Long COVID SyndromeKOTS-LCNCT07621588
Diaphragmatic Breathing Exercises With KOTS Currents in Patients With Long COVID
A study testing Diaphragmatic Electrostimulation Using KOTS Currents and Diaphragmatic Breathing Exercises in people with Long COVID Syndrome and Post-Acute COVID-19 Syndrome, run by Universidad Pontificia de Salamanca at 1 site in Spain.
Trial summary
This study will evaluate the effects of diaphragmatic breathing exercises combined with diaphragmatic electrostimulation using KOTS currents in patients with Long COVID. Participants will be randomly assigned to one of two groups. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Long COVID Syndrome, Post-Acute COVID-19 Syndrome
- What is being tested?
- Diaphragmatic Electrostimulation Using KOTS Currents and Diaphragmatic Breathing Exercises
- Type of treatment
- Medical device, Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 9 participants
- Where
- 1 siteSpain
- Study dates
- 14 Jun 2026to 7 Aug 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Men and women aged 18 to 65 years.
- Medical diagnosis of Long COVID.
- At least 2 months since SARS-CoV-2 infection.
- Ability and willingness to provide informed consent.
- Ability to participate in the assigned intervention and assessment procedures.
Who cannot join
- Presence of a pacemaker.
- History of epilepsy.
- Pregnancy.
- History of acute cardiac arrest.
- Severe respiratory distress.
- Use of a wheelchair.
Show all 10Show fewer
- Blurred vision.
- Cyanosis.
- Refusal to perform part or all of the treatment.
- Incomplete or incorrectly completed questionnaires.
Trial locations and contacts
1 site in 1 country.
Spain1 site
Clínica Universitaria Salus Infirmorum, Universidad Pontificia de Salamanca
Madrid, Madrid, 28015
About this study
Official title: Effects of Diaphragmatic Breathing Exercises Combined With Diaphragmatic Electrostimulation Using KOTS Currents in Patients With Long COVID: A Pilot Randomized Controlled Trial
This study will evaluate the effects of diaphragmatic breathing exercises combined with diaphragmatic electrostimulation using KOTS currents in patients with Long COVID. Participants will be randomly assigned to one of two groups. The control group will perform diaphragmatic breathing exercises, while the intervention group will perform diaphragmatic breathing exercises combined with diaphragmatic electrostimulation using KOTS currents. The intervention will last three weeks, with two sessions per week. The study will assess respiratory function, quality of life, physical function, dyspnea, fatigue, and basal oxygen saturation.
Read the detailed description
Long COVID is a multifactorial condition that may be associated with persistent respiratory symptoms, reduced physical capacity, fatigue, dyspnea, and impaired quality of life. Respiratory rehabilitation strategies may contribute to improving breathing patterns and functional recovery in this population. Diaphragmatic breathing exercises are commonly used to promote respiratory control and diaphragmatic activation. In addition, KOTS currents, also known as Russian currents, are medium-frequency alternating currents used in physiotherapy to elicit muscle contraction and may be applied as a complementary strategy to stimulate the diaphragm.
This pilot randomized controlled trial will compare diaphragmatic breathing exercises alone with diaphragmatic breathing exercises combined with diaphragmatic electrostimulation using KOTS currents in patients diagnosed with Long COVID. Participants will be randomly allocated to either the control group or the intervention group. Both groups will receive a three-week intervention consisting of two sessions per week. The control group will perform diaphragmatic breathing exercises, whereas the intervention group will perform the same breathing exercises combined with diaphragmatic electrostimulation.
Assessments will be conducted before and after the intervention period. The study is intended to explore whether adding diaphragmatic electrostimulation to a respiratory exercise program may provide additional benefits compared with diaphragmatic breathing exercises alone in this population.
