Sauna Aufguss Ceremony Dataset (N-of-1, 2017–2026): cardiovascular and autonomic responses of a professional sauna master

An N-of-1 dataset of sauna Aufguss ceremonies (nálevy) derived from continuous per-second heart-rate and device-temperature recordings of a professional sauna master (saunamistr) across 2017–2026, extracted from original Garmin FIT files (GDPR export). Each work shift contains several ceremonies spaced ~1 hour apart; each ceremony produces a characteristic heart-rate (and device-temperature) peak. The dataset provides one row per detected ceremony (peak HR, heart-rate recovery HRR60/HRR120, rise rate, width above threshold, temperature delta and lag) and one row per shift (ceremony count, inter-ceremony cadence, coverage, data-quality confidence, summary statistics). Contents: 683 shifts / 2528 ceremonies. Recommended analysis subset is confidence == high (614 shifts / 2278 ceremonies, 2019–2026, continuous 1 s HR); the 2017–2018 era used a sparse-recording device and is flagged low. Key findings: within a shift the cardiovascular/thermal response attenuates ceremony-to-ceremony (the first nálev is the peak event) while short-term recovery is preserved and there is no measurable next-day cost; across years the same heat stimulus produces genuinely lower cardiovascular strain (heat acclimatization), independent of season, despite more work per shift; sauna recovery is not a proxy for aerobic fitness. Includes DATASHEET.md (subject, provenance, detection methods, QC/confidence, full schema, caveats), 20 validation QC plots, and analysis figures + statistics (across-years overlay, mean ceremony shape, per-metric trends, within-shift dynamics, hypothesis tests, deep dives). Caveats: single subject (not population-generalizable); device temperature is the wearable's reading, not a calibrated air-temperature measure; ceremonies are inferred from HR/temperature peaks rather than logged labels; consumer-grade optical/wrist HR. Derived from Garmin-recorded data (Garmin Ltd.).