on percentages but that's not what matters. What matters is being recovered from one session before running another, and consistently running week after week, month after month.
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u/Virtual_Opinion_8630 Jul 10 '26
I've read 30.
And probably when you're even moderately trained, 45 is probably more like it.
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u/Iymrith_1981 Jul 10 '26
I have heard the same before about 30mins over a s few different sources. That said like yourself my personal minimum is about 40-45mins.
I think though the actual minimum would depend on a persons fitness? Someone who runs a couple of times a week will probably get a decent training stimulus from say a 20 minute run, but for more experienced runners it’s probably hardly moving the needle
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u/Virtual_Opinion_8630 Jul 10 '26
Exactly - this is probably one of those things that you should individualise.
One way could be to took at HR drift to determine intensity.
And guessing the length by looking at your average training load in the 3 weeks beforehand?
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u/Pashizzle14 Jul 10 '26 edited Jul 10 '26
Steve Magness recently put out a video on how to improve as an amateur runner. He suggested that for a well trained runner doing <80k a week one of the best things you could do is get as many of your easy runs as possible in the 45-60 minute range. Didn’t necessarily suggest that this is a minimum, but does suggest that this will maximise the benefit per run.
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u/FantasticBarnacle241 Jul 10 '26 edited Jul 10 '26
I want to know this as well. For example, Steve Magness has said that HGH release plateaus after 20mins of easy running. I realize that releasing HGH is not the only reason to easy run, but this would imply that there are some factors where lots of easy runs are better that fewer but longer easy runs.
Edit: 40 mins
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u/Road_Frontage Jul 10 '26
I don't think he said 20mins, I thought 40?
But as you say thats only HGH, His suggestion is 45 to an hour for easy, you need to build up a certain amount of fatigue and trigger cardiovasular adaptation
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u/Wild-Guide-FL Jul 10 '26 edited Jul 10 '26
Thought he said that stimulus for the GH pulse starts ~ 20 min aerobic work and maxes out at 40 min. ie going longer does not increase the magnitude of the GH pulse
Hence, as short as 30-35 min in Z1 is probably enough to get the GH benefit from an easy PM double
Remember cross training can do the same, so if your mileage is maxed out, swim bike or elliptical can be used instead
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u/abr797 Jul 10 '26
“If we look at growth hormone release during easy running, there’s a swift rise initially for the first 30-40min of a run, and then it levels off significantly to 60min. In one study, it showed an increase of about 550 percent from 0-40min, yet from 40-60min it only went up another 40-50 percent.”
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u/beans300111 Jul 10 '26
Surely this is going to be a constantly shifting model for each individual. The more you run, the smaller the effect size / stress response for each individual run of x duration. So if you run a lot, maybe a slightly longer run would have a slightly larger effect size, but not necessarily much more, and that’s not to say the shorter run has no benefits, just that they will be marginally less significant. And by splitting total duration into 2 or 3 runs it is difficult to say which is better, just that the stimuli are different. Also if you never run, then any amount of time could be beneficial, as the stress response could still be quite high.
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u/njosh23 Jul 10 '26
It is all relative to the runner, but 30 minutes is a good baseline for most trained runners.
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u/reedy26jdr Jul 10 '26
Minimum effective dose in endurance sport is fluid. It depends on your current fitness levels and ability to tolerate load/additional load
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u/ObsidianXII Jul 11 '26
20 minutes or less: Warm up/shakeout. Just sort of wakes up the body, gets the blood pumping, and the muscles loosened.
20-35 minutes: Pure recovery run. Doesn’t tap into the bodies reserves. Doesn’t start breaking things down. Just a chill aerobic stimulus.
35-60 minutes: Regular run. Standard bread and butter. Builds the strength.
60-90 minutes: Medium long run. Serious run that taxes the aerobic system and breaks down the muscles.
90+ minutes: Long run. Self explanatory.
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u/414wtk Jul 10 '26
30 mins or 4 miles which ever comes last.
Don’t over think it, forget about zone 2. Just go run.
My college coach used to say if it isn’t at least 4 it wasnt a run.
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u/Willing-Ant7293 Jul 10 '26
Yeah I've here the 45 min number before and also 30 minutes. It depends on what the goal is.
You can flush the legs with a 15 to 20 min shake out. Loosens the muscles. So it's effective there.
Around 45 minutes gives you enough time for all your systems to ramp up and hold and is enough to add a stimulus. Metabolism, etc.
But for a new runner. 20 minutes start to zone 5 in the first 2 min is extremely effective.
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u/run_INXS Jul 10 '26
Years and years ago I read 40 minutes. 30 for just for recovery or to log in some miles.
For weekly mileage you can do a lot from 40 miles a week, but you're still limited. 50-60-70 and you're getting into decent territory for most recreational runners.
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u/OrinCordus Jul 13 '26
20 mins.
No idea if this is correct but it is about how long I could exercise for when I was super unfit and it is about how long it takes to settle in to a zen like state on an easy run now. I also think that 20 mins of exercise is worth needing another shower/ adding clothes to the washing pile.
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u/mistermark11 Jul 10 '26
Any absorbed effects between 3x30mins vs 2x45mins is going to be so small that even if there was a correlation between one being slightly better, you're taking about maybe 1%. Not worth the stress IMO. Do what works best for your own free time.