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A Feasibility Study on a Multidisciplinary Rehabilitation Program Including Whole-Body Cryostimulation in Patients With Obesity and Post-COVID Condition

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23 October 2023

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24 October 2023

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Abstract
Background: Post-Covid condition can reduce activity and quality of life, resulting in a significant socioeconomic and health burden. Understanding its impact on patients' health is important for the development of personalized rehabilitation interventions. An independent association between obesity and post-covid condition was found because of complications and comorbidities. Methods: Sixteen patients with obesity and post-COVID symptoms (i.e., dyspnea, pain, poor sleep quality, muscle fatigue) admitted to the Istituto Auxologico Italiano, Piancavallo (VB), Italy, were recruited for a four-week rehabilitation program including conventional exercise therapy, nutritional intervention, psychological support and whole-body cryostimulation (WBC). Results: All participants attended all sessions of the program. Anthropometric data showed statistically significant changes in weight, waist circumference and body mass index. Biochemical analyses showed significant reductions in lipid and inflammatory profiles. There was a significant improvement in physical performance, reduction in pain and improvement in psychological well-being. Conclusion: A multidisciplinary rehabilitation protocol including WBC designed for patients with obesity and post-covid condition is safe and feasible. The overall improvements demonstrate that multidisciplinary rehabilitation was effective on post COVID patients and suggest that the use of WBC is safe and could play a role as a booster in rehabilitation programs.
Keywords: 
Subject: Medicine and Pharmacology  -   Clinical Medicine

1. Introduction

In December 2019, the world saw the emergence of Severe Acute Respiratory Syndrome Coronavirus 2 (Sars-CoV2), which can range from an asymptomatic infection to acute respiratory distress syndrome (ARDS) [1,2]. The new coronavirus disease 2019 (COVID-19) put health systems in serious difficulties, infecting over 635 million people with more than 6.6 million deaths [3,4]. Nowadays, as pandemic persists, more than 30% of people infected with COVID-19, including asymptomatic cases, and approximately 80% of patients hospitalized for COVID-19 have reported long COVID, or post COVID-19 condition (PCC) after infection [5]. PCC is defined as sequelae of symptoms that persist for at least 4 weeks after acute infection or 3 months after infection, for at least 2 months and that cannot be explained by other causes [6]. This condition is characterized by dyspnea, coughing, fever, and persistent loss of smell or taste which eventually combines with musculoskeletal (e.g., fatigue and myalgias) and psychological (e.g., concentration and memory disorders, depression, and anxiety) problems [5,7,8]. PCC could reduce activity ability and health-related quality of life (HR-QoL), imposing significant socioeconomic and health burdens, and has attracted widespread attention [9]. Understanding PCC impact on patients' health and well-being is of great importance in developing effective and personalized rehabilitation and pharmacological interventions [10,11].
In particular, obesity is linked to the progression of COVID-19 through a number of molecular pathways that increase SARS-CoV-2 infection vulnerability [12]. Adipose tissues in obese patients have a greater number of proteases and receptors for SARS-CoV-2 entry, suggesting that they could act as an accelerator and reservoir for this virus, enhancing the immune response and systemic inflammation [12].
Several studies have documented an independent association between obesity and PCC because of the complications and comorbidities, reporting a 25% higher risk of PCC with an additional burden on the immune system and involvement of physical and physiological processes [13,14,15]. Patients with obesity hospitalized in Intensive Care Units are more susceptible to PCC, with complaints of reduced activity capacity, cognition, and psychological function, like post-intensive care syndrome [16].
Other studies have reported that patients with prolonged COVID symptoms are more likely to have obesity and any obesity degree (BMI ≥30 kg/m2) was associated with a worse PCC prognosis [17]. Thus, an intensive multidisciplinary, tailored rehabilitation approach is required to maximize the patient’s functional recovery and facilitate the returning to pre-morbid life, especially when PCC symptoms appear to persist or even worsen in susceptible individuals [18].The rehabilitation treatments are intended to restore physical function, improve respiratory capacity, relieve symptoms of fatigue and pain, improve mental wellbeing and promote overall quality of life [19]. Conventional rehabilitative approaches for PCC include physiotherapy [19,20], breathing [21] and resistance and/or aerobic exercises [22,23], psychological counseling [24], and home-based programs [25].
Physical therapy in PCC focuses on improving physical strength, endurance, balance, and mobility, while respiratory therapy aims to improve lung function and breathing patterns [20]. Psychological counseling is essential to address the mental and emotional impact of PCC, including anxiety, depression, and post-traumatic stress disorder [24]. However, it is important to explore alternative interventions that can complement and enhance the conventional rehabilitation process.
Previous studies investigated Whole-Body Cryostimulation (WBC) as a treatment able to reduce pain and inflammatory status in several conditions [26,27] and to improve depression, anxiety [28], functional status and fatigue [29,30], and sleep quality [31]. WBC consists of expositions to cryogenic temperatures (-110°C to -140°C) for a short period of time (2-3 minutes) and is a therapy with widely recognized anti-inflammatory and less studied metabolic effects [32] which is used as a post-exercise recovery technique in elite athletes [33]. In addition, a growing number of works suggest that WBC could play a role as a highly promising adjuvant therapy in various conditions of rehabilitation interest [34,35]. In fact, treatments with WBC have been reported to relieve symptoms in different conditions (rheumatoid arthritis, fibromyalgia, ankylosing spondylitis, depression and anxiety, multiple sclerosis, sleep disturbances, muscle soreness after strenuous physical exercise, obesity) and the positive effects of ten serial sessions of WBC have been previously reported in patients with PCC [23,36].
The effect of adding WBC to a multidisciplinary rehabilitation program has not been studied extensively, particularly in the context of post-COVID care, although it is a unique approach [37]. The purpose of this study was to investigate the safety, acceptability and feasibility of a multidisciplinary personalized rehabilitation program including WBC in patients with obesity and PCC, admitted to a rehabilitation unit, and to provide additional data on cryostimulation as an adjuvant treatment for functional recovery.

