Comparison of High-Intensity Interval Training to Moderate-Intensity Continuous Training for Functioning and Quality of Life in Survivors of COVID-19 (COVIDEX): Protocol for a Randomized Controlled Trial.

OBJECTIVE: The purpose of this study was to compare high-intensity interval training (HIIT) with moderate-intensity continuous training (MICT) for feasibility, safety, adherence, and short- and long-term efficacy in improving functioning and health-related quality of life in survivors of coronavirus disease 2019 (COVID-19). METHODS: COVIDEX is a two-pronged, parallel-group, randomized controlled trial with an 8-week training intervention. The study participants will be 94 patients aged >18 years, admitted to a specialized post-COVID center. Participants will be randomized to HIIT (4 × 4 minutes of high-intensity work periods at 85% to 90% of peak heart rate) and MICT (47 minutes at 70% to 75% peak heart rate) groups for biweekly sessions for 8 weeks. The participants will undergo 2 phases of supervised training (phases 1 and 2) of 4 weeks each, in a public, specialized, post-COVID center. In phase 1, we will assess and compare the feasibility, acceptability, and short-term efficacy of HIIT and MICT intervention. In phase 2, the long-term efficacy of HIIT and MICT will be assessed and compared regarding function and health-related quality of life. To prevent any expectation bias, all study participants and assessors will be blinded to the study hypotheses. Group allocation will be masked during the analysis. All statistical analyses will be conducted following intention-to-treat principles. IMPACT: This study is the first randomized controlled trial that will compare the feasibility, safety, adherence, and efficacy of the HIIT and MICT intervention programs in this population. The findings will potentially provide important information and assist in clinical decision making on exercise to optimize the benefits of clinical health care in survivors of COVID-19.

Effects of Taiwan's COVID-19 alert levels on the physical activity behaviors and psychological distress of community-dwelling older adults.

BACKGROUND: The Taiwanese government implemented stringent preventative health measures to curb the spread of COVID-19. However, these measures negatively affected the physical activity behaviors and psychological distress of individuals. In this study, we investigated the effects of Taiwan's COVID-19 alert-based restrictions on the physical activity behaviors and psychological distress of community-dwelling older adults. METHODS: In this longitudinal study, 500 community-dwelling older adults were randomly sampled from a health promotion center in Taiwan. Telephone interviews were conducted between May 11, 2021, and August 17, 2021, which coincided with the Level 3 alert period when group physical activities were prohibited. Telephone interviews were again conducted between June 20, 2022, and July 4, 2022, after the alert level was reduced to Level 2 but group physical activities were prohibited period. Through the telephone interviews, data regarding the participants' physical activity behaviors (type and amount) and 5-item Brief Symptom Rating Scale (BSRS-5) scores were collected. Moreover, data regarding physical activity behaviors were collected from the records of our previous health promotion programs, which were conducted before the national alert period. The obtained data were analyzed. RESULTS: The alert levels influenced physical activity behaviors. Because of strict regulations, physical activity amount decreased during the Level 3 alert period and did not recover rapidly during the Level 2 alert period. Instead of engaging in group exercises (e.g., calisthenics and qigong), the older adults chose to exercise alone (e.g., strolling, brisk walking, and biking). Our findings indicate that the COVID-19 alert level has a significant influence on the amount of physical activity for participants (p < 0.05, partial η2 = 0.256), with pairwise comparisons showing that the physical activity amount decreased significantly across the three time periods (p < 0.05). The psychological distress of the participants did not appear to change during the regulation period. Although the participants' overall BSRS-5 score was slightly lower during the Level 2 alert period compared to the Level 3 alert period, the difference was not statistically significant (p = 0.264, Cohen's d = 0.08) based on a paired t-test. However, the levels of anxiety (p = 0.003, Cohen's d = 0.23) and inferiority (p = 0.034, Cohen's d = 0.159) were considerably higher during the Level 2 alert period than during the Level 3 alert period. CONCLUSIONS: Our findings indicate that Taiwan's COVID-19 alert levels influenced the physical activity behaviors and psychological distress of community-dwelling older adults. Time is required for older adults to regain their prior status after their physical activity behaviors and psychological distress were affected by national regulations.

[Hospitalary concurrent exercise program in overweight and obese school students and adolescents during COVID-19 pandemic]. / Programa de ejercicio concurrente hospitalario en escolares y adolescentes con sobrepeso y obesidad durante la pandemia COVID-19.

