Effects of Kneipp Hydrotherapy in Post-COVID-19 Patients (HydroCoVitalB)

December 1, 2025 updated by: Eggensberger OHG

Effects of Kneipp Hydrotherapy in Post-COVID-19 Patients: A Randomized Controlled Trial

This randomized controlled study evaluates the effects of cold water hydrotherapy in patients with Post-COVID Syndrome. The primary aim is to assess changes in quality of life compared to an usual care setting without hydrotherapy treatment.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Patients recovering from Post-COVID Syndrome often experience persistent fatigue, autonomic dysregulation, microcirculatory disturbances, and low-grade inflammation, all of which may hinder their return to full function. Kneipp hydrotherapy-using cold water applications-can address these pathophysiological changes through several mechanisms:

Autonomic regulation: Cold stimuli trigger parasympathetic activation and improve sympathovagal balance, helping to stabilize heart rate variability and reduce symptoms of dysautonomia often seen in Post-COVID.

Enhanced microcirculation: Repeated vasoconstriction and reactive vasodilation promote endothelial function and tissue perfusion, which may alleviate muscle aches, dizziness, and fatigue by improving oxygen and nutrient delivery.

Anti-inflammatory effects: Hydrothermal stimuli have been shown to modulate cytokine profiles, increasing anti-inflammatory mediators and potentially dampening the persistent, low-grade inflammation implicated in Post-COVID pathophysiology.

Musculoskeletal recovery: Thermo-mechanical stimulation relaxes tense muscle fibers, reduces pain perception, and supports gradual increases in physical capacity, all of which are important for overcoming Post-COVID deconditioning.

Taken together, these effects suggest that adjunctive cold water hydrotherapy could accelerate functional recovery, reduce symptom burden, and enhance quality of life in Post-COVID rehabilitation.

Baseline Assessments:

At baseline, demographic data including sex, age, height, and weight will be collected. Participants will report their current main Post-COVID symptoms, which will be categorized into symptom clusters: Fatigue (A), Cognitive (B), and Somatic (C). Smoking history will be assessed, including smoking status (current, former, or never), number of cigarettes per day, years of smoking, and pack-years.

The time (in months) since the COVID-19 infection that led to Post-COVID syndrome will be documented, along with the number of COVID-19 vaccinations received at the time of infection. Employment status will be recorded, distinguishing between full-time or part-time employment, COVID-related work disability, retirement, unemployment, or disability pension.

Comorbidities will be documented across the following categories: cardiovascular, pulmonary, cerebrovascular, metabolic, musculoskeletal, psychiatric, and other conditions. The severity of the acute COVID-19 illness will be assessed using the WHO Clinical Progression Scale, including information on any hospital admission and length of stay (in days).

Autonomic function testing at baseline (V1) will be evaluated using the Schellong test. Additionally, self-reported work ability and the number of Post-COVID-related sick leave days within the past 12 weeks will be recorded.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
30

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Diagnosis of Post-COVID Syndrome (ICD-10 code: U08.9)
  • Barthel-Index >80
  • Owning a smartphone to receive digital questionnaires and to use the measurement app for heart rate variability
  • Written informed consent

Exclusion Criteria:

  • Existing contraindications for Kneipp hydrotherapy like severe cardiovascular diseases (e.g., decompensated heart failure, unstable angina pectoris, acute myocardial infarction), severe venous diseases (e.g., acute deep vein thrombosis of the leg), severe neurological diseases (e.g., uncontrolled epilepsy)
  • Prior regular practice of Kneipp applications