2. Materials and Methods

2.1. Study design

A single arm longitudinal study was performed. According to the literature [38], feasibility studies are an attempt to answer questions about whether some aspect of a future trial is feasible, in this case the authors seek to determine the acceptability of an intervention and the perceived importance of types of outcomes. Acceptability can be interpreted as the participants' positive or negative opinion of a particular innovation. Patients were recruited from the Rehabilitation and Pneumology Unit of the San Giuseppe Hospital, Istituto Auxologico Italiano, Piancavallo (VB), Italy. The participants engaged in a 4-week multidisciplinary rehabilitation intervention. This study was conducted as part of a line of research aimed at defining better personalized rehabilitation programs for patients with obesity.

2.2. Participant Eligibility

Inclusion criteria were age 18-75 years, BMI≥30 kg/m2, PCC. Exclusion criteria were severe psychiatric illness, acute respiratory disease, acute cardiovascular disease, unstable hypertension, cold intolerance, claustrophobia, pregnancy, recent change in usual medication, previous treatment with WBC, weight loss in the previous 3 months, and body temperature >37.5°C.

2.3. Participants

Between July 2021 and September 2022, 16 patients admitted to the Rehabilitation and Pneumology Unit of the San Giuseppe Hospital, Istituto Auxologico Italiano, Piancavallo (VB), Italy, agreed to participate in the study.

2.4. Study Variables

Anthropometric data, cardiovascular parameters, blood tests and functional test scores were collected at baseline (T0) and within 4 weeks at the end of the rehabilitation protocol (T10).
A schematic diagram of the protocol can be found in Figure 1. There were no follow-up measurements after discharge. Anthropometric measurements included weight, height, body mass index (BMI) and waist circumference (WC). Cardiovascular parameters included heart rate (HR), systolic and diastolic blood pressure (SBP/DBP). Hematological biomarkers analyzed from blood samples taken in the morning under fasting conditions included glucose, total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides (TG) and C-reactive protein (CRP).
Physical performance tests included: a 6-minute walk test (6MWT) [39] and the Timed Up and Go test (TUG) [40]. General pain was assessed using the Visual Analogue Scale (VAS) [41].
The Psychological General Well-Being Index (PGWBI) was used to measure subjective psychological well-being [42].
Patients admitted to the respiratory unit had their basal SpO2 parameters measured by polysomnography on admission and discharge.

2.5. Intervention

The multidisciplinary rehabilitation program included individualized nutritional intervention, psychological support and supervised physical activity throughout the hospital stay. All patients received a balanced, hypocaloric Mediterranean diet consisting of three meals a day with 18-20% protein, 27-30% fat (of which < 8% saturated fat) and 50-55% carbohydrates (< 15% simple sugars), and 30 g of fiber from fresh vegetables. Under the supervision of a physiotherapist, two 60-minute physiotherapy sessions were performed daily, consisting of personalized progressive aerobic training, postural control exercises and progressive strengthening exercises. The aerobic sessions were monitored with subjective perception of fatigue (Borg's CR10 scale) and oxygen saturation (SpO2). Exercise was stopped when a score of 5 was reached on the Borg scale. The first aerobic session, performed in the morning after WBC, consisted of walking at a predetermined cadence. The second session, performed in the afternoon, consisted of arm cranking at an intensity of 65% of HRmax according to Karvonen's equation ((220 - age) × 0.65). This approach was individualized according to the patient's fitness, clinical status, and subjective perception of fatigue. All patients underwent ten sessions of WBC over a 2-week period (1 treatment per day, Monday to Friday, at 8:15 am, before exercise classes and physiotherapy).

2.6. Description of the WBC session

Subjects were exposed to extremely cold, dry air at -110°C for 2 minutes in a cryochamber (Arctic, CryoScience, Rome). On the day before the first WBC session, a 1-minute test session was performed. Sessions were conducted under the supervision of appropriately trained operators. On entering the cryochamber, the patients were asked to remove their glasses, contact lenses and jewelry, and to dry their bodies thoroughly to reduce the sensation of cold and avoid skin burns. Men were allowed to wear shorts or tracksuit bottoms (due to the severe cold sensation in some cases), a light t-shirt (or no shirt), mid-calf socks, clogs, gloves, headgear, and ear protection. Women also wore a sports bra or light t-shirt. A surgical mask covered the nose and mouth. Subjects were encouraged to shift their weight, move their fingers, and breathe normally in the cryochamber. Visual and vocal contact with the volunteers was constant. For safety reasons, SBP and DBP blood pressure was measured before and after each treatment.

2.7. Feasibility

Adherence to the 4-week protocol treatment was monitored, and completion rates of tests and questionnaires before and after the intervention were assessed. Adverse events were monitored throughout the study. At the end of the intervention, an exit interview was conducted to collect qualitative information about the participants' experience of the feasibility and effects of the intervention.

2.8. Statistical analysis

Statistical analysis was performed using Jamovi statistical software version 2.4.8. Data were expressed as mean (± standard deviation). Shapiro–Wilk test was used to evaluate the normality of the distribution of the data. Student's t test for normal data and Wilcoxon's nonparametric test for nonnormal data were used to compare admission and discharge data. The level of significance was set at p < 0.05.

2.9. Ethical considerations

Patients were fully informed of the scope and methodology of the study, which was conducted in accordance with the World Medical Association’s Declaration of Helsinki and approved by the Ethics Committee of Istituto Auxologico Italiano (reference: 2021_05_18_14). Written and verbal informed consent was obtained from all experimental patients.

3. Results

3.1. Participant Flow

From July 2021 to September 2022, a total of 16 patients (3 males, mean age 55.9 ± 7.51 years) met the eligibility criteria, were enrolled in this study (Figure 1) and started treatment. Eleven patients were recruited from the rehabilitation unit and five from the pneumology unit. All patients completed the study protocol. Anthropometric, hematological, and functional data at baseline (T0) are shown in Table 1.
Figure 2. Flowchart describing the number of patients the trial screened, enrolled, allocated, completed, and discontinued the intervention.
Figure 2. Flowchart describing the number of patients the trial screened, enrolled, allocated, completed, and discontinued the intervention.
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Admission and discharge data comparison

After the 4-week rehabilitation treatment, which included nutritional intervention, psychological support, supervised physical activity and WBC, the authors found the following changes. Anthropometric data showed statistically significant changes in weight, WC, and BMI, which were lower at discharge. Biochemical analyses showed a significant decrease in CRP, HDL, LDL, Tot Col, GLU at T10. Among the other parameters analyzed, no significant difference was found for TG at discharge. In terms of cardiovascular parameters there was a significant reduction in SBP and HR but not in DBP. There was a significant improvement in performance capacity as measured by TUG and distance walked on the 6MWT, a significant reduction in pain as shown by VAS pain, and an improvement in psychological well-being as measured by the PGWBI scale.
The patients hospitalized at the Pneumology unit showed significant improvements of Sp02 basal evaluation. A comprehensive overview of the results is provided in Table 2.

