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.