The COVID-19 pandemic reduced daily physical activity in the pediatric population, with deleterious effects on anthropometry, muscle function, aerobic capacity, and metabolic control. OBJECTIVE: Determine the changes in anthropometry, aerobic capacity, muscle function, and metabolic control of a 12-week concurrent training protocol in overweight and obese children and adolescents during the COVID-19 pandemic. PATIENTS AND METHOD: 24 patients participated and were divided into groups once a week (12S; n = 10) and twice a week (24S; n = 14). Anthropometry, muscle function, aerobic capacity, and metabolic biochemical tests were evaluated before and after the application of the concurrent training plan. Two-way ANOVA, Kruskal-Wallis test, and Fisher's post hoc test were used. RESULTS: Only the twice times week training improved the anthropometrics parameters (BMI - z, waist circumference and waist to height ratio). The muscle function tests (push up, standing broad jump and prone plank), improved in both groups such as the aerobic capacity measured by VO2maximo and the runned distance in Shuttle 20m run test. The HOMA index only improved with twice times week training without changes in lipid profile in both groups. CONCLUSIONS: The 12S and 24S groups improved aerobic capacity and muscular function. Only the 24S improved anthropometric parameters and the HOMA index.

Pasos Hacia La Salud II: study protocol for a randomized controlled trial of a theory- and technology-enhanced physical activity intervention for Latina women, compared to the original intervention.

BACKGROUND: Latinas are at increased risk for many lifestyle-related chronic diseases and are one of the least physically active populations in the US Innovative strategies are needed to help Latinas achieve the health benefits associated with physical activity (PA). This manuscript describes the study protocol of the Pasos Hacia La Salud II Study, which builds upon our previous research to test an enhanced individually-tailored, text-message and website-delivered, Spanish-language intervention (enhanced intervention), in comparison to the original web-based Pasos Hacia La Salud Intervention (original intervention). METHODS: Sedentary Latinas between the ages of 18-65 will be recruited and will complete an orientation and baseline assessments. Participants will be subsequently randomized to the original intervention, or the Enhanced Intervention, which has greater targeting of theoretical constructs such as self-efficacy, enjoyment, and social support, and which uses text messages and more dynamic and refined website features to encourage increased website use. Using a linear mixed effects regression model, we will simultaneously estimate the intervention effects on mean accelerometer-measured hours/week of moderate-to-vigorous PA (MVPA) at 6, 12, 18, and 24 months, with a subject-specific intercept (intent-to-treat sample). Change in self-reported MVPA, measured via the 7-day Physical Activity Recall, will be assessed as a secondary outcome using a similar model. We will investigate potential mediators of the intervention effect using a multiple mediation approach, and potential moderators by evaluating potential interactions. As an exploratory outcome, we will study the differences (among both study arms) in cost, in US dollars, per minute increases in weekly mean MVPA. DISCUSSION: The original Pasos PA intervention showed efficacy in helping Latinas increase PA; we expect the Enhanced Intervention to help a larger proportion of participants to increase and maintain their PA long term. This web- and text-based enhanced intervention could have great reach and dissemination potential, which could be capitalized on in the future to help to advance health equity. Adaptations made in response to the COVID-19 pandemic are also described in this manuscript. TRIAL REGISTRATION: Clinical Trial Number: NCT03491592 . First posted April 9, 2018.

Impact of probiotic supplementation on exercise endurance among non-elite athletes: study protocol for a randomized, placebo-controlled, double-blind, clinical trial.

BACKGROUND: Some probiotics appear to improve athletic performance, endurance, and recovery after intense exercise. Other formulations may provide performance-related benefits via immune and gastrointestinal functions in athletic individuals. However, few formulations have been studied for both types of effects among non-elite athletes. The primary objective of this study is to assess the ergogenic effects of a probiotic on high-intensity endurance running performance in non-elite runners. Secondary objectives include assessment of perceived exertion, blood chemistry, immune and stress biomarkers, cold and flu symptoms, and gastrointestinal health after the probiotic intervention. METHODS: This 9-week randomized, placebo-controlled, double-blind, parallel trial will assess the ergogenic effects of a probiotic (5 billion colony-forming units/day, for 6 weeks) in healthy, non-elite runners (N=32; 18-45 years). Participants will be monitored via daily and weekly questionnaires during the 2-week pre-baseline, 6-week intervention, and 1-week washout. Questionnaires will inquire about activity, muscle soreness, gastrointestinal symptoms, cold and flu symptoms, stool form and frequency, and adverse events. During the pre-baseline visit, maximal oxygen uptake (V̇O2 max) is assessed to set appropriate individualized workload settings for the treadmill time-to-exhaustion endurance tests. These time-to-exhaustion endurance running tests will be completed at an intensity of 85% VO2max at baseline and final visits. During these tests, self-perceived exercise effort will be rated via the Borg Rating of Perceived Exertion scale and finger sticks assessing capillary blood glucose and lactate concentrations will be collected every 3 min. Additional questionnaires will assess diet and motivation to exercise. Body composition will be assessed using air displacement plethysmography at the baseline and final visits. Hypotheses will be tested using two-sided tests, and a linear model and with a type I error rate of α=0.05. Primary and secondary outcomes will be tested by comparing results between the intervention groups, adjusting for baseline values. DISCUSSION: These results will build evidence documenting the role of probiotics on running endurance performance and physiological responses to exercise in non-elite athletes. Understanding the potential mechanisms of probiotic effects and how they mitigate the intestinal or immune discomforts caused by running could provide additional strategy means to help runners improve their performance. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov NCT04588142 . Posted on October 19, 2020. PROTOCOL VERSION: July 2, 2021, version 1.2.