Feasibility

All 16 participants attended all four weekly sessions of the program, indicating excellent compliance. The data collection completion rate was good overall. No adverse events occurred during the intervention period. Participants reported positive physical and mental changes and were generally satisfied with the program setting. Motivation was very high due to the innovative nature of the approach included in the protocol.

4. Discussion

The present study demonstrates the safety and the feasibility of a multidisciplinary rehabilitation program combined with WBC and provides some preliminary evidence in patients with obesity and PCC. The correct diagnosis and management of PCC is challenging for healthcare providers due to the heterogeneity and complexity of clinical manifestations and the likely need for multidisciplinary management approaches [43,44,45].
The importance of identifying outcome measures in PCC rehabilitation, such as physical function, quality of life, general symptoms, disability, activities of daily living and return to work, is crucial [46]. Global assessment before and after a rehabilitation program should be undertaken to provide more evidence for the development of effective management plans for Long Covid patients [47], particularly in people at higher risk of developing more severe PCC, such as those with obesity [48].
In primary care, general practitioner prescription of physical activity in a safe environment with a trained facilitator, could be an extremely effective way to manage the symptoms of long COVID from the outset [49,50]. This prescription should be preceded by an initial consultation to identify comorbidities and risks such as post-exertional symptom exacerbation, which is characterized by a worsening of symptoms after physical or mental exertion, usually 12–48 hours after the activity and lasting for several days or (rarely) weeks [51].
Exercise-based rehabilitation is a therapeutic approach that may play an important role in improving sympathovagal balance and normalizing sympathetic index levels [52].
Several studies have focused on developing the most appropriate exercise protocol for patients with PCC, ranging from strength and endurance exercises to combined aerobic and resistance training [24,53,54], which can be varied in intensity and duration, and all show improvements in functional capacity [18,55].
According to our results, the effects of exercise therapy on SpO2 levels and cardiovascular fitness in patients with obesity and PCC have been widely documented [56]. Research has demonstrated the beneficial effects of exercise in reducing inflammation, improving immune function, and promoting overall physical and mental well-being in people with post-COVID condition [57,58,59].
Given the existing evidence of clinical and functional benefits following WBC in musculoskeletal, neurological, and psychological conditions, the addition of such treatment aims to improve the patient's overall physical performance and perceived quality of life [60]. Indeed, WBC is a safe and innovative method capable of applying precise and homogeneous "doses" of cold and inducing a rapid systematic reduction of inflammation and oxidative stress [61] with therapeutic effects on fatigue, pain [30], thymic tone, depression and sleep [27,28,30], as well as metabolic effects [32] such as increased thermogenesis and improved lipid profile, insulin sensitivity and glucose utilization, and could thus enhance the beneficial effects of an exercise program, especially one of short duration [62,63,64].
Thus, in line with our previous studies, the benefits of WBC appear to be rapid, from the very first sessions, probably due to its rapid anti-inflammatory effect [30,65,66]. So, implementing the WBC seems feasible and the pre/post results are encouraging as well.
Interestingly, an increase in parasympathetic tone is suggested by the significant reduction in HR observed. Autonomic dysfunction is a major hypothesis for symptom persistence in long COVID, and WBC may have a role to play as an adjuvant therapy as it can act as a 'training method' for the autonomic nervous system [67,68]. Indeed, it is well established that WBC is effective in increasing post-exercise and resting heart rate variability (HRV), an indicator of increased parasympathetic tone activation [69,70,71].
These findings may be of particular interest in cases in which rehabilitation programs may be hindered by pain, inflammation, or fatigue, and highlight the importance of early rehabilitation support.
To the best of our knowledge, this study includes the largest sample of PCC in patients with obesity undergoing multidisciplinary rehabilitation combined with WBC. Our results showed an improvement in patients' cardiometabolic profile and physical condition, as well as their overall quality of life by reducing chronic pain and inflammation.
Given its known rapid effects, WBC sessions started as early as a few days after admission and were performed early in the day with the aim of improving patients' overall physical performance and increasing adherence and motivation to rehabilitation. In addition, no adverse events were observed in the sample patients, indicating that this type of treatment can be performed safely.
Our data have some limitations, the main one being the lack of a control group for long-term COVID patients. This did not allow us to analyze both the evolution of treated patients with the natural evolution of symptoms, which is still unknown, and the effect of medical follow-up "alone”, in a dedicated facility and group. In addition, our results do not fully clarify the extent to which WBC can account for the improvements observed. As there is no control group, it is not possible to determine whether the results are due to WBC, to the multidisciplinary rehabilitation program, or a combination of the two.
In addition, the effects of WBC on the cardiovascular and respiratory systems in PCC are unclear and require further investigation. Another limitation was the small number of participants involved in the study therefore larger studies with diverse populations should be conducted to determine the generalizability of these findings to a wider range of patients with PCC. Due to the wide range of PCC symptoms, the sample was heterogeneous and consisted of different degrees of obesity, associated physical abilities and comorbidities. The reported results may have been influenced by motivational factors related to participation in a novel, well-tolerated treatment. Therefore, a randomized controlled trial with a control group is needed to formally investigate the effectiveness of the WBC intervention. Despite these limitations, the results of this feasibility study provide valuable insights into the potential efficacy and impact of a multidisciplinary rehabilitation program incorporating WBC in PCC patients with obesity.

5. Conclusions

This study shows that a comprehensive multidisciplinary rehabilitation protocol that includes WBC developed for patients with PCC and obesity is safe and feasible. The overall improvement in physical performance, hematological and metabolic parameters, psychological and general well-being, and pain demonstrates that exercise rehabilitation was an effective tool for long-term COVID patients and suggests that the use of WBC is safe and could play a role as a booster in rehabilitation programs. In addition, it is important to emphasize that the introduction of WBC was a turning point for all participants in terms of subjective and objective improvements in health and function, and that the overall improvement in clinical, physical, and biochemical parameters at discharge supports the use of WBC as an additional option in the multidisciplinary management of PCC. In conclusion, considering that the severity and prevalence of PCC in the general population is still high, the identification of rehabilitation programs and adjuvants that can act as a booster for rehabilitation programs appears to be of paramount importance. However, due to the heterogeneity of this condition, rehabilitation protocols should be tailored to each patient's needs. The small sample size makes it difficult to draw conclusions but underlines the importance of establishing a rehabilitation pathway for the care of patients with long COVID that can be adapted and tailored to the individual symptoms.

