Regular Sauna Use to Lower Blood Pressure in Primary Aldosteronism

Sauna as an Adjunct to Usual Medical Therapy for Non-reNAl Sodium Elimination in Primary Aldosteronism: Pilot Study (SAUNA-PA)

1. Background and Rationale: Primary aldosteronism is a hypertension-related disorder where salt restriction/salt loss is a central part of therapy. Dietary salt restriction to sufficient degree is very difficult for most patients and thus medications are frequently required to control blood pressure. Non-pharmacologic means of reducing total body sodium and blood pressure are required and desired by patients. Sauna bathing is a traditional wellness practice associated with extensive sweating and therefore salt loss. We wish to study whether incorporation of sauna bathing into a treatment plan for primary aldosteronism might lower blood pressure without increased medications. A pilot feasibility study is required prior to design of a larger controlled clinical trial. We are looking to conduct a short term simulated sauna study to assess patient acceptability and study feasibility as the primary outcomes.
2. Research Questions and Objectives: This study will test the feasibility of having patients add regular sauna usage to their weekly lifestyle, while being treated for hypertension due to primary aldosteronism. The primary objective will be to assess patient recruitment rates, subject retention, patient acceptability, and patient adherence to regular sauna intervention during a 2-week period, using an a priori "traffic light" decision matrix. The secondary objectives will be to explore change in blood pressure, as measured by a wearable, continuous BP wrist monitor, before and after a 2 week sauna intervention.
3. Methods: The study will occur in the context of routine ongoing care in the Endocrine Hypertension Clinic. Ten patients with primary aldosteronism will be recruited to a 7 week study where we will observe the feasibility and acceptability of wearing a continuous, cuffless, wrist BP monitoring device for 2-week periods prior to, during, and after a 2 week "sauna" therapy program. The sauna therapy will consist of three 30 minute visits to a commercially licensed and insured local sauna club each week for 2 weeks. Standardized subject experience questionnaires will collect feasibility and acceptability data which will be analyzed with a standard red light/yellow light/green light approach to study feasibility conclusions.

Inclusion Criteria:

• a) Age 18-65 b) Hypertension with PA diagnosed using Endocrine Society's 2025 criteria c) Stable medical therapy with no change in dose/agent in prior 6 weeks d) BP uncontrolled, clinic > 140/90 or ABPM mean > 135/85 e) Dietary sodium moderate or higher (> 128 mmol/d) f) Subject owns iPhone (12-16) or Android and willing to install HiLo app

Exclusion Criteria:

1. BP > 160/105 in clinic or > 155/100 on ABPM
2. Planning adrenalectomy or other surgery during trial
3. Recent hospitalization for any reason, in the past 3 months
4. Confirmed or suspected MI, angina, CHF or arrhythmia diagnosis in the past 6 months
5. CKD, eGFR < 30 ml/min/m2
6. Pregnancy, planned pregnancy, or non-use of contraceptive during study
7. Recent hypotensive event/syncope in the past 3 months
8. Any complex medical condition where sauna exposure is not advised
9. Planning major dietary change
10. History of medication non-adherence
11. Night shift worker / at work after 2000h
12. Planned vacation/absence during 6-week study
13. Inability to read English or consent to participation