The impact of adolescents' health motivation on the relationship among mental stress, physical exercise, and stress symptoms during COVID-19: A dual moderation model.

Objective: Many Chinese teenagers are experiencing high mental stress levels due to epidemic-related restrictions and closures. Mental stress can induce numerous associated symptoms, and physical exercise is considered to buffer mental stress. However, it remains unclear whether health motivation regulates the relationships among mental stress, physical exercise, and stress symptoms. This study examined whether mental stress events during the epidemic can predict stress symptoms, whether physical exercise can buffer mental stress, and whether the mental stress buffer effect is enhanced when health motivation regarding physical exercise is high. Methods: In total, 2,420 junior high school students (1,190 boys and 1,230 girls; 826 seventh-grade students, 913 eighth-grade students, and 681 ninth-grade students) from nine provinces nationwide were selected to investigate mental stress events, symptoms, health motivation, and physical exercise in adolescents. The hypothesis was tested with a multiple regression analysis. Results: A positive relationship between adolescent mental stress events and stress symptoms was observed, and an interactive relationship was found among health motivation, physical exercise, and mental stress factors. Specifically, the mental stress-buffering effect of physical exercise was significant only when health motivation was high. Conclusion: In the post-epidemic period, the influence of mental stress events on stress symptoms in adolescents was found to be buffered by physical exercise only in terms of high health motivation. This result highlighted the role of health motivation in the buffering effect of physical exercise on mental stress during an epidemic.

Impaired Neuromuscular Efficiency and Symptom-Limited Aerobic Exercise Capacity 4 Weeks After Recovery From COVID-19 Appear to Be Associated With Disease Severity at Onset.

OBJECTIVE: The objectives of this study were to evaluate neuromuscular recruitment and efficiency in participants who recovered from COVID-19 and assess the association between neuromuscular efficiency and symptom-limited aerobic exercise capacity. METHODS: Participants who recovered from mild (n = 31) and severe (n = 17) COVID-19 were evaluated and compared with a reference group (n = 15). Participants underwent symptom-limited ergometer exercise testing with simultaneous electromyography evaluation after a 4-week recovery period. Activation of muscle fiber types IIa and IIb and neuromuscular efficiency (watts/percentage of root-mean-square obtained at the maximum effort) were determined from electromyography of the right vastus lateralis. RESULTS: Participants who had recovered from severe COVID-19 had lower power output and higher neuromuscular activity than the reference group and those who had recovered from mild COVID-19. Type IIa and IIb fibers were activated at a lower power output in participants who had recovered from severe COVID-19 than in the reference group and those who had recovered from mild COVID-19, with large effect sizes (0.40 for type IIa and 0.48 for type IIb). Neuromuscular efficiency was lower in participants who had recovered from severe COVID-19 than in the reference group and those who had recovered from mild COVID-19, with a large effect size (0.45). Neuromuscular efficiency showed a correlation with symptom-limited aerobic exercise capacity (r = 0.83). No differences were observed between participants who had recovered from mild COVID-19 and the reference group for any variables. CONCLUSION: This physiological observational study supports the notion that more severe COVID-19 symptoms at disease onset appear to correspondingly impair neuromuscular efficiency in survivors over a short time frame of 4 weeks after recovery, potentially contributing to reduced cardiorespiratory capacity. Further studies are needed to replicate and extend these findings with respect to their clinical implications for assessment/evaluation and interventions. IMPACT: After 4 weeks of recovery, neuromuscular impairment is particularly evident in severe cases; this problem may contribute to reduced cardiopulmonary exercise capacity.

Home-based exercise improves quality of life in breast and prostate cancer survivors: A meta-analysis.