Author Contributions

Conceptualization, P.P., P.C., and J.M.F.; methodology, A.B., M.C., S.M. and S.C.; validation, A.B., J.M.F., and P.C.; investigation, A.A., F.V. and P.P.; data curation, A.A., J.M.F. and P.P.; writing—original draft preparation, A.A., F.V., J.M.F, and P.P.; writing—review and editing, A.A., A.B., J.M.F. and P.C.; visualization, A.B., M.C., and P.C.; supervision, M.C., P.C., S.C., A.B. and S.M.; funding acquisition, P.C. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by Italian Ministry of Health – Ricerca Corrente

Institutional Review Board Statement

The study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of Istituto Auxologico Italiano (reference: 2021_05_18_14).

Informed Consent Statement

Informed consent was obtained from all subjects involved in the study.

Data Availability Statement

Not applicable

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Brugliera, L.; Spina, A.; Castellazzi, P.; Cimino, P.; Tettamanti, A.; Houdayer, E.; Arcuri, P.; Alemanno, F.; Mortini, P.; Iannaccone, S. Rehabilitation of COVID-19 patients. J Rehabil Med 2020, 52, jrm00046. [Google Scholar] [CrossRef]
  2. Curci, C.; Pisano, F.; Bonacci, E.; Camozzi, D.M.; Ceravolo, C.; Bergonzi, R.; De Franceschi, S.; Moro, P.; Guarnieri, R.; Ferrillo, M.; et al. Early rehabilitation in post-acute COVID-19 patients: data from an Italian COVID-19 Rehabilitation Unit and proposal of a treatment protocol. Eur J Phys Rehabil Med 2020, 56, 633–641. [Google Scholar] [CrossRef] [PubMed]
  3. Aidalina, M.; Khalsom, S. COVID-19 vaccination: a systematic review of vaccination strategies based on economic evaluation studies. Med J Malaysia 2023, 78, 411–420. [Google Scholar]
  4. Beccia, F.; Di Pilla, A.; Causio, F.A.; Federico, B.; Specchia, M.L.; Favaretti, C.; Boccia, S.; Damiani, G. Narrative Review of the COVID-19 Pandemic's First Two Years in Italy. Int J Environ Res Public Health 2022, 19. [Google Scholar] [CrossRef] [PubMed]
  5. Ceban, F.; Ling, S.; Lui, L.M.W.; Lee, Y.; Gill, H.; Teopiz, K.M.; Rodrigues, N.B.; Subramaniapillai, M.; Di Vincenzo, J.D.; Cao, B.; et al. Fatigue and cognitive impairment in Post-COVID-19 Syndrome: A systematic review and meta-analysis. Brain Behav Immun 2022, 101, 93–135. [Google Scholar] [CrossRef] [PubMed]
  6. Hope, A.A.; Evering, T.H. Postacute Sequelae of Severe Acute Respiratory Syndrome Coronavirus 2 Infection. Infect Dis Clin North Am 2022, 36, 379–395. [Google Scholar] [CrossRef] [PubMed]
  7. Ferioli, M.; Prediletto, I.; Bensai, S.; Betti, S.; Daniele, F.; Di Scioscio, V.; Modolon, C.; Rimondi, M.R.; De Molo, C.; Serra, C.; et al. Spontaneous Evolution of COVID-19 Lung Sequelae: Results from a Double-Step Follow-Up. Respiration 2022, 101, 381–393. [Google Scholar] [CrossRef]
  8. Gupta, A.; Madhavan, M.V.; Sehgal, K.; Nair, N.; Mahajan, S.; Sehrawat, T.S.; Bikdeli, B.; Ahluwalia, N.; Ausiello, J.C.; Wan, E.Y.; et al. Extrapulmonary manifestations of COVID-19. Nat Med 2020, 26, 1017–1032. [Google Scholar] [CrossRef]
  9. Lau, B.; Wentz, E.; Ni, Z.; Yenokyan, K.; Coggiano, C.; Mehta, S.H.; Duggal, P. Physical and mental health disability associated with long-COVID: Baseline results from a US nationwide cohort. medRxiv 2022. [Google Scholar] [CrossRef]
  10. Pouliopoulou, D.V.; Macdermid, J.C.; Saunders, E.; Peters, S.; Brunton, L.; Miller, E.; Quinn, K.L.; Pereira, T.V.; Bobos, P. Rehabilitation Interventions for Physical Capacity and Quality of Life in Adults With Post-COVID-19 Condition: A Systematic Review and Meta-Analysis. JAMA Netw Open 2023, 6, e2333838. [Google Scholar] [CrossRef]
  11. Alito, A.; Rodolico, C.; Palco, M.; Portaro, S. Steroid Management in a Patient with Myasthenia Gravis Undergoing COVID-19 Vaccination. Innov Clin Neurosci 2022, 19, 8. [Google Scholar] [PubMed]
  12. Behl, T.; Kumar, S.; Singh, S.; Bhatia, S.; Albarrati, A.; Albratty, M.; Meraya, A.M.; Najmi, A.; Bungau, S. Reviving the mutual impact of SARS-COV-2 and obesity on patients: From morbidity to mortality. Biomed Pharmacother 2022, 151, 113178. [Google Scholar] [CrossRef] [PubMed]
  13. Fernandez-de-Las-Penas, C.; Torres-Macho, J.; Elvira-Martinez, C.M.; Molina-Trigueros, L.J.; Sebastian-Viana, T.; Hernandez-Barrera, V. Obesity is associated with a greater number of long-term post-COVID symptoms and poor sleep quality: A multicentre case-control study. Int J Clin Pract 2021, 75, e14917. [Google Scholar] [CrossRef] [PubMed]
  14. Shyam, S.; Gomez-Martinez, C.; Paz-Graniel, I.; Gaforio, J.J.; Martinez-Gonzalez, M.A.; Corella, D.; Fito, M.; Martinez, J.A.; Alonso-Gomez, A.M.; Warnberg, J.; et al. Coronavirus disease 2019 is associated with long-term depressive symptoms in Spanish older adults with overweight/obesity and metabolic syndrome. Psychol Med 2023, 1–11. [Google Scholar] [CrossRef]
