What is a threshold in Base?

One number per discipline that every zone, prescription and grade is a percentage of. For running it is the pace you could hold for about an hour, in seconds per mile. For cycling it is functional threshold power, in watts. Run and ride never mix, because they are different capacities in different units.

Do I have to do a threshold test?

No. Base can scan up to three years of your run and ride history and estimate a threshold from your best sustained effort, converting it to an hour-equivalent. It shows you which single effort won, the arithmetic that converted it, and a confidence level — and only then offers to use it.

Why does Base show me the estimate instead of just applying it?

Because every band, prescription and grade in the endurance half of the app is built from that number. A figure that load-bearing being quietly swapped underneath you is exactly the failure the app's show-the-math rule exists to prevent. You see the sessions it looked at, the winning effort, the conversion and the confidence, then you decide.

How often should I update my threshold?

When Base tells you to. It watches for a session that beats what your current threshold says should be possible and raises a prompt, which outranks everything else on the Endurance tab because it changes the numbers every card below is built from. Otherwise, re-scan after a training block.

What if I do not have any history to scan?

Set it by hand. The screen has a stepper and a save action, and a manually set threshold works identically to an estimated one. If you know your recent race paces or have done a twenty-minute test elsewhere, entering it directly is faster and more accurate than waiting for history to accumulate.

Set Your Running or Cycling Threshold in Base

Nothing works before it exists

The Endurance tab gates the prescription half of itself on this. With no threshold set there is nothing honest to prescribe, so it says so and offers to set one up rather than inventing bands.

Cardio fitness, resting heart rate and per-discipline pace trends need no threshold and are shown regardless.

The scan

The thresholds screen. The estimate is presented with its provenance — sessions considered, the winning effort, the conversion arithmetic and a confidence level — and applied only when you accept it.

Estimate from my sessions reads up to three years of history. Three years is past any training that still describes current fitness, so it is effectively "everything".

The scan narrates each phase as it runs — reading, runs, rides — because it is doing genuinely slow work and twenty seconds of silent spinner reads as a hang. It is also the honest presentation: watching where a number came from is what makes an estimate trustworthy.

Runs are cheap, rides are the interesting half

Runs carry distance and duration on the workout itself, so every run in three years is considered without a single extra read.

Rides are harder. A power meter is read straight off the workout's statistics. Without one — which is most bikes — power is modelled per segment from speed and elevation, and the best sustained twenty minutes is taken, which is what a real FTP test measures.

That modelling needs a GPS route, because altitude is where the climbing term comes from. An indoor ride with neither power nor route is counted as unusable rather than being silently averaged into nothing. See estimating cycling power without a meter.

What it shows you before applying

Four things, and this is the part that matters:

Shown	Why it matters
Sessions considered	Tells you whether it had enough to work with
The single winning effort	You can recognise the session and judge it
The conversion arithmetic	An hour-equivalent from a shorter effort is a model, and you see it
Confidence	Modelled power is capped lower than metered power, honestly

A twenty-five minute effort is not an hour effort, and converting one to the other is a documented adjustment rather than an assumption. Seeing the sum is what lets you disagree with it.

Then Use this estimate or Dismiss. Dismissing leaves your current threshold untouched.

Setting it by hand

If you already know the number — recent race paces, a twenty-minute test done elsewhere, a coach's figure — set it directly. A stepper and a save button.

A manually set threshold behaves identically to an estimated one everywhere downstream. There is no penalty for skipping the scan, and it is more accurate than any estimate if your number is current.

The screen also keeps a history of previous thresholds, so a block's worth of progress is visible.

When to update it

Base watches for it. If a session beats what your current threshold says should be possible, a threshold prompt appears at the top of the Endurance tab, above everything else — because it changes the numbers every card below is built from.

Otherwise, re-scan after a training block, or when your easy runs start feeling too easy. A threshold set six months ago prescribes six-month-old sessions.

Common mistakes

Setting it from a hard 5k. A five-kilometre race pace is substantially faster than threshold. The conversion exists for exactly this reason; do not skip it by entering a race pace directly.

Setting it aspirationally. Every band comes from this number. An optimistic threshold makes your easy runs too fast, which is the most common error in endurance training and the one that quietly ruins a block.

Ignoring a threshold prompt. It means the number every prescription is built from is now wrong in a way that has been measured.

Expecting an indoor trainer ride without power to contribute. No power and no route means nothing to model from. It is counted as unusable and said so.

Treating modelled FTP as metered FTP. The confidence is capped for a reason — wind is unknowable from a watch, and a headwind reads as power that was never produced.

Setting run and ride from each other. They are separate capacities and Base keeps them separate deliberately.

What to do next

Run the scan for whichever discipline you have most history in, and read the winning effort before accepting. If you recognise the session and it felt like an honest hour-ish effort, accept it — if it was a race you emptied yourself in, set the threshold by hand slightly lower.