Effects of Sauna Alone Versus Postexercise Sauna Baths on Short-term Heart Rate Variability in Patients With Untreated Hypertension
Bibliographic record
Abstract
In Brief PURPOSE: We measured the effects of sauna bathing alone or a 30-minute exercise session followed by sauna bathing on short-term heart rate variability (HRV) in subjects with untreated hypertension. METHODS: Ten patients with untreated hypertension (age 59 ± 10 years) were randomly assigned to (1) a control resting session, (2) two 8-minute sauna-only sessions (S), or (3) a 30-minute aerobic exercise session at 75% of maximal heart rate followed by a sauna session (ES). Spectral analysis of HRV was measured with a Polar S810 heart rate monitor at baseline, during the sauna session, and 15 and 120 minutes after the sauna session (T15 and T120). A Fast Fourier Transformation was used to quantify the power spectral density of the low-frequency (LF) and high-frequency (HF) bands. RESULTS: For S and ES conditions, LF (NU, normalized unit) and LF/HF were significantly higher (P < .05 and P < .01) in the first and second sauna sessions, and HF (NU) was significantly lower (P < .05, first sauna). At baseline and T15 for S and ES versus control, LF (NU) and LF/HF were significantly higher (P < .05), and HF (NU) was significantly lower (P < .05), without any effect of the 30-minute exercise session. CONCLUSIONS: A single sauna session induced a significant alteration of autonomic cardiovascular control in patients with untreated hypertension, with an increased sympathetic and decreased parasympathetic drive. These alterations were normalized within 15 to 120 minutes after sauna bathing. Additional studies are required to document long-term effects of chronic sauna bathing on autonomic control in patients with hypertension. The effects of sauna bathing alone or an exercise session followed by sauna bathing on heart rate variability spectral parameters (high and low frequencies) were measured in 10 patients with untreated hypertension. An increased sympathetic and decreased parasympathetic drive occurred during sauna bathing, with normalization 15 to 120 minutes after sauna bathing.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".