BACKGROUND: Breast (BCa) and prostate (PCa) cancer are two of the most common but survivable cancers. One important component of survivorship that is impacted by treatment long term is diminished quality of life (QoL). Supervised exercise improves QoL and subsequent outcomes but is not accessible for all survivors. Additionally, many factors influence QoL including physical activity (PA), cardiorespiratory fitness (CRF), physical function, and fatigue. However, the COVID-19 pandemic has highlighted the need to increase access to exercise beyond supervised exercise facilities. Home-based exercise may provide a feasible alternative for cancer survivors especially for those living in rural communities. OBJECTIVES: The primary aim is to investigate the effects of home-based exercise training (Pre-training vs. Post-training) on QoL in BCa/PCa. A secondary aim is to investigate PA, CRF, physical function, and fatigue and potential moderators (age, cancer-type, intervention duration and type). Home-based exercise trials (randomized crossover or quasi-experimental design) with adults (aged 18 years and over) breast or prostate cancer survivors (not currently undergoing chemotherapy or radiation treatment) were eligible for inclusion. DATA SOURCES: Electronic databases were searched (inception-December 2022) for studies which included adult BCa or PCa survivors (not currently on chemotherapy/radiation), at least measured QoL, and undergoing unsupervised, home-based exercise training. APPRAISAL AND SYNTHESIS METHODS: Initially, 819 studies were identified, from which 17 studies (20 effects) involving 692 participants were extracted. Effect sizes were calculated as standardized mean differences (SMD). Data were pooled using a 3-level model with restricted maximum likelihood estimation. Pooled SMD was used to assess the magnitude of effect, where <0.2, 0.2, 0.5, and 0.8 was defined as trivial, small, moderate, and large respectively. RESULTS: Home-based exercise resulted in small improvements in QoL (SMD = 0.30, 95% CI 0.01, 0.60, p = 0.042), PA (SMD = 0.49, 95% CI 0.26, 0.75, p<0.001) and CRF (SMD = 0.45, 95% CI -0.01, 0.91, p = 0.056). Physical function (SMD = 0.00, 95% CI -0.21, 0.21, p = 1.000) and fatigue (SMD = -0.61, 95%CI -1.53, 0.32, p = 0.198) did not change. CONCLUSIONS: Home-based exercise results in small improves QoL in BCa/PCa survivors, independent of cancer type, intervention duration and type, or age. Home-based exercise also improves PA and CRF enhancing survivorship. Therefore, home-based exercise is an efficacious alternative option to improve QoL for BCa and PCa survivors especially for those who live in rural communities or lack access to exercise facilities.

Associations of Physical Inactivity and COVID-19 Outcomes Among Subgroups.

INTRODUCTION: Physical activity before COVID-19 infection is associated with less severe outcomes. The study determined whether a dose‒response association was observed and whether the associations were consistent across demographic subgroups and chronic conditions. METHODS: A retrospective cohort study of Kaiser Permanente Southern California adult patients who had a positive COVID-19 diagnosis between January 1, 2020 and May 31, 2021 was created. The exposure was the median of at least 3 physical activity self-reports before diagnosis. Patients were categorized as follows: always inactive, all assessments at 10 minutes/week or less; mostly inactive, median of 0-60 minutes per week; some activity, median of 60-150 minutes per week; consistently active, median>150 minutes per week; and always active, all assessments>150 minutes per week. Outcomes were hospitalization, deterioration event, or death 90 days after a COVID-19 diagnosis. Data were analyzed in 2022. RESULTS: Of 194,191 adults with COVID-19 infection, 6.3% were hospitalized, 3.1% experienced a deterioration event, and 2.8% died within 90 days. Dose‒response effects were strong; for example, patients in the some activity category had higher odds of hospitalization (OR=1.43; 95% CI=1.26, 1.63), deterioration (OR=1.83; 95% CI=1.49, 2.25), and death (OR=1.92; 95% CI=1.48, 2.49) than those in the always active category. Results were generally consistent across sex, race and ethnicity, age, and BMI categories and for patients with cardiovascular disease or hypertension. CONCLUSIONS: There were protective associations of physical activity for adverse COVID-19 outcomes across demographic and clinical characteristics. Public health leaders should add physical activity to pandemic control strategies.

Feasibility and acceptability of at-home play kits for middle school physical activity promotion during the COVID-19 pandemic.

