Effects os Physiotherapeutic Rehabilitation on Cardiovascular Autonomic Modulation and Biomarkers Inflammatory and Cardiac Conditions in Patients With Long Covid
Phase: NA
Conditions: Long COVID, Heart Rate Variability (HRV), Cardiac Biomarkers, Inflammatory Biomarkers
Sponsor: Universidade do Estado do Pará

 
 
 
 
 
EFFECTS 
OF 
PHYSIOTHERAPEUTIC 
REHABILITATION 
ON 
CARDIOVASCULAR AUTONOMIC MODULATION AND INFLAMMATORY 
AND CARDIAC BIOMARKERS IN PATIENTS WITH LONG COVID 
 
 
Document Date: June 25, 2025. 

OBJECTIVES 
GENERAL OBJECTIVE 
● To assess the cardiac autonomic function of patients with long COVID-19 before 
and after a physiotherapy rehabilitation protocol. 
SPECIFIC OBJECTIVES 
 
● To draw up a profile of patients with long COVID-19 treated in a 
rehabilitation programme. 
● To investigate changes in cardiac biomarkers in patients with long 
COVID-19. 
● Associating linear and non-linear HRV variables with clinical data 
(hospitalisation, number of symptoms, post-Covid time). 
● Comparing the findings of autonomic modulation through linear and non- linear 
HRV variables at rest to inflammatory and cardiac biomarkers in different clinical 
groups of patients with Long COVID-19 
 
METHODOLOGY 
ETHICAL ASPECTS 
This study will be carried out as part of a project approved by the Research Ethics 
Committee (CEP) of the State University of Pará (UEPA) under opinion number 
4.288.736, which began in July 2020. This study will follow the precepts of the 
Declaration of Helsinki and the Nuremberg Code, respecting the rules of research 
involving human beings (CNS Res. 466/12 and 580/18) of the National Health Council. 
Participants will consent to the study by signing the Informed Consent Form (ICF). 
 
TYPE AND PLACE OF STUDY 
This is a controlled clinical trial on a local scale carried out in the cardiorespiratory 
diseases outpatient clinic at the Specialised Rehabilitation Centre (CERIII) in the 
Physiotherapy Teaching and Assistance Unit and 

Occupational Therapy (UEAFTO) at the State University of Pará (UEPA) on the CCBS 
campus. This study will be registered on clinicaltrials.com. 
 
SAMPLE CALCULATION AND SELECTION 
The sample calculation will be carried out using the GraphPad StatMate 
application (SOFTWARE GRAPHPAD, SAN, CALIFORNIA), version 1.01, with 
significance of 5% and a test power of 99% to determine the sample N. The study 
sample will include patients who were assessed, underwent the full rehabilitation 
protocol and were re-evaluated. Data will be collected from 2024 to 2026. Participants 
with a clinical diagnosis of Long COVID-19, with an indication for 
physiotherapy rehabilitation, will undergo the cardiopulmonary rehabilitation 
protocol, which consists of morning or afternoon care, twice a week totalling 20 
sessions. 
INCLUSION AND EXCLUSION CRITERIA 
 
Individuals with a confirmed diagnosis of COVID-19, of both sexes, aged between 
20 and 59 years, recovered, in clinical condition for evaluation and undergoing clinical 
follow-up of Post COVID-19 at UEPA will be included. The criteria considered for the 
diagnosis of Long COVID-19 follow the criteria proposed by RAVEENDRAN, 2020: (a) 
acute symptomatic phase of COVID-19 confirmed by quantitative polymerase chain 
reaction (RT-qPCR) - reverse transcription, with symptoms consistent with COVID-19 
not attributable to any other cause; and (b) at least one persistent COVID-19-related 
symptom, such as muscle weakness, chest pain, dyspnoea, fatigue, loss of balance, 
tremor, headache, myalgia, lower limb oedema, visual disturbances and/or insomnia, not 
attributable to another differential diagnosis, for at least four weeks after the onset of 
symptoms. 
Exclusion criteria will be as follows: incomplete data, presence of a pacemaker, 
use of antihypertensive drugs that alter HRV, persistent pulmonary alterations, persistent 
desaturation, anaemia or presence of reinfection. 

