What is Athlete Mode? Ten fitness metrics beside your doses

Athlete Mode is new in 1.4.0: a sixth tab that draws the fitness readings a watch writes to Apple Health beside the doses logged in Peptrend. Health holds the readings and knows nothing about the doses. Peptrend holds the doses and, on its own, none of the readings. The tab is the join.

What is Athlete Mode?

Athlete Mode is the weight chart’s premise applied to recovery and fitness numbers. That premise, there since the first version of the app, is that a noisy daily series has a trend underneath it, and that the trend only shows once the series is charted properly; bodyweight is a time series makes that argument for the scale. A watch produces the same kind of series about your heart, your lungs and your sleep, and anyone logging doses in Peptrend already holds the other half of the picture: a record of what was taken, how much, and when. Athlete Mode gives each metric its own chart, smoothed and coloured by your dose history.

It is opt-in. Onboarding offers it once, at the end, and the same switch lives in Settings › Athlete Mode from then on. With the mode off, the tab is absent from the tab bar entirely, and the ten Apple Health read permissions are never requested. Someone who leaves it off is never shown a permission sheet naming heart rate variability or blood oxygen; those types are asked for at the moment the mode is turned on, and at no other time.

What does it read, and what does that need?

Ten metrics, all read from Apple Health: VO₂ Max, Heart Rate Variability, Resting Heart Rate, Cardio Recovery, Walking Heart Rate, Respiratory Rate, Blood Oxygen, Sleeping Wrist Temperature, Exercise Minutes and Active Energy. Heart Rate Variability is the SDNN measure, read from HealthKit’s heartRateVariabilitySDNN type. Cardio Recovery and Respiratory Rate start hidden; every metric can be shown, hidden and reordered in Settings.

The tab needs a wearable writing those types into Health, because it reads Health and nothing else. With no device recording them, there is nothing to draw. Peptrend takes the readings exactly as Health serves them: a day with no reading produces no point on the chart, never a zero, which matters for a metric like VO₂ Max that updates every week or two, and a metric your device has never recorded shows an empty chart while the rest of the tab carries on.

Everything here is read-only. Athlete Mode adds ten read types and writes nothing; body mass remains the only thing Peptrend has ever written to Health. The weigh-in side of the Health connection is older and separate, and importing your weight history from Apple Health covers it in full.

How does the dose colouring work?

Each chart’s line takes its colour from your dose history. The colouring has two modes: by the dose in effect that day, or by the estimated amount still circulating. Both use your shot colour scheme from the dose charts, so a shade means the same thing here as it does there. The tint can sit on the smoothed line, on the raw readings, or on both; smoothed is the default.

The circulating figure is the one the Doses tab already draws: an estimate of the milligrams remaining from each logged dose, decayed by a published half-life. How that estimate reaches a steady state and how a single dose is absorbed and cleared each have a post of their own. Coloured this way, a titration step becomes visible in the fitness charts the same way it is in the weight chart: the line changes shade where the dose changed, and whatever the metric did around that point sits in plain view, in its own colour, over its own dates. What that co-occurrence means is a question the app deliberately leaves open.

Which trend methods smooth these charts?

The same ones that smooth the weight chart, picked from the same swipeable strip. The strip stays pinned at the top of the tab, the header folds into a one-line summary as you scroll, and changing method morphs each line into its new shape rather than redrawing it from scratch. That morph is new in 1.4.0 too, and it applies to the Trend tab and to every Athlete chart alike.

1.4.0 also changes what a fresh install sees. The strip starts with three methods, Rolling Median, Robust Adaptive EWMA and Weekly Average; the rest of the fifteen are a tap away in Settings, and the advanced list is Pro. Anyone who already picked a set keeps it, and all fifteen methods still exist; the three are only the starting selection.

One time frame governs the whole tab, and it defaults to your goal period, so every metric is drawn over the same span the goal chart covers. Loading starts at app launch, ahead of the tab being opened, and a refresh control forces a fresh read from Health whenever you want one.

What do the baseline, split averages and correlation add?

A pre-dose reference, a two-sided average, and a rank correlation, each summarising the chart it sits on. All three are off by default and switched on in Settings. The baseline is computed from the weeks before your first logged dose, so the pre-dose level of a metric stays visible under everything that follows. The split averages divide the readings at a threshold computed from your own data, recomputed as that data changes, and show the average on each side of it. Both are plain lines and numbers on the chart.

The correlation is a Spearman rank coefficient between each metric and the same-day circulating amount. Spearman’s version correlates ranks rather than raw values, so it asks only whether two series tended to move together, without assuming the relationship is a straight line. Switched on in Settings, the correlation appears once fourteen or more days carry both a reading and a dose estimate, never below that, and never without its caption, which the app states verbatim: “Describes what happened together, not what caused what.”

That caption is the load the feature is built to bear, so it is worth spelling out. The pairing is same-day only, which means the coefficient carries no claim about delay or build-up. The label beside it, from “no clear relationship” to “a strong relationship”, grades the size of the coefficient and nothing else. And a run of days from one person is not a study: there is no control group, and sleep, alcohol, illness, travel and training load move these readings as much as anything else does. A correlation here is a description of one past, not a verdict on a medication.

What does Athlete Mode refuse to say?

Whether a reading is good, which way it should move, or what caused it. Every metric carries a short explainer of what the reading measures, and the explainer stops there. There is no score, no grade, no colour-coded verdict, and no sentence anywhere in the tab that promises a dose will move a number. The app records what you enter, reads what Health holds, and does arithmetic on the two.

That restraint is deliberate, and it runs through the rest of the app: the reconstitution screen refuses to compute a draw volume on the same reasoning, that a number the app cannot stand behind is a number it should not print. Two series moving together is a fact about one person’s past, and the tab is built to say nothing beyond it. What caused what, and what to do next, are questions for you and whoever advises you on your protocol.

What does it cost, and where does the data live?

Athlete Mode is part of Peptrend Pro, and its data stays on your devices. The tab appears once the mode is on, and on the free tier the metric charts sit behind the same gate as every other Pro surface; what stays free lists both sides of that line, along with the prices. Turning the mode off removes the tab entirely, on either tier.

Three of the ten metrics get a post of their own, because each carries a measurement problem the chart cannot solve for you: VO₂ max has your body mass in its units, resting heart rate is the one metric with randomised evidence behind it, and active energy counts the cost of moving a body that is getting lighter.

The data path is the same as the rest of the app. The ten types are read on the device, charted on the device, and synced through your own private iCloud database; no server of the app’s own is involved, and the privacy policy is short enough to check that claim against. Body mass is still the only type Peptrend writes to Health, the ten fitness types are requested only when the mode is turned on, and switching the mode off takes the tab out of the app until you want it back.