BACKGROUND: Schools are central to providing opportunities for youth physical activity (PA), however such opportunities were limited during the COVID-19 pandemic. Identifying feasible, acceptable, and effective approaches for school-based PA promotion amid pandemic-related barriers can inform resource allocation efforts in future circumstances necessitating remote instruction. The aims of this study were to: (1) describe the pragmatic, stakeholder-engaged and theory-informed approach employed to adapt one school's PA promotion efforts to pandemic restrictions, leading to the creation of at-home "play kits" for students, and (2) assess the feasibility, acceptability, and preliminary effectiveness of this intervention. METHODS: Intervention activities occurred in one middle school (enrollment: 847) located in a Federal Opportunity Zone in the Seattle, WA area, with control data from a nearby middle school (enrollment: 640). Students at the intervention school were eligible to receive a play kit during the quarter they were enrolled in physical education (PE) class. Student surveys were completed across the school year (n = 1076), with a primary outcome of days/week that the student engaged in ≥ 60 min of PA. Qualitative interviews (n = 25) were conducted with students, staff, parents, and community partners, and focused on play kit acceptability and feasibility. RESULTS: During remote learning play kits were received by 58% of eligible students. Among students at the intervention school only, students actively enrolled in PE (versus not enrolled) reported significantly more days with ≥ 60 min of PA in the previous week, however the comparison between schools was not statistically significant. In qualitative interviews, most students reported the play kit motivated them to participate in PA, gave them activity ideas, and made virtual PE more enjoyable. Student-reported barriers to using play kits included space (indoors and outdoors), requirements to be quiet at home, necessary but unavailable adult supervision, lack of companions to play outdoors, and inclement weather. CONCLUSIONS: A pre-existing community organization-school partnership lent itself to a rapid response to meet student needs at a time when school staff and resources were highly constrained. The intervention developed through this collaborative response-play kits-has potential to support middle school PA during future pandemics or other conditions that necessitate remote schooling, however modifications to the intervention concept and implementation strategy may be needed to improve reach and effectiveness.

Effect of Online Home-Based Resistance Exercise Training on Physical Fitness, Depression, Stress, and Well-Being in Middle-Aged Persons: A Pilot Study.

PURPOSE: This study investigated the effect of online home-based resistance exercise training on fitness, depression, stress, and well-being. A total of 67 individuals participated. Of them, 28 participants (13 men and 15 women, average age: 45.1 ± 12.2 years) performed the same exercise training online (n = 17), using Zoom, or in person (n = 11) in 2020 (Study 1). In addition, 39 participants (15 men and 24 women; average age: 47.6 ± 10.8 years) performed eight weeks of online home-based resistance exercise training in 2021 (Study 2). The participants performed low-load resistance exercises twice a week for eight weeks (16 sessions). Muscle strength, thigh muscle cross-sectional area, fitness parameters, blood pressure, mental health (Center for Epidemiologic Studies-Depression Scale-CES-D; and Kessler Psychological Distress scale-K6), and well-being (Well-Being Index-WHO-5) were measured pre-and post-resistance training. In Study 1, eight weeks of online home-based resistance training improved CES-D (p = 0.003), and a similar tendency was observed in resistance training (RT) with the in-person group (p = 0.06). There was a significant improvement in CES-D symptoms after the online home-based resistance training in Study 2 (p = 0.009). However, there were no significant changes in the WHO-5 and K6. Our results suggest that online low-load resistance training improves fitness parameters and curbs depressive status.

Associations between Coronavirus and Immune Response, Cardiorespiratory Fitness Rehabilitation and Physical Activity: A Brief Report.

COVID-19 has serious effects on cardiorespiratory capacity. In this sense, physical activity has been identified as beneficial in the treatment of cardiorespiratory diseases due to its anti-inflammatory and immunosuppressive benefits. To date, no study has been found on cardiorespiratory capacity and rehabilitation in patients cured after COVID-19. Thus, this brief report aims to relate the benefits of physical activity to cardiorespiratory function after COVID-19. It is important to know how different levels of physical activity can be related to the different symptoms of COVID-19. In view of this, the objectives of this brief report were to: (1) explore the theoretical associations between COVID-19 symptoms and physical activity; (2) compare the cardiorespiratory function of non-COVID-19 participants and post-COVID-19 patients; and (3) propose a physical activity program to improve the cardiorespiratory fitness of post-COVID-19 patients. Thus, we note that moderate-intensity physical activity (i.e., walking) has a greater beneficial effect on immune function, whereas vigorous activity (i.e., marathon running) tends to temporarily reduce immune function through an imbalance of cytokine types I and II in the hours and days after exercise. However, there is no consensus in the literature in this regard, since other investigations suggest that high-intensity training can also be beneficial, not causing clinically relevant immunosuppression. Physical activity has been shown to be beneficial in improving the clinical conditions most frequently associated with severe COVID-19. Thus, it is possible to infer that physically active individuals seem to be less exposed to the dangers of severe COVID-19 compared to non-active individuals through the benefits of physical activity in strengthening the immune system and fighting infections. The current study demonstrates that physical activity appears to be beneficial in improving the clinical conditions most often associated with severe COVID-19.

The effects of a yoga intervention on balance and flexibility in female college students during COVID-19: A randomized controlled trial.