DATA COLLECTION 
Prior to collecting data for the study, demographic and clinical information will be 
extracted from an interview with each individual by filling out an electronic form, 
including information such as: age, weight (kg), height (m), body mass index (BMI), 
previous illnesses, hospitalisation, length of stay, use of oxygen therapy, invasive 
mechanical ventilation, symptoms of COVID-19, HRV collection, among others. 
Together, this information will also be useful for including or excluding patients in the 
study (APPENDIX B). 
HEART RATE VARIABILITY 
 
The instruments used to measure HRV will be the Polar®RS800CX device with 
WearLink heart rate sensor, the elastic strap, the interface with USB input and a computer. 
Participants will be instructed to abstain from caffeine, caffeine derivatives, heavy 
meals at least 24 hours before the test and strenuous physical activity. On the day of 
collection, the participant will rest for 15 minutes for haemodynamic stabilisation and 
then the HRV assessment will take place in accordance with the following steps: it will 
take place in the morning, in a quiet environment with a temperature between 22ºC and 
24Cº, and heart rate will be recorded for 10 minutes in the supine position (lying down) 
using a Polar® RS800CX cardiofrequency meter (Kempele, Finland) on previously 
moistened skin using a strap/electrode below the xiphoid process. The patient will be 
instructed not to talk, move or sleep during the collection to avoid interfering with the 
signal. 
In addition, vital signs will be collected (Heart Rate - HR; Respiratory Rate - RR; 
Blood Pressure - BP; Peripheral O2 Saturation - SpO2; Modified Borg Scale). A Lane 
Instruments® sphygmomanometer and a Bic® stethoscope will be used to collect 
systemic blood pressure (SBP). The Polar Pro Trainer 5 software (Polar Electro Ou, 
Finland) will then be used to capture the data. 
For this analysis, the 5-minute section with the most stable signal will be selected, 
discarding the initial 30 seconds and the final 30 seconds of the collection. The linear 
variables analysed for HRV in the 

of temporal frequencies in a specific routine according to Porta et al. (2001) will be the 
RR interval (iRR), Standard Deviation of all normal NN interval (SDNN), and Root-Mean 
of square successive NN interval difference (RMSSD), Percentage of Successive NN 
Intervals Differing by More Than 50 (PNN50), expressed in ms and the Stress Index (SI). 
In the frequency domain, the High Frequency (HF); Low Frequency (LF) and Ratio 
Between Low and High Frequency Components (LF/HF) will be analysed in normalised 
units (nu). 
The non-linear variables observed were Standard Deviation of Instantaneous us 
Variability Beat to Beat Variability (SD1), Standard Deviation of the Long-term 
Continuous RR Intervals (SD2), expressed in ms. 
 
LABORATORY TESTS 
 
The patient will undergo the test after an 8-hour fast at UEPA's Clinical Analysis 
Laboratory, where the blood samples will be collected and analysed. 3 mL of blood will 
be collected in two Vacuette® tubes (Greiner Bio-One, Kremsmünster, Austria), one of 
them with anticoagulant ethylenediaminetetraacetic acid, for whole blood analysis and 
the other tube with separator gel and clot activator for serum analysis. 
Cardiac function will be assessed by analysing creatine phosphokinase isoenzyme 
MB - CKMB (U/L), lactate dehydrogenase - LDH (U/L), C-reactive protein (CRP) and 
ferritin. 
5.4.3 PROCEDURES 
 
Stage 1: Approach eligible participants according to the inclusion criteria and interested 
parties after signing the informed consent form. 
Stage 2: Screening of patients by interview to collect demographic and clinical data in 
order to identify persistent symptoms of COVID-Longa infection, even after the isolation 
period. 
Stage 3: Participants will undergo laboratory tests and subsequent assessment of HRV 
and other tests required for physiotherapy rehabilitation. 

Stage 4: The participants underwent the physiotherapy protocol, which consisted of 
aerobic training (treadmill or exercise bike) for 15 minutes, anaerobic training at the 
weight training station, performing exercises for the upper limbs (bench press and front 
pull) and lower limbs (180º leg press and extension chair) with weight determined by the 
1 Repetition Maximum (1RM) test, performing 3 sets of 12-15 repetitions (depending on 
the session) and respiratory muscle training using POWERbreathe (30-40% of the MIP 
performed in the manovacuometry test). 
Stage 5: The participants will be reassessed and the variables collected will be compared 
in the pre- and post-protocol periods. In addition, these values will be compared with the 
predicted values of the tests found in the literature.