  15. Varallo, G.; Suso-Ribera, C.; Ghiggia, A.; Veneruso, M.; Cattivelli, R.; Guerrini Usubini, A.; Franceschini, C.; Musetti, A.; Plazzi, G.; Fontana, J.M.; et al. Catastrophizing, Kinesiophobia, and Acceptance as Mediators of the Relationship Between Perceived Pain Severity, Self-Reported and Performance-Based Physical Function in Women with Fibromyalgia and Obesity. J Pain Res 2022, 15, 3017–3029. [Google Scholar] [CrossRef] [PubMed]
  16. Aburto, S.; Cisterna, M.; Acuna, J.; Ruiz, C.; Viscardi, S.; Marquez, J.L.; Villano, I.; Letelier, P.; Guzman, N. Obesity as a Risk Factor for Severe COVID-19 in Hospitalized Patients: Epidemiology and Potential Mechanisms. Healthcare (Basel) 2022, 10. [Google Scholar] [CrossRef] [PubMed]
  17. Raman, B.; Bluemke, D.A.; Luscher, T.F.; Neubauer, S. Long COVID: post-acute sequelae of COVID-19 with a cardiovascular focus. Eur Heart J 2022, 43, 1157–1172. [Google Scholar] [CrossRef]
  18. Colas, C.; Le Berre, Y.; Fanget, M.; Savall, A.; Killian, M.; Goujon, I.; Labeix, P.; Bayle, M.; Feasson, L.; Roche, F.; et al. Physical Activity in Long COVID: A Comparative Study of Exercise Rehabilitation Benefits in Patients with Long COVID, Coronary Artery Disease and Fibromyalgia. Int J Environ Res Public Health 2023, 20. [Google Scholar] [CrossRef]
  19. Zheng, C.; Chen, X.K.; Sit, C.H.; Liang, X.; Ming-Hui, L.I.; Ma, A.C.; Wong, S.H. Effect of Physical Exercise-Based Rehabilitation on Long COVID: A Systematic Review and Meta-analysis. Med Sci Sports Exerc 2023. [Google Scholar] [CrossRef]
  20. Jimeno-Almazan, A.; Franco-Lopez, F.; Buendia-Romero, A.; Martinez-Cava, A.; Sanchez-Agar, J.A.; Sanchez-Alcaraz Martinez, B.J.; Courel-Ibanez, J.; Pallares, J.G. Rehabilitation for post-COVID-19 condition through a supervised exercise intervention: A randomized controlled trial. Scand J Med Sci Sports 2022, 32, 1791–1801. [Google Scholar] [CrossRef] [PubMed]
  21. McNarry, M.A.; Berg, R.M.G.; Shelley, J.; Hudson, J.; Saynor, Z.L.; Duckers, J.; Lewis, K.; Davies, G.A.; Mackintosh, K.A. Inspiratory muscle training enhances recovery post-COVID-19: a randomised controlled trial. Eur Respir J 2022, 60. [Google Scholar] [CrossRef]
  22. Saha, S.; Sharma, K. Modification of Lifestyle to Recover from Post-COVID Symptoms: A Short Review. J Lifestyle Med 2022, 12, 113–118. [Google Scholar] [CrossRef]
  23. Gobbi, M.; Bezzoli, E.; Ismelli, F.; Trotti, G.; Cortellezzi, S.; Meneguzzo, F.; Arreghini, M.; Seitanidis, I.; Brunani, A.; Aspesi, V.; et al. Skeletal Muscle Mass, Sarcopenia and Rehabilitation Outcomes in Post-Acute COVID-19 Patients. J Clin Med 2021, 10. [Google Scholar] [CrossRef]
  24. Araujo, B.T.S.; Barros, A.; Nunes, D.T.X.; Remigio de Aguiar, M.I.; Mastroianni, V.W.; de Souza, J.A.F.; Fernades, J.; Campos, S.L.; Brandao, D.C.; Dornelas de Andrade, A. Effects of continuous aerobic training associated with resistance training on maximal and submaximal exercise tolerance, fatigue, and quality of life of patients post-COVID-19. Physiother Res Int 2023, 28, e1972. [Google Scholar] [CrossRef]
  25. Cerfoglio, S.; Capodaglio, P.; Rossi, P.; Verme, F.; Boldini, G.; Cvetkova, V.; Ruggeri, G.; Galli, M.; Cimolin, V. Tele-Rehabilitation Interventions for Motor Symptoms in COVID-19 Patients: A Narrative Review. Bioengineering (Basel) 2023, 10. [Google Scholar] [CrossRef]
  26. Fontana, J.M.; Bozgeyik, S.; Gobbi, M.; Pitera, P.; Giusti, E.M.; Dugue, B.; Lombardi, G.; Capodaglio, P. Whole-body cryostimulation in obesity. A scoping review. J Therm Biol 2022, 106, 103250. [Google Scholar] [CrossRef] [PubMed]
  27. Fontana, J.M.; Gobbi, M.; Piterà, P.; Giusti, E.M.; Capodaglio, P. Whole-Body Cryostimulation in Fibromyalgia: A Scoping Review. Applied Sciences 2022, 12(9) 4794. [CrossRef]
  28. Rymaszewska, J.; Ramsey, D.; Chladzinska-Kiejna, S. Whole-body cryotherapy as adjunct treatment of depressive and anxiety disorders. Arch Immunol Ther Exp (Warsz) 2008, 56, 63–68. [Google Scholar] [CrossRef] [PubMed]
  29. Miller, E.; Kostka, J.; Wlodarczyk, T.; Dugue, B. Whole-body cryostimulation (cryotherapy) provides benefits for fatigue and functional status in multiple sclerosis patients. A case-control study. Acta Neurol Scand 2016, 134, 420–426. [Google Scholar] [CrossRef]
  30. Varallo, G.; Pitera, P.; Fontana, J.M.; Gobbi, M.; Arreghini, M.; Giusti, E.M.; Franceschini, C.; Plazzi, G.; Castelnuovo, G.; Capodaglio, P. Is Whole-Body Cryostimulation an Effective Add-On Treatment in Individuals with Fibromyalgia and Obesity? A Randomized Controlled Clinical Trial. J Clin Med 2022, 11. [Google Scholar] [CrossRef] [PubMed]