Female college students are more likely to have a strong stress response to the COVID-19 pandemic, which seriously affects their health and merits greater attention. The present study is a randomized controlled trial carried out during the COVID-19 pandemic. The purpose of this study was to explore whether a yoga intervention could have a positive impact on balance and flexibility and be the primary form of home exercise for female college students in China. Forty female college students were randomly selected for the study. After 16 weeks of yoga intervention, the ability of the yoga group to balance on one leg improved by 5.35 seconds (using the single-limb stance test) and 5.7 seconds (using the Romberg test). The flexibility of the lower back and legs increased by 3.5 cm (using the sit and reach test), and the flexibility of the groin and hip increased by 6 cm (using the Splits test). The balance ability and flexibility of the control group before and after the experiment were not significantly different (p>0.05). These results suggest that during the COVID-19 outbreak when access to public facilities was limited, a yoga intervention could have a positive impact on health and be the main form of home exercise for female college students. Schools and government departments could design online yoga classes to encourage individuals to actively participate in yoga to stay healthy.

Does Physical Exercise Enhance the Immune Response after Vaccination? A Systematic Review for Clinical Indications of COVID-19 Vaccine.

BACKGROUND: Stimulating protective immunity with vaccines appears to be the most promising option for providing widespread moderate to high protection against COVID-19 in people over the age of 18. Regular exercise improves the immune response, transmitting possible benefits against virus infections. The aim of this review is to study the effects of physical activity on vaccine injections, helping to develop new recommendations for COVID-19 vaccination campaigns. METHODS: A comprehensive review of the existing literature was undertaken using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The internal quality of the studies was assessed according to the Physiotherapy Evidence Database (PEDro) scale. The outcomes analyzed were antibody titer, the level of lymphocytes CD4, CD8, InterLeukin 6 (IL6), leukocytes level, the visual analogue scale (VAS) for overall pain rating, arm and forearm circumferences and volume of oxygen (VO2) peak. RESULTS: Fourteen articles were selected for the analysis. The majority of studies were randomized controlled trials (RCT) (n = 8) and controlled trials (CT) (n = 6). According to PEDro, the 'fair' category (n = 7) was the most represented, followed by 'good' (n = 6) and 'excellent' (n = 1). Physical training showed a positive effect on antibody titers of the vaccine; yet, different variables seem to influence antibody titers: higher new vs. old antigen in the vaccine, higher in younger vs. older individuals, and higher in females vs. males. After exercise, when analyzing variables of direct response to the vaccine, such as the amount of CD4, IL-6 and leukocytes, higher levels were observed in the patients who performed physical exercise compared to the control group. In the same way, better results were observed in physiological variables such as VO2 and limb circumferences, or subjective variables such as pain, which showed better results than the control group. CONCLUSIONS: The immune response (antibody titers) depends on age, gender and the intensity of physical activity: long-term protocols at moderate intensity are the most recommended. All of these aspects also have to be carefully considered for the COVID-19 vaccination.

Physical exercise, immune response, and susceptibility to infections-current knowledge and growing research areas.

This review presents state-of-the-art knowledge and identifies knowledge gaps for future research in the area of exercise-associated modifications of infection susceptibility. Regular moderate-intensity exercise is believed to have beneficial effects on immune health through lowering inflammation intensity and reducing susceptibility to respiratory infections. However, strenuous exercise, as performed by professional athletes, may promote infection: in about half of athletes presenting respiratory symptoms, no causative pathogen can be identified. Acute bouts of exercise enhance the release of pro-inflammatory mediators, which may induce infection-like respiratory symptoms. Relatively few studies have assessed the influence of regularly repeated exercise on the immune response and systemic inflammation compared to the effects of acute exercise. Additionally, ambient and environmental conditions may modify the systemic inflammatory response and infection susceptibility, particularly in outdoor athletes. Both acute and chronic regular exercise influence humoral and cellular immune response mechanisms, resulting in decreased specific and non-specific response in competitive athletes. The most promising areas of further research in exercise immunology include detailed immunological characterization of infection-prone and infection-resistant athletes, examining the efficacy of nutritional and pharmaceutical interventions as countermeasures to infection symptoms, and determining the influence of various exercise loads on susceptibility to infections with respiratory viruses, including SARS-CoV-2. By establishing a uniform definition of an "elite athlete," it will be possible to make a comparable and straightforward interpretation of data from different studies and settings.

Cardiovascular, Respiratory, and Functional Effects of Home-Based Exercise Training after COVID-19 Hospitalization.