- Conditions
- Long COVID Syndrome, Post-Acute COVID-19 Syndrome
- Being tested
- Diaphragmatic Electrostimulation Using KOTS Currents, Diaphragmatic Breathing Exercises
- Keywords
- Diaphragmatic Breathing, KOTS Currents, Russian Currents, Diaphragmatic Electrostimulation, Quality of Life, Respiratory Rehabilitation, Spirometry
- Medical subject headings
- Post-Acute COVID-19 Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Diaphragmatic Electrostimulation Using KOTS CurrentsDevice
Also called KOTS Currents, Russian Currents
Diaphragmatic electrostimulation will be applied using KOTS currents, a medium-frequency alternating current stimulation. Electrodes will be placed over the seventh and eighth rib region along the mammillary line. Stimulation will be delivered in trains of 4 seconds of stimulation followed by 8 seconds of rest, with a carrier frequency of 2,500 Hz. The standard treatment duration will be 15 minutes: 10 minutes at 30 Hz followed by 5 minutes at 70 Hz. Stimulation intensity will be adjusted according to participant tolerance. The intervention will be delivered twice per week for three weeks, together with diaphragmatic breathing exercises.
Diaphragmatic Breathing ExercisesBehavioural
Also called Diaphragmatic Breathing
Participants will perform diaphragmatic breathing exercises in a supine position with the knees flexed. One hand will be placed on the chest and the other hand below the sternum. Participants will be instructed to inhale through the nose while expanding the abdomen with minimal thoracic movement, and to exhale slowly through pursed lips. The breathing pattern will include a 4-second inspiration and a 6-second expiration. Exercises will be performed twice per week for three weeks.
| Study group | Role | What they receive |
|---|---|---|
| Diaphragmatic Breathing Exercises Plus KOTS Currents | Experimental | Participants assigned to this arm will perform diaphragmatic breathing exercises combined with diaphragmatic electrostimulation using KOTS currents. The intervention will be delivered twice per week for three weeks. KOTS currents will be applied as medium-frequency alternating current stimulation, with stimulation intensity adjusted according to participant tolerance. Receives: Device: Diaphragmatic Electrostimulation Using KOTS Currents; Behavioral: Diaphragmatic Breathing Exercises |
| Diaphragmatic Breathing Exercises | Active comparator | Participants assigned to this arm will perform diaphragmatic breathing exercises twice per week for three weeks. Exercises will be performed in a supine position, with slow nasal inspiration and abdominal expansion followed by slow exhalation through pursed lips. Receives: Behavioral: Diaphragmatic Breathing Exercises |
What is being measured
The primary outcome is the main question the study is designed to answer.
Forced Vital Capacity
Forced vital capacity will be assessed using spirometry. The outcome will evaluate the change in forced vital capacity from baseline to after the three-week intervention.
Measured: Baseline and 3 weeks
Secondary outcomes (8)
Forced Expiratory Volume in One Second
Forced expiratory volume in one second will be assessed using spirometry. The outcome will evaluate the change in FEV1 from baseline to after the three-week intervention.
Measured: Baseline and 3 weeks
Peak Expiratory Flow
Peak expiratory flow will be assessed using spirometry. The outcome will evaluate the change in PEF from baseline to after the three-week intervention.
Measured: Baseline and 3 weeks
FEV1/FVC Ratio
The FEV1/FVC ratio will be calculated from spirometry measurements. The outcome will evaluate the change in the FEV1/FVC ratio from baseline to after the three-week intervention.
Measured: Baseline and 3 weeks
Basal Oxygen Saturation
Basal oxygen saturation will be measured using a finger pulse oximeter. The outcome will evaluate the change in basal oxygen saturation from baseline to after the three-week intervention
Measured: Baseline and 3 weeks
Physical Function
Physical function will be assessed using the 30-second Sit-to-Stand test. The outcome will evaluate the change in the number of completed sit-to-stand repetitions from baseline to after the three-week intervention
Measured: Baseline and 3 weeks
Dyspnea
Dyspnea will be assessed using the modified Medical Research Council scale. The outcome will evaluate the change in perceived dyspnea from baseline to after the three-week intervention. Lower scores indicate lower dyspnea.
Measured: Baseline and 3 weeks
Quality of Life with SF-36 questionnaire
Quality of life will be assessed using the SF-36 questionnaire. The outcome will evaluate the change in quality-of-life dimensions from baseline to after the three-week intervention. Higher scores indicate better quality of life.
Measured: Baseline and 3 weeks
Fatigue
Fatigue will be assessed using the DePaul Symptom Questionnaire. Higher scores indicate greater fatigue.