  31. Douzi, W.; Dupuy, O.; Tanneau, M.; Boucard, G.; Bouzigon, R.; Dugue, B. 3-min whole body cryotherapy/cryostimulation after training in the evening improves sleep quality in physically active men. Eur J Sport Sci 2019, 19, 860–867. [Google Scholar] [CrossRef] [PubMed]
  32. White, G.E.; Wells, G.D. Cold-water immersion and other forms of cryotherapy: physiological changes potentially affecting recovery from high-intensity exercise. Extrem Physiol Med 2013, 2, 26. [Google Scholar] [CrossRef]
  33. Rose, C.; Edwards, K.M.; Siegler, J.; Graham, K.; Caillaud, C. Whole-body Cryotherapy as a Recovery Technique after Exercise: A Review of the Literature. Int J Sports Med 2017, 38, 1049–1060. [Google Scholar] [CrossRef]
  34. Kujawski, S.; Zalewski, P.; Godlewska, B.R.; Cudnoch-Jedrzejewska, A.; Murovska, M.; Newton, J.L.; Sokolowski, L.; Slomko, J. Effects of whole-body cryotherapy and static stretching are maintained 4 weeks after treatment in most patients with chronic fatigue syndrome. Cryobiology 2023, 112, 104546. [Google Scholar] [CrossRef]
  35. Poignard, M.; Guilhem, G.; Jubeau, M.; Martin, E.; Giol, T.; Montalvan, B.; Bieuzen, F. Cold-water immersion and whole-body cryotherapy attenuate muscle soreness during 3 days of match-like tennis protocol. Eur J Appl Physiol 2023, 123, 1895–1909. [Google Scholar] [CrossRef] [PubMed]
  36. Piterà, P.; Gobbi, M.; Fontana, J.M.; Cattaldo, S.; Massucci, M.; Capodaglio, P. Whole-Body Cryostimulation: A Rehabilitation Booster in Post-COVID Patients? A Case Series. Applied Sciences 2022, 12, 4830. [Google Scholar] [CrossRef]
  37. Gobbi, M.; Trotti, G.; Tanzi, M.; Kasap, F.; Pitera, P.; Capodaglio, P. Post-Covid Symptoms and Whole-Body Cryotheraphy: A Case Report. J Rehabil Med Clin Commun 2022, 5, 1000075. [Google Scholar] [CrossRef] [PubMed]
  38. Eldridge, S.M.; Lancaster, G.A.; Campbell, M.J.; Thabane, L.; Hopewell, S.; Coleman, C.L.; Bond, C.M. Defining Feasibility and Pilot Studies in Preparation for Randomised Controlled Trials: Development of a Conceptual Framework. PLoS One 2016, 11, e0150205. [Google Scholar] [CrossRef]
  39. Enright, P.L. The six-minute walk test. Respir Care 2003, 48, 783–785. [Google Scholar] [PubMed]
  40. Bohannon, R.W. Reference values for the timed up and go test: a descriptive meta-analysis. J Geriatr Phys Ther 2006, 29, 64–68. [Google Scholar] [CrossRef]
  41. Gift, A.G. Visual analogue scales: measurement of subjective phenomena. Nurs Res 1989, 38, 286–288. [Google Scholar] [CrossRef]
  42. Lundgren-Nilsson, A.; Jonsdottir, I.H.; Ahlborg, G., Jr.; Tennant, A. Construct validity of the Psychological General Well Being Index (PGWBI) in a sample of patients undergoing treatment for stress-related exhaustion: a Rasch analysis. Health Qual Life Outcomes 2013, 11, 2. [Google Scholar] [CrossRef] [PubMed]
  43. Hoeg, T.B.; Ladhani, S.; Prasad, V. How methodological pitfalls have created widespread misunderstanding about long COVID. BMJ Evid Based Med 2023. [Google Scholar] [CrossRef] [PubMed]
  44. Parker, A.M.; Brigham, E.; Connolly, B.; McPeake, J.; Agranovich, A.V.; Kenes, M.T.; Casey, K.; Reynolds, C.; Schmidt, K.F.R.; Kim, S.Y.; et al. Addressing the post-acute sequelae of SARS-CoV-2 infection: a multidisciplinary model of care. Lancet Respir Med 2021, 9, 1328–1341. [Google Scholar] [CrossRef] [PubMed]
  45. Sardella, A.; Chiara, E.; Alibrandi, A.; Bellone, F.; Catalano, A.; Lenzo, V.; Quattropani, M.C.; Basile, G. Changes in Cognitive and Functional Status and in Quality of Life of Older Outpatients during the COVID-19 Pandemic. Gerontology 2022, 68, 1285–1290. [Google Scholar] [CrossRef] [PubMed]
  46. Munblit, D.; Nicholson, T.; Akrami, A.; Apfelbacher, C.; Chen, J.; De Groote, W.; Diaz, J.V.; Gorst, S.L.; Harman, N.; Kokorina, A.; et al. A core outcome set for post-COVID-19 condition in adults for use in clinical practice and research: an international Delphi consensus study. Lancet Respir Med 2022, 10, 715–724. [Google Scholar] [CrossRef] [PubMed]
  47. Leisman, D.E.; Ronner, L.; Pinotti, R.; Taylor, M.D.; Sinha, P.; Calfee, C.S.; Hirayama, A.V.; Mastroiani, F.; Turtle, C.J.; Harhay, M.O.; et al. Cytokine elevation in severe and critical COVID-19: a rapid systematic review, meta-analysis, and comparison with other inflammatory syndromes. Lancet Respir Med 2020, 8, 1233–1244. [Google Scholar] [CrossRef] [PubMed]
  48. Vimercati, L.; De Maria, L.; Quarato, M.; Caputi, A.; Gesualdo, L.; Migliore, G.; Cavone, D.; Sponselli, S.; Pipoli, A.; Inchingolo, F.; et al. Association between Long COVID and Overweight/Obesity. J Clin Med 2021, 10. [Google Scholar] [CrossRef]
