Learn covers all three, not just heat The Learn tab now carries cold and hot-water sections alongside the sauna research, each with its own reference list. New explainer: the three stages of cold-water immersion — cold shock, physical incapacitation, then hypothermia. Safety knowledge, not technique. No stage is something to chase, and the app says so. Your session, with the studies attached Cold and hot-water sessions now get the tailored, cited explainers heat has had: what this particular session was, and what the research actually says about it. Plunge after a sauna and you will see the contrast evidence — including its honest gap, since those studies alternated hot water with cold rather than dry heat. A clearer read on consistency Adapt now charts sessions per week against Hormetic's consistency threshold, instead of shading days by minutes logged. Press and hold any weekly dose chart to scrub across it and read the actual numbers, week by week. Delete a session Swipe left on any row in the Log. Useful for the accidental starts that used to be stuck there for good. Accidental sessions no longer count anywhere Tap Start and stop within a few seconds and nothing is recorded — not in Hormetic, and not in Apple Health. Previously a stray tap left a 0:00 workout in Health that Hormetic hid but could not remove. Fixes A hot-tub session followed by a cold plunge was described as a heat session. It now names the soak correctly — hot water and dry heat are kept on separate books everywhere else in the app, and this was the one place that slipped. Every model-derived value is still labeled Estimated, every claim still links to its source, and nothing leaves your device.

SPA MODE — hot tubs and hot baths Step into the water and your Apple Watch Ultra starts the session on its own, reading the water temperature from its built-in sensor. Other models: start it by hand and enter the temperature. • Its own zones and its own estimated soak dose — a separate algorithm from sauna, because a 40 °C soak is not a 90 °C room, and pretending one score fits both would be dishonest • The clock keeps running when you rest an arm on the rim: the rest of you is still in the water. Your Watch taps once and says so on screen • Time immersed is time immersed — the walk to the tub and the towel-off afterward are not counted • Hot-water safety built in: the recommended ceiling, why to stand up slowly, and who should ask a doctor first • Sauna and cold plunge estimates are unchanged

• Cold plunges without a water temperature no longer reach the top zone on time alone — without a reading, there isn't enough to estimate real cold stress. • Sessions over an hour now display correctly on iPhone. • Steadier Watch sessions: sauna and cold now share one session core, so starts, finishes, and Finish & Switch are more reliable. • Estimated sauna scores are unchanged.

Cold plunges, tracked as honestly as your sauna. Hormetic now tracks cold-water immersion alongside heat. Choose Cold on your Apple Watch and it logs your time in the water and an estimated cold dose across three calm zones — Entering, Moderate, Significant. On Apple Watch Ultra it senses when you're submerged and reads the water temperature for you; on other watches, you enter it. Also new: • Cold-water safety, taken seriously — cold immersion carries real risk, and the app covers it with cited sources. • Contrast, explained — follow a sauna with a plunge and Hormetic notes it, with honest, recovery-framed research (never a combined-benefit promise). • Cold trends in Adapt — your weekly cold dose, kept separate from heat. • In cold, heart rate is shown but never scored — cold changes it in ways a wrist reading can't fairly judge. As always, every zone and dose figure is an on-device Estimate. No account, no tracking — nothing leaves your phone.

Steam and infrared sessions now get their own heat-dose estimate. Pick your heat type on a redesigned start screen with bigger, easier-to-tap buttons, and the temperature sets a sensible default for that type (handy in a steam room, where there's rarely a gauge). Also new: • Heat type on every session — your dry / infrared / steam choice now shows on the session screen. • "Before your session" context — see the workout you did beforehand, with honest, research-based framing (never a promise). • A quick "your (10th) heat session this week." • Refreshed science — updated citations and clearer wording: heat adaptations build with how often you go, not any single session. As always, every value is an on-device Estimate. No account, no tracking — nothing leaves your phone.

- Your session keeps tracking accurately even when the Watch screen sleeps — your Zone 3 time now counts for the full session - Left a session running by mistake? Hormetic now notices when your heart rate returns to resting and closes it out for you.

Your practice, summarized. New in the Adapt tab: an on-device summary that reads your recent heat sessions back to you — your weekly consistency and estimated Zone-3 time — and points to the research associated with that pattern. It's generated entirely on your iPhone with Apple Intelligence; nothing leaves your device. Requires Apple Intelligence (iPhone 15 Pro or later, iOS 26+). Also in this update: • Summaries now speak to you directly, in plain language. • Easier to read at any text size, including the largest accessibility settings. • A tidier Log — your week sits pinned up top, your sessions below. Every zone and dose figure is an Estimate, and your data stays on your device.

Hormetic is redesigned around three tabs — and finally shows your habit over time. NEW TABS • Log — your sessions, now with a weekly calendar. Tap any day to open that session. • Adapt — your practice over time: a weekly-consistency streak, a day-by-day heatmap, your estimated weekly heat dose, and your zone mix. Every estimate labeled. • Learn — the research behind the zones, browsable, with every claim linked to its peer-reviewed source. ON APPLE WATCH • A new in-zone pointer shows how far through the current zone you are, at a glance. • Pick your session type — dry, infrared, or steam — before you begin. MORE HONESTY • The session screen now shows exactly what fed each estimate: heart rate (measured), temperature (you entered), duration, and wrist temperature (no live sensor mid-session). • Groundwork for on-device, privacy-first personalization. Still no accounts, no analytics, no telemetry.

NEW — Session summaries, generated on your iPhone • A new "Summarize this session" button on the session detail screen writes a short, plain-language summary of that session, built only from your recorded data and Hormetic's cited research library. • Generated entirely on-device with Apple Intelligence. Nothing leaves your iPhone — no accounts, no analytics, no telemetry, same as always. • Summaries are optional, user-triggered, and labeled Estimated, like every derived value in Hormetic. Related reading links to the same peer-reviewed sources cited throughout the app. • Requires Apple Intelligence (iPhone 15 Pro or later, iOS 26 or later). On other devices the session detail screen works exactly as before. IMPROVED • The Sessions screen now explains where sessions are recorded and adds a one-tap refresh. • Clearer first-run guidance.