Measured: Baseline and 3 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Jun 2026
- Study start14 Jun 2026
- Primary completion31 Jul 2026
- Study completion7 Aug 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Long COVID SyndromeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants will be randomly assigned to one of two parallel groups: diaphragmatic breathing exercises alone or diaphragmatic breathing exercises combined with diaphragmatic electrostimulation using KOTS currents.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 9 participants (actual)
Sponsor and investigators
- Lead sponsor
- Universidad Pontificia de Salamanca
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Sara Perpiñá, Universidad Pontificia de Salamanca
- Investigators
- Sara Perpiña-Martínez, Principal investigator, Pontifical University of Salamanca
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07621588
- Sponsor's protocol ID
- UPSA-KOTS-LC-2025
- Acronym
- KOTS-LC
- Status last verified
- Sep 2026
- First submitted
- 27 May 2026
- Last updated
- 29 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared because the study involves health-related data from a small sample of participants. Data will be pseudonymized and handled in accordance with applicable data protection regulations and the informed consent approved for the study.
Study at a glance
From the registry record, last updated by the sponsor on 29 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Diaphragmatic Breathing Exercises Combined With Diaphragmatic Electrostimulation Using KOTS Currents in Patients With Long COVID: A Pilot Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT07621588
- Acronym / sponsor ID
- KOTS-LC / UPSA-KOTS-LC-2025
- Conditions
- Long COVID Syndrome, Post-Acute COVID-19 Syndrome
- Keywords
- Diaphragmatic Breathing, KOTS Currents, Russian Currents, Diaphragmatic Electrostimulation, Quality of Life, Respiratory Rehabilitation, Spirometry
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 9 participants (actual)
- Lead sponsor
- Universidad Pontificia de SalamancaUniversity, hospital or other
- Study start
- 14 Jun 2026 (actual)
- Primary completion
- 31 Jul 2026 (actual)
- Study completion
- 7 Aug 2026 (actual)
- First posted
- 2 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study will evaluate the effects of diaphragmatic breathing exercises combined with diaphragmatic electrostimulation using KOTS currents in patients with Long COVID. Participants will be randomly assigned to one of two groups. The control group will perform diaphragmatic breathing exercises, while the intervention group will perform diaphragmatic breathing exercises combined with diaphragmatic electrostimulation using KOTS currents. The intervention will last three weeks, with two sessions per week. The study will assess respiratory function, quality of life, physical function, dyspnea, fatigue, and basal oxygen saturation.
Detailed description
Long COVID is a multifactorial condition that may be associated with persistent respiratory symptoms, reduced physical capacity, fatigue, dyspnea, and impaired quality of life. Respiratory rehabilitation strategies may contribute to improving breathing patterns and functional recovery in this population. Diaphragmatic breathing exercises are commonly used to promote respiratory control and diaphragmatic activation. In addition, KOTS currents, also known as Russian currents, are medium-frequency alternating currents used in physiotherapy to elicit muscle contraction and may be applied as a complementary strategy to stimulate the diaphragm.
This pilot randomized controlled trial will compare diaphragmatic breathing exercises alone with diaphragmatic breathing exercises combined with diaphragmatic electrostimulation using KOTS currents in patients diagnosed with Long COVID. Participants will be randomly allocated to either the control group or the intervention group. Both groups will receive a three-week intervention consisting of two sessions per week. The control group will perform diaphragmatic breathing exercises, whereas the intervention group will perform the same breathing exercises combined with diaphragmatic electrostimulation.
Assessments will be conducted before and after the intervention period. The study is intended to explore whether adding diaphragmatic electrostimulation to a respiratory exercise program may provide additional benefits compared with diaphragmatic breathing exercises alone in this population.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
- Model description
- Participants will be randomly assigned to one of two parallel groups: diaphragmatic breathing exercises alone or diaphragmatic breathing exercises combined with diaphragmatic electrostimulation using KOTS currents.
| Arm | Type | Receives |
|---|---|---|
| Diaphragmatic Breathing Exercises Plus KOTS Currents | Experimental | Device: Diaphragmatic Electrostimulation Using KOTS Currents, Behavioral: Diaphragmatic Breathing ExercisesParticipants assigned to this arm will perform diaphragmatic breathing exercises combined with diaphragmatic electrostimulation using KOTS currents. The intervention will be delivered twice per week for three weeks. KOTS currents will be applied as medium-frequency alternating current stimulation, with stimulation intensity adjusted according to participant tolerance. |
| Diaphragmatic Breathing Exercises | Active comparator | Behavioral: Diaphragmatic Breathing ExercisesParticipants assigned to this arm will perform diaphragmatic breathing exercises twice per week for three weeks. Exercises will be performed in a supine position, with slow nasal inspiration and abdominal expansion followed by slow exhalation through pursed lips. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Men and women aged 18 to 65 years.