INTRODUCTION: The present randomized, single-center, and single-blinded clinical trial tested the hypothesis that tele-supervised home-based exercise training (exercise) is an effective strategy for improving cardiovascular, respiratory, and functional capacity parameters in individuals who were hospitalized due to coronavirus disease 2019 (COVID-19). METHODS: Thirty-two individuals (52 ± 10 yr; 17 were female) randomly assigned to exercise ( n = 12) or control groups ( n = 20) had their anthropometric (weight, body mass index), hemodynamic (brachial and central blood pressure), vascular (arterial stiffness), ventilatory (pulmonary function and respiratory muscle strength), and functional parameters (handgrip strength, five-time sit to stand, timed up and go test, and 6-min walking test) assessed at baseline (30-45 d of hospital discharged) and after 12 wk of follow-up. RESULTS: Both groups similarly increased ( P < 0.001) forced vital capacity (absolute and percent of predicted), forced expiratory volume in the first second (absolute and percent of predicted), and handgrip strength during follow-up. However, only the exercise group reduced carotid-femoral pulse wave velocity (-2.0 ± 0.6 m·s -1 , P = 0.048) and increased ( P < 0.05) resting oxygen saturation (1.9% ± 0.6%), mean inspiratory pressure (24.7 ± 7.1 cm H 2 O), mean expiratory pressure (20.3 ± 5.8 cm H 2 O), and percent of predicted mean expiratory pressure (14% ± 22%) during follow-up. No significant changes were found in any other variable during follow-up. CONCLUSIONS: Present findings suggest that tele-supervised home-based exercise training can be a potential adjunct therapeutic to rehabilitate individuals who were hospitalized due to COVID-19.

Association of physical activity and the risk of COVID-19 hospitalization: A dose-response meta-analysis.

BACKGROUND: Many people have experienced a high burden due to the spread of the coronavirus disease (COVID-19) and its serious consequences for health and everyday life. Prior studies have reported that physical activity (PA) may lower the risk of COVID-19 hospitalization. The present meta-analysis explored the dose-response relationship between PA and the risk of COVID-19 hospitalization. METHODS: Epidemiological observational studies on the relationship between PA and the risk of COVID-19 hospitalization were included. Categorical dose-response relationships between PA and the risk of COVID-19 hospitalization were assessed using random effect models. Robust error meta-regression models assessed the continuous relationship between PA (metabolic equivalent [Met]-h/wk) and COVID-19 hospitalization risk across studies reporting quantitative PA estimates. RESULTS: Seventeen observational studies (cohort\case-control\cross-section) met the criteria for inclusion in the meta-analysis. Categorical dose-relationship analysis showed a 40% (risk ratio [RR] 0.60, 95% confidence interval [CI]: 0.48-0.71) reduction in the risk of COVID-19 hospitalization compared to the lowest dose of PA. The results of the continuous dose-response relationship showed a non-linear inverse relationship (Pnon-linearity < .05) between PA and the risk of COVID-19 hospitalization. When total PA was < or >10 Met-h/wk, an increase of 4 Met-h/wk was associated with a 14% (RR = 0.83, 95% CI: 0.85-0.87) and 11% (RR = 0.89, 95% CI: 0.87-0.90) reduction in the risk of COVID-19 hospitalization, respectively. CONCLUSIONS: There was an inverse non-linear dose-response relationship between PA level and the risk of COVID-19 hospitalization. Doses of the guideline-recommended minimum PA levels by the World Health Organization may be required for more substantial reductions in the COVID-19 hospitalization risk.

Autonomic Function Recovery and Physical Activity Levels in Post-COVID-19 Young Adults after Immunization: An Observational Follow-Up Case-Control Study.

Coronavirus disease 2019 (COVID-19) has detrimental multi-system consequences. Symptoms may appear during the acute phase of infection, but the literature on long-term recovery of young adults after mild to moderate infection is lacking. Heart rate variability (HRV) allows for the observation of autonomic nervous system (ANS) modulation post-SARS-CoV-2 infection. Since physical activity (PA) can help improve ANS modulation, investigating factors that can influence HRV outcomes after COVID-19 is essential to advancements in care and intervention strategies. Clinicians may use this research to aid in the development of non-medication interventions. At baseline, 18 control (CT) and 20 post-COVID-19 (PCOV) participants were observed where general anamnesis was performed, followed by HRV and PA assessment. Thus, 10 CT and 7 PCOV subjects returned for follow-up (FU) evaluation 6 weeks after complete immunization (two doses) and assessments were repeated. Over the follow-up period, a decrease in sympathetic (SNS) activity (mean heart rate: p = 0.0024, CI = -24.67--3.26; SNS index: p = 0.0068, CI = -2.50--0.32) and increase in parasympathetic (PNS) activity (mean RR: p = 0.0097, CI = 33.72-225.51; PNS index: p = 0.0091, CI = -0.20-1.47) were observed. At follow-up, HRV was not different between groups (p > 0.05). Additionally, no differences were observed in PA between moments and groups. This study provides evidence of ANS recovery after SARS-CoV-2 insult in young adults over a follow-up period, independent of changes in PA.