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
No Intervention: Usual care setting
Usual care setting at home with no hydrotherapy interventions.
Experimental: Post-COVID treatment with hydrotherapy
Cold water hydrotherapy (5-10 minutes each), four times daily during the 3-week program and once daily during the 6- month follow-up period. During the 3-week stay, standard medical care is provided by registered doctors as needed.
Other: Cold water hydrotherapy
Cold water hydrotherapy (5-10 minutes each), four times daily during the 3-week program and once daily during the 6-month follow-up period. Hydrotherapy interventions are individually tailored to each subject based on their responses and include various washing and pouring techniques.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Health-related quality of life by Short Form-12 Health Survey (SF-12)
Time Frame: From baseline (Visit 1) to end of 3-week program (3 weeks, Visit 2)
Change in the Short Form-12 physical and mental component summary scores (minimum score = 0; maximum score = 100; higher scores indicate higher health-related quality of life)
From baseline (Visit 1) to end of 3-week program (3 weeks, Visit 2)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Resting blood pressure (systolic and diastolic)
Time Frame: Daily during first 3 weeks of rehabilitation (Visit 1 to Visit 2)
Change in morning resting systolic and diastolic blood pressure
Daily during first 3 weeks of rehabilitation (Visit 1 to Visit 2)
Post-COVID work-absence days
Time Frame: From baseline (Visit 1) to 3 months (Visit 3) and to 6 months (Visit 4)
Number of days of work absence due to Post-COVID-19 symptoms during the past 12-weeks
From baseline (Visit 1) to 3 months (Visit 3) and to 6 months (Visit 4)
Adverse events recording
Time Frame: From start of intervention (Visit 1) through end of study (Visit 4, 6-month follow-up)
Number and severity of adverse events related to Kneipp hydrotherapy
From start of intervention (Visit 1) through end of study (Visit 4, 6-month follow-up)
Long-term heart rate variability changes (HRV)
Time Frame: From baseline (Visit 1) to 3 months (Visit 3) and to 6 months (Visit 4)
Change in heart rate variability parameters (root mean square of successive differences) measured by photoplethysmography. At follow-up visits patients will measure HRV for 7 consecutive days
From baseline (Visit 1) to 3 months (Visit 3) and to 6 months (Visit 4)
Post-exertional malaise severity
Time Frame: From baseline (Visit 1) to 6-month (Visit 4) follow-up
Change in Post-Exertional Malaise score measured by the DePaul Symptom Questionnaire-Post-Exertional Malaise
From baseline (Visit 1) to 6-month (Visit 4) follow-up
Daily well-being documentation
Time Frame: Daily throughout the intervention and 6 months follow-up phase (Visit 1 to Visit 4)
Self-reported daily well-being recorded via digital diary on a scale from 0 to 100
Daily throughout the intervention and 6 months follow-up phase (Visit 1 to Visit 4)
Autonomic function (heart rate variability by photoplethysmography)
Time Frame: Daily during the 3-week program (Visit 1 to Visit 2)
Change in heart rate variability (root mean square of successive differences) measured by Kyto 2935 via photoplethysmography
Daily during the 3-week program (Visit 1 to Visit 2)
Fatigue severity by Fatigue Severity Scale
Time Frame: From baseline (Visit 1) to end of 3-week program (3 weeks, Visit 2)
Change in Fatigue Severity Scale score (minimum score = 9; maximum score = 63; higher scores indicate greater fatigue severity)
From baseline (Visit 1) to end of 3-week program (3 weeks, Visit 2)
Sleep quality by Pittsburgh Sleep Quality Index
Time Frame: From baseline (Visit 1) to end of 3-week program (3 weeks, Visit 2)
Change in Pittsburgh Sleep Quality Index score (minimum score = 0; maximum score = 21; higher scores indicate poorer sleep quality)
From baseline (Visit 1) to end of 3-week program (3 weeks, Visit 2)
Health status by EuroQol-5 Dimensions-5 Levels
Time Frame: From baseline (Visit 1) to end of 3-week program (3 weeks, Visit 2)
Change in EuroQol-5 Dimensions-5 Levels questionnaire score (score represented by a 5-digit code; each digit represents one dimension, ranging from 1 to 5; higher digits indicate poorer health state)
From baseline (Visit 1) to end of 3-week program (3 weeks, Visit 2)
Long-term quality of life by Short Form-12 Health Survey
Time Frame: From baseline (Visit 1) to 3 months (Visit 3) and to 6 months (Visit 4)
Change in Short Form-12 scores at follow-up (minimum score = 0; maximum score = 100; higher scores indicate higher health-related quality of life)
From baseline (Visit 1) to 3 months (Visit 3) and to 6 months (Visit 4)
Long-term fatigue by Fatigue Severity Scale
Time Frame: From baseline (Visit 1) to 3 months (Visit 3) and to 6 months (Visit 4)
Change in Fatigue Severity Scale score at follow-up (minimum score = 9; maximum score = 63; higher scores indicate greater fatigue severity)
From baseline (Visit 1) to 3 months (Visit 3) and to 6 months (Visit 4)
Adherence to hydrotherapy
Time Frame: During the 3-week intervention phase (up to Visit 2) and over the 6-month follow-up period (to Visit 4)

Proportion of prescribed hydrotherapy applications in the intervention group performed, as recorded in diary or app.

Short-term Adherence: During the 3-week intervention phase, patients are considered "adherent" if they perform atleast one hydrotherapy session per day on at least 75% of study days. The investigators will compare health improvements between high-adherence and low-adherence participants.

Long-term Adherence and Effects: Over the 3- and 6-month follow-up, "adherent" patients are those who continue self administered hydrotherapy at least four times per week on at least 75% of follow-up weeks. The investigators will assess whether these patients sustain greater gains in quality of life.
During the 3-week intervention phase (up to Visit 2) and over the 6-month follow-up period (to Visit 4)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Eggensberger OHG

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Bavarian Health and Food Safety Authority (LGL)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Rembert Koczulla, MD, Schön Klinik Berchtesgadener Land

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 31, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
October 31, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 6, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 6, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 8, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
December 2, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 1, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • HydroCoVitalB

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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