- Medical diagnosis of Long COVID.
- At least 2 months since SARS-CoV-2 infection.
- Ability and willingness to provide informed consent.
- Ability to participate in the assigned intervention and assessment procedures.
Key exclusion criteria (10 listed)
- Presence of a pacemaker.
- History of epilepsy.
- Pregnancy.
- History of acute cardiac arrest.
- Severe respiratory distress.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Diaphragmatic Electrostimulation Using KOTS CurrentsAlso: KOTS Currents, Russian CurrentsDiaphragmatic electrostimulation will be applied using KOTS currents, a medium-frequency alternating current stimulation. Electrodes will be placed over the seventh and eighth rib region along the mammillary line. Stimulation will be delivered in trains of 4 seconds of stimulation followed by 8 seconds of rest, with a carrier frequency of 2,500 Hz. The standard treatment duration will be 15 minutes: 10 minutes at 30 Hz followed by 5 minutes at 70 Hz. Stimulation intensity will be adjusted according to participant tolerance. The intervention will be delivered twice per week for three weeks, together with diaphragmatic breathing exercises. | Device | Diaphragmatic Breathing Exercises Plus KOTS Currents |
| Diaphragmatic Breathing ExercisesAlso: Diaphragmatic BreathingParticipants will perform diaphragmatic breathing exercises in a supine position with the knees flexed. One hand will be placed on the chest and the other hand below the sternum. Participants will be instructed to inhale through the nose while expanding the abdomen with minimal thoracic movement, and to exhale slowly through pursed lips. The breathing pattern will include a 4-second inspiration and a 6-second expiration. Exercises will be performed twice per week for three weeks. | Behavioural | Diaphragmatic Breathing Exercises, Diaphragmatic Breathing Exercises Plus KOTS Currents |
Primary outcome
Forced Vital Capacity
Time frame: Baseline and 3 weeks
Forced vital capacity will be assessed using spirometry. The outcome will evaluate the change in forced vital capacity from baseline to after the three-week intervention.
8 secondary outcomes
Forced Expiratory Volume in One Second
Time frame: Baseline and 3 weeks
Peak Expiratory Flow
Time frame: Baseline and 3 weeks
FEV1/FVC Ratio
Time frame: Baseline and 3 weeks
Basal Oxygen Saturation
Time frame: Baseline and 3 weeks
Physical Function
Time frame: Baseline and 3 weeks
Dyspnea
Time frame: Baseline and 3 weeks
Quality of Life with SF-36 questionnaire
Time frame: Baseline and 3 weeks
Fatigue
Time frame: Baseline and 3 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Sep 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be shared because the study involves health-related data from a small sample of participants. Data will be pseudonymized and handled in accordance with applicable data protection regulations and the informed consent approved for the study.
Related trials for Long COVID Syndrome
Not yet recruitingPhase 1
Phase I Open-Label Safety Trial of Pembrolizumab for Neurological Post- Acute Sequelae of SARS-CoV-2 (PD1-PASC I)
Post-Acute COVID-19 Syndrome
Recruiting
Whole-body Cryotherapy in Those With Chronic Fatigue: A Feasibility Study
ME/CFS, Fibromyalgia (FM)
Not yet recruitingPhase 3
The Study of Brave-LC LDN Treatment Trial
Post-acute COVID-19 Syndrome
Active, not recruitingObservational study
Epigenetic Changes in Long COVID Patients
Long COVID-19 Syndrome, Long COVID Symptoms
Enrolling by invitationPhase 2
Immunotherapy for Neurological Post-Acute Sequelae of SARS-CoV-2
Systemic Inflammation, Neuroinflammation
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Sara Perpiña-Martínez principal investigator
Pontifical University of Salamanca
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Diaphragmatic Electrostimulation Using KOTS Currents and Diaphragmatic Breathing Exercises in people with Long COVID Syndrome and Post-Acute COVID-19 Syndrome, run by Universidad Pontificia de Salamanca at 1 site in Spain.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 29 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Spain. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Forced Vital Capacity (time frame: Baseline and 3 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Sep 2026.