  49. Greenhalgh, T.; Sivan, M.; Delaney, B.; Evans, R.; Milne, R. Long covid-an update for primary care. BMJ 2022, 378, e072117. [Google Scholar] [CrossRef]
  50. Wahlgren, C.; Divanoglou, A.; Larsson, M.; Nilsson, E.; Ostholm Balkhed, A.; Niward, K.; Birberg Thornberg, U.; Lilliecreutz Gudmundsson, E.; Levi, R. Rehabilitation needs following COVID-19: Five-month post-discharge clinical follow-up of individuals with concerning self-reported symptoms. EClinicalMedicine 2022, 43, 101219. [Google Scholar] [CrossRef]
  51. Decary, S.; Gaboury, I.; Poirier, S.; Garcia, C.; Simpson, S.; Bull, M.; Brown, D.; Daigle, F. Humility and Acceptance: Working Within Our Limits With Long COVID and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. J Orthop Sports Phys Ther 2021, 51, 197–200. [Google Scholar] [CrossRef]
  52. De Maria, B.; Lucini, D.; Gois, M.O.; Catai, A.M.; Perego, F.; Malacarne, M.; Pagani, M.; Porta, A.; Dalla Vecchia, L.A. Improvement of Sympathovagal Balance by Regular Exercise May Counteract the Ageing Process. A Study by the Analysis of QT Variability. Front Physiol 2022, 13, 880250. [Google Scholar] [CrossRef] [PubMed]
  53. de Sire, A.; Andrenelli, E.; Negrini, F.; Lazzarini, S.G.; Cordani, C.; Ceravolo, M.G.; International Multiprofessional Steering Committee of Cochrane Rehabilitation, R. E.H.C.A. Rehabilitation and COVID-19: update of the rapid living systematic review by Cochrane Rehabilitation Field as of February 28th, 2022. Eur J Phys Rehabil Med 2022, 58, 498–501. [Google Scholar] [CrossRef]
  54. Udina, C.; Ars, J.; Morandi, A.; Vilaro, J.; Caceres, C.; Inzitari, M. Rehabilitation in adult post-COVID-19 patients in post-acute care with Therapeutic Exercise. J Frailty Aging 2021, 10, 297–300. [Google Scholar] [CrossRef] [PubMed]
  55. Cattadori, G.; Di Marco, S.; Baravelli, M.; Picozzi, A.; Ambrosio, G. Exercise Training in Post-COVID-19 Patients: The Need for a Multifactorial Protocol for a Multifactorial Pathophysiology. J Clin Med 2022, 11. [Google Scholar] [CrossRef] [PubMed]
  56. Lemos, M.M.; Cavalini, G.R.; Pugliese Henrique, C.R.; Perli, V.A.S.; de Moraes Marchiori, G.; Marchiori, L.L.M.; Sordi, A.F.; Franzoi de Moraes, S.M.; de Paula Ramos, S.; Valdes-Badilla, P.; et al. Body composition and cardiorespiratory fitness in overweight or obese people post COVID-19: A comparative study. Front Physiol 2022, 13, 949351. [Google Scholar] [CrossRef] [PubMed]
  57. Xiang, M.; Wu, X.; Jing, H.; Novakovic, V.A.; Shi, J. The intersection of obesity and (long) COVID-19: Hypoxia, thrombotic inflammation, and vascular endothelial injury. Front Cardiovasc Med 2023, 10, 1062491. [Google Scholar] [CrossRef]
  58. Zakynthinos, G.E.; Stavrou, V.T.; Malli, F.; Papathanasiou, I.V.; Zakynthinos, E.; Gourgoulianis, K.I.; Kalabakas, K.; Karagiannis, D.; Basdekis, G. The Effect of Whole-Body Cryostimulation in Healthy Adults : Whole-Body Cryostimulation According to Gender and Smoking Status. Adv Exp Med Biol 2021, 1337, 315–321. [Google Scholar] [CrossRef]
  59. Cerfoglio, S.; Capodaglio, P.; Rossi, P.; Verme, F.; Boldini, G.; Cvetkova, V.; Galli, M.; Cimolin, V. Inertialbased Six-Minute Walking Test Assessment in Post-Covid Patients: Preliminary Results. In Proceedings of the EUROCON 2023 - 20th International Conference on Smart Technologies, Proceedings, Torino, 6 July 2023through 8 July 2023, 2023; pp. 520 - 524.
  60. Tabisz, H.; Modlinska, A.; Kujawski, S.; Slomko, J.; Zalewski, P. Whole-body cryotherapy as a treatment for chronic medical conditions? Br Med Bull 2023, 146, 43–72. [Google Scholar] [CrossRef]
  61. Pilch, W.; Piotrowska, A.; Wyrostek, J.; Czerwinska-Ledwig, O.; Ziemann, E.; Antosiewicz, J.; Zasada, M.; Kulesa-Mrowiecka, M.; Zychowska, M. Different Changes in Adipokines, Lipid Profile, and TNF-Alpha Levels between 10 and 20 Whole Body Cryostimulation Sessions in Individuals with I and II Degrees of Obesity. Biomedicines 2022, 10. [Google Scholar] [CrossRef]
  62. Alito, A.; Quartarone, A.; Leonardi, G.; Tisano, A.; Bruschetta, A.; Cucinotta, F.; Milardi, D.; Portaro, S. Brown adipose tissue human biomarkers: Which one fits best? A narrative review. Medicine (Baltimore) 2022, 101, e32181. [Google Scholar] [CrossRef]
  63. Hanssen, M.J.; van der Lans, A.A.; Brans, B.; Hoeks, J.; Jardon, K.M.; Schaart, G.; Mottaghy, F.M.; Schrauwen, P.; van Marken Lichtenbelt, W.D. Short-term Cold Acclimation Recruits Brown Adipose Tissue in Obese Humans. Diabetes 2016, 65, 1179–1189. [Google Scholar] [CrossRef]
  64. Wiecek, M.; Szymura, J.; Sproull, J.; Szygula, Z. Whole-Body Cryotherapy Is an Effective Method of Reducing Abdominal Obesity in Menopausal Women with Metabolic Syndrome. J Clin Med 2020, 9. [Google Scholar] [CrossRef]
