80/20-träning
80/20 training is the idea that most of your endurance training should be done at an easy intensity, with only a small share done genuinely hard. The name is the ratio: roughly four-fifths easy, one-fifth hard.
Almost everyone who says they are doing it gets one of two things wrong.
The first is units. The split is a share of time, measured across a week or a block. It is not a count of sessions, and not something you do inside a single run.
The second is bigger. The "80" only means anything if your easy really is easy, and that depends entirely on where your zone boundary sits. An athlete working from a wrong maximum heart rate can follow the ratio perfectly and still spend the whole week in the middle.
What the approach actually says
Strip the name away and the claim is about distribution. Endurance fitness is built mostly by accumulating a large volume of comfortable aerobic work, and the hard work that develops your top end is effective in much smaller doses. Together those give a week that is mostly easy with a small, deliberate amount of hard — rather than a week of moderate efforts, which is what self-coached athletes tend to drift into.
Two things follow, and the misreadings below all come back to them:
- The easy portion has to be easy enough to leave you fresh for the hard portion. If it takes something out of you, the hard sessions get worse and the structure collapses.
- The hard portion has to be hard enough to be worth its cost, because its job is to stress what the easy work does not touch.
So the ratio is not the point. It is a rule of thumb for producing that separation, and the separation is the point.
The common misreadings
| What people do | Why it does not work | What to do instead |
|---|---|---|
| Count sessions. "Four easy runs and one hard one — about right" | Hard sessions are short and easy runs long, so a session count badly misstates the time split | Add up minutes, not runs. Your log already has the numbers |
| Apply it inside one run. Easy for most of the run, hard at the end, every time | It is a weekly or block-level distribution. Inside every session it leaves you no genuinely easy days — the opposite of the intent | Keep whole sessions easy. Put the hard work in planned sessions |
| Count the whole session as hard. An interval session logged as hard throughout | Warm-up, recoveries and cool-down are easy minutes and belong in the 80. Counting them as hard hides how little hard work you did | Count time in intensity, not session labels |
| Make "hard" moderate. The hard sessions are brisk rather than genuinely hard | Easy that is not easy and hard that is not hard — uniform moderate effort that develops neither end | If you cannot do the hard session properly, the easy days were too hard. Fix those |
| Trust the zone label. "My watch says zone 2, so it is easy" | Your zone boundaries may be wrong, in which case the label is too. This error invalidates everything else on the list | Check what your zones are anchored to before trusting any time-in-zone figure |
| Treat it as a rule. Chasing the exact ratio week by week | It is a guideline, not a prescription. A race week or a taper will not look like it, and should not | Judge a block, and watch which way you are drifting |
The error that breaks the whole thing
Look again at the fifth row. It is the one worth the most to you.
Every time-in-zone figure is built on a zone table, and that table is built on an anchor. If the anchor is wrong, so is every boundary drawn from it — including the one deciding whether a run counts towards your 80. Most watches set zones as a share of a maximum heart rate they never measured, and which anchor your zones use changes where the easy-hard line falls.
The failure in full. Suppose your stored maximum is lower than your real one. Every boundary shifts down with it, so a genuinely easy run reads a zone higher than it is. You respond sensibly by slowing to get back into what the watch calls zone 2 — and now you are too slow to accumulate useful aerobic work. Or the error runs the other way, your easy pace is set too fast, and your "easy" runs sit in the band between your thresholds: too hard to recover from, too easy to drive adaptation. You can hit the ratio to the minute and spend the week in that middle ground.
Which is what 80/20 exists to prevent. The ratio is a defence against accumulating moderate work, and a wrong boundary lets it back in wearing an easy label.
So the order matters. Anchor first, then the boundary, then the ratio. If your zones look suspect, the four reasons your Garmin zones are wrong works through the causes in the order that saves time. The most reliable fix is anchoring them to your lactate threshold rather than an estimated ceiling, because a threshold is a measurable transition and a ceiling is not.
Checking your easy pace without a lab
Two checks that cost nothing and do not need your zone table to be right:
- Can you hold a conversation in full sentences? If you are answering in bursts between breaths, you are above easy, whatever the screen says.
- Could you do the same run again tomorrow? Easy work should be repeatable day after day. If it is not, it was not easy.
Both are cruder than a measured threshold, and both beat a confident number built on a bad anchor. What zone 2 refers to and how to train there cover the feel of easy work in more detail.
One caution: if easy running feels hard for weeks, your resting heart rate has drifted up and your sleep has deteriorated, the problem may not be your zones — the common signs of overtraining describes that pattern. This is not medical advice, and persistent fatigue has causes no training plan can address. If it continues, see a doctor rather than adjusting your ratio.
When the split does not apply neatly
- Low weekly volume. On a few hours a week there is less easy volume to accumulate, and the balance that works tends to differ.
- Race weeks and tapers. These break the pattern deliberately. Judge a block, not a week.
- Terrain and heat. On hills, or where backing off is awkward, time in intensity is harder to control than the ratio implies.
Frequently asked questions
Is 80/20 measured in time or in sessions?
Time. It is the share of your training minutes spent easy versus hard, added up across a week or a block. Counting sessions gives a badly misleading answer, because hard sessions are typically much shorter than easy ones.
Does 80/20 mean every run is mostly easy?
No. It is a distribution across your week, not a structure for a single run. Applying it inside every session leaves you no genuinely easy days, which defeats the purpose — the easy work exists to let the hard work be hard.
Do warm-ups and cool-downs count as easy?
Yes. They are easy minutes and belong in the easy share, which is why logging a whole interval session as "hard" overstates how much hard work you did. Count time at each intensity rather than labelling whole sessions.
What counts as easy in 80/20?
Work below your first physiological threshold — comfortable, conversational, repeatable the next day. The practical problem is that your watch decides this from a zone table, so if the table is anchored to an estimated maximum heart rate the label may not match the physiology.
Does 80/20 work for beginners and low-mileage runners?
Keeping most of your training comfortable holds for everyone, but the specific ratio was described for athletes training a decent volume. On a few hours a week the balance tends to differ, and consistency matters more than any particular number.
Get the boundary right before you count the minutes
A ratio built on a zone boundary you cannot trust tells you nothing about how you actually trained. Lactate Training syncs your Garmin and Strava activities and adapts your plan around zones anchored to your lactate threshold, so "easy" means the same thing in your plan as it does in your physiology.