STATISTICAL ANALYSIS 
The collection data will be stored in Excel 2010™ software (Microsoft Corporation, 
Redmond, USA) and analyzed using Graphpad prism software version 5.0™ (Graphpad 
software, Inc., San Diego, USA). Student's t-test and ANOVA (analysis of variance) will 
be used to treat variables with normal distribution; Wilcoxon and McNemar will be used 
for variables that present an abnormal distribution, adopting a significance value of 
p< 
0.05 p. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
INFORMED CONSENT FORM (ICF) 
 
You are being invited to take part in the research project entitled: ‘Effects of 
Physiotherapy Rehabilitation on Cardiovascular Autonomic Modulation and on 
Inflammatory and Cardiac Biomarkers in Patients with Long COVID’. The study aims 
to promote a therapeutic proposal through a functional rehabilitation programme for 
patients with manifestations of Long COVID-19. 
 
I) The research will be carried out in room 17 at UEPA's Physiotherapy and Occupational 
Therapy Teaching and Assistance Unit (UEAFTO) on the CCBS campus. 
 
II) You will be subjected to a specific treatment protocol comprising monitored 
functional training, with the aim of improving your tolerance to exertion, as well as 
receiving health guidance on the disease, its limitations, treatments and quality of life. 
 
III) In this study, demographic and clinical data will be collected, as well as assessments. 
After selection, the 10-week treatment will take place twice a week, lasting an average 
of 50 minutes. Your vital signs (blood pressure, heart rate and respiratory rate) will be 
constantly checked. 
 
IV) The expected benefits for you are related to a possible reduction in symptoms and 
greater tolerance to physical exertion, since specific treatment will be offered and you 
will be able to perform better in your activities of daily living. 
 
V) The risks foreseen for you are related to intolerance to the proposed exercises, with 
alterations in monitoring signs such as heart rate, respiratory rate, blood pressure and 
peripheral oxygen saturation. If this occurs, the session will be interrupted until the signs 
and symptoms are fully restored and you will receive all the necessary support. Another 
risk you may face is the disclosure of your identity, but this risk will be minimised so 
that only the researchers have access to the information collected. 
 
VI) You will not incur any expenses for taking part in this research, nor will there be any 
financial compensation for your participation. Any and all information obtained during 
both the assessment and the treatment will be kept confidential. The data will be stored 
and analysed together with that of other interviewees, and the identification of any 
participant will not be disclosed; your name will not appear in any publication, thus 
preserving your privacy. 
 
VII) You can withdraw from the research at any time and this will not harm you in any 
way. 
 
VIII) At any stage of this study, you will have access to the professionals responsible for 
the research to clarify any doubts you may have. 

 
IX) This document is printed in two copies, one of which will remain with the researcher 
in charge and the other will be given to the participant. I would like to inform you that, 
at any time, you may seek clarification from the Researcher in Charge regarding the 
purpose of the research and the method and/or any other questions that may arise during 
the sessions. 
 
( ) I wish to know the results of this research. 
 
( ) I do not wish to know the results of this research. 
 
Belém,  
of  
de  
 
 
The Research Ethics Committee is responsible for the ethical monitoring of research 
involving human beings (Resolution 466/12) with the aim of guaranteeing the safety and 
well-being of research subjects. 
 
I,  
, have 
discussed my decision to take part in this study with the researcher. It has been made 
clear to me what the purposes are, the procedures to be carried out and the guarantees of 
confidentiality and ongoing clarification. I agree to participate voluntarily in this study. 
 
I declare that I have read the above information about the research, that I feel fully 
informed about its content, as well as its risks and benefits. I also declare that, of my own 
free will, I agree to take part in the research. 
 
Telephone: 
        
 
                                                                                  Participant's signature 
Researcher responsible: Luiz Fábio Magno Falcão 
Signature of Researcher in Charge:  
 
State University of Pará 
Telephone: +55 (91) 98237-9488  
E-mail: fabiofalcao29@yahoo.com.br 
 
Researcher: Suellen da Silva Mendonça 
Researcher's signature:  
 
State University of Pará  
Telephone: +55 (91) 99812-2193