  65. Capodaglio, P.; Cremascoli, R.; Pitera, P.; Fontana, J.M. Whole-Body Cryostimulation: A Rehabilitation Booster. J Rehabil Med Clin Commun 2022, 5, 2810. [Google Scholar] [CrossRef]
  66. Verme, F.; Scarpa, A.; Varallo, G.; Pitera, P.; Capodaglio, P.; Fontana, J.M. Effects of Whole-Body Cryostimulation on Pain Management and Disease Activity in Active Rheumatic Polymyalgia: A Case-Report. Biomedicines 2023, 11. [Google Scholar] [CrossRef]
  67. Allendes, F.J.; Diaz, H.S.; Ortiz, F.C.; Marcus, N.J.; Quintanilla, R.; Inestrosa, N.C.; Del Rio, R. Cardiovascular and autonomic dysfunction in long-COVID syndrome and the potential role of non-invasive therapeutic strategies on cardiovascular outcomes. Front Med (Lausanne) 2022, 9, 1095249. [Google Scholar] [CrossRef]
  68. Dani, M.; Dirksen, A.; Taraborrelli, P.; Torocastro, M.; Panagopoulos, D.; Sutton, R.; Lim, P.B. Autonomic dysfunction in 'long COVID': rationale, physiology and management strategies. Clin Med (Lond) 2021, 21, e63–e67. [Google Scholar] [CrossRef]
  69. Hausswirth, C.; Schaal, K.; Le Meur, Y.; Bieuzen, F.; Filliard, J.R.; Volondat, M.; Louis, J. Parasympathetic activity and blood catecholamine responses following a single partial-body cryostimulation and a whole-body cryostimulation. PLoS One 2013, 8, e72658. [Google Scholar] [CrossRef]
  70. Louis, J.; Theurot, D.; Filliard, J.R.; Volondat, M.; Dugue, B.; Dupuy, O. The use of whole-body cryotherapy: time- and dose-response investigation on circulating blood catecholamines and heart rate variability. Eur J Appl Physiol 2020, 120, 1733–1743. [Google Scholar] [CrossRef]
  71. Zalewski, P.; Bitner, A.; Slomko, J.; Szrajda, J.; Klawe, J.J.; Tafil-Klawe, M.; Newton, J.L. Whole-body cryostimulation increases parasympathetic outflow and decreases core body temperature. J Therm Biol 2014, 45, 75–80. [Google Scholar] [CrossRef]
Figure 1. Schematic of the study design showing the timeline of the study protocol and research outcomes.
Figure 1. Schematic of the study design showing the timeline of the study protocol and research outcomes.
Preprints 88512 g001
Table 1. Baseline clinical and demographic characteristics (N=16).
Table 1. Baseline clinical and demographic characteristics (N=16).
Mean SD Mean SD
Age (y) 55.94 ±7.50 CRP (mg/L) 0.57 ±0.54
Weight (kg) 99.83 ±29.19 HDL (mg/dL) 49.37 ±11.41
BMI (kg/m2) 37.99 ±8.44 LDL (mg/dL) 130.50 ±40.94
WC (cm) 114.40 ±13.99 Tot. Col. (mg/dL) 196.96 ±49.06
LOS (d) 30.6 ±7.69 TG (mg/dL) 156.62 ±51.38
6MWT (m) 381.80 ±145.05 Glu (mg/dL) 112.25 ±40.70
TUG (s) 12.65 ±11.65 SBP (mmHg) 135.0 ±19.0
VAS pain 53.06 ±26.64 DBP (mmHg) 81.3 ±11.9
PGWBI 63.50 ±16.92 HR (bpm) 80.0 ±10.4
6MWT, 6-Minute Walk Test; BMI, Body Mass Index; bpm, beat per minute; CRP, C-Reactive Protein; DBP, Diastolic Blood Pressure; HDL, high-density lipoprotein; HR, Heart Rate; LDL, Low-Density Lipoprotein; LOS, Length of Stay; PGWBI, Psychological General Well-Being Index; SBP, Systolic Blood Pressure; SpO2, Saturation of Peripheral Oxygen; TG, triglycerides; Tot Col., Total Cholesterol; TUG, Timed Up and Go test; VAS, Visual Analogue Scale; WC, Waist Circumference.
Table 2. Comparison between the parameters at T0 and at T10 (N=16).
Table 2. Comparison between the parameters at T0 and at T10 (N=16).
T0 T10 p-Value
Weight (kg) 99.83 ±29.19 95.819 ±27.10 < .001
BMI (kg/m2) 37.99 ±8.44 36.491 ±7.81 < .001
WC (cm) 114.40 ±13.99 108.800 ±13.73 0.002
6MWT (m) 381.80 ±145.05 446.200 ±84.56 0.093
TUG (s) 12.65 ±11.65 9.373 ±4.67 0.009
VAS pain 53.06 ±26.64 33.938 ±18.71 < .001
PGWBI 63.50 ±16.92 76.188 ±16.59 0.002
CRP (mg/L) 0.57 ±0.54 0.459 ±0.41 0.013
HDL (mg/dL) 49.37 ±11.41 43.688 ±9.90 < .001
LDL (mg/dL) 130.50 ±40.94 107.563 ±47.00 0.005
Tot. Col. (mg/dL) 196.96 ±49.06 176.838 ±56.51 0.013
TG (mg/dL) 156.62 ±51.38 147.438 ±49.77 0.473ᵇ
Glu (mg/dL) 112.25 ±40.70 97.563 ±17.94 0.003
SBP (mmHg) 135.0 ±19.0 125.625 ±14.59 0.046
DBP (mmHg) 81.3 ±11.9 76.250 ±5.00 0.084ᵇ
HR (bpm) 80.0 ±10.4 73.188 ±5.50 0.014
SpO2 * 91.5 ±1.47 94.0 ±2.05 0.047
a, Wilcoxon test; b, t-Student test. * Only patients admitted to Pneumology Unit.6MWT, 6-Minute Walk Test; BMI, Body Mass Index; bpm, beat per minute; CRP, C-Reactive Protein; DBP, Diastolic Blood Pressure; HDL, high-density lipoprotein; HR, Heart Rate; LDL, Low-Density Lipoprotein; PGWBI, Psychological General Well-Being Index; SBP, Systolic Blood Pressure; SpO2, Saturation of Peripheral Oxygen; TG, triglycerides; Tot. Col., Total Cholesterol; TUG, Timed Up and Go test; VAS, Visual Analogue Scale; WC, Waist Circumference
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