Regional Difference in the Impact of COVID-19 Pandemic on Domain-Specific Physical Activity, Sedentary Behavior, Sleeping Time, and Step Count: Web-Based Cross-sectional Nationwide Survey and Accelerometer-Based Observational Study.

BACKGROUND: Physical activity (PA) and sedentary behavior (SB) have been affected by the COVID-19 pandemic and its restrictive environments, such as social distancing and lockdown measures. However, regional differences in the changes in domain-specific PA and SB in response to the COVID-19 pandemic are not clearly understood. OBJECTIVE: This study aimed to examine regional differences in domain-specific PA and SB, as well as sleeping time in response to the COVID-19 pandemic in Japan. METHODS: A web-based cross-sectional nationwide survey and an accelerometer-based longitudinal observation were conducted. In the web-based survey, we recruited 150 Japanese men and 150 Japanese women for each of the following age groups: 20s, 30s, 40s, 50s, 60s, and 70s (n=1800). A total of 1627 adults provided valid responses to web-based surveillance from June to July 2020. Participants were recruited from urban (Greater Tokyo Area, n=1028), urban-rural (regional core cities, n=459), or rural (regional small and medium cities, n=140) areas. They answered sociodemographic and health-related questions and retrospectively registered the PA data of their average day before and during the COVID-19 pandemic in a web-based PA record system. In the accelerometer-based observation, PA and step count data were obtained using a triaxial accelerometer on people living in urban (n=370) and rural (n=308) areas. RESULTS: Before the COVID-19 pandemic, there were no significant differences between these 3 regions in the time spent sleeping, staying at home, working or studying, and exercising (P>.05). By contrast, people living in urban areas had a longer duration of SB and transportation and a shorter duration of moderate-to-vigorous PA and lying or napping time compared with people living in rural areas (P>.05). During the COVID-19 pandemic, a significant decrease was observed in transportation time in urban (-7.2 min/day, P<.001) and urban-rural (-2.0 min/day, P=.009) areas but not in rural (-0.4 min/day, P=.52) areas. The moderate-to-vigorous PA was decreased in urban (-31.3 min/day, P<.001) and urban-rural (-30.0 min/day, P<.001) areas but not in rural areas (-17.3 min/day, P=.08). A significant increase was observed in time spent sleeping in urban (+22.4 min/day, P<.001) and urban-rural (+24.2 min/day, P<.001) but not in rural areas (+3.9 min/day, P=.74). Lying or napping was increased in urban (+14.9 min/day, P<.001) but not in rural areas (-6.9 min/day, P=.68). PA and step count obtained using an accelerometer significantly decreased in urban (P<.05) but not in rural areas (P>.05). CONCLUSIONS: The effect of the COVID-19 pandemic on PA and SB was significantly dependent on living area, even in a single country. The effects of PA and SB were greater in the Greater Tokyo Area and regional core cities but were not observed in regional small and medium cities in Japan.

National trends in physical activity among adolescents in South Korea before and during the COVID-19 pandemic, 2009-2021.

With the ongoing COVID-19 pandemic, several previous studies from different countries showed that physical activity (PA) decreased during the COVID-19 outbreak. However, few studies have examined the recent tendency of PA in the adolescent population. Thus, we aimed to investigate the long-term trend of PA in Korean youth and the prevalence changes between before and during the COVID-19 pandemic. Data from Korea Youth Risk Behavior Web-Based Survey (KYRBS) was collected for consecutive years between 2009 and 2021. The period was separated into prepandemic (2009-2019), early-pandemic (2020), and mid-pandemic (2021). Self-reported amount of PA was categorized into four groups (insufficient, aerobic, muscle strengthening, and both physical activities) according to World Health Organization (WHO) PA guidelines. A total of 840 488 adolescents aged 12-18 who fully responded to the survey were selected (response rate: 95.2%). The 13-year trends in the proportion of adolescents who reported aerobic and muscle-strengthening activities met or exceeded 2020 WHO exercise guidelines for adolescents plateaued (11.9% from 2009 to 2011, 14.2% from 2018 to 2019, 14.4% from 2020, and 14.0% from 2021); however, the slope decreased during the pandemic (ßdiff , -0.076; 95% confidence interval [CI], -0.123 to -0.029). Proportion of sufficient aerobic exercise among adolescents sharply decreased midst the pandemic (28.0% from 2009 to 2011, 29.4% from 2018 to 2019, and 23.8% from 2020; ßdiff , -0.266; 95% CI, -0.306 to -0.226) but increased again in 2021 (26.0% from mid-COVID 19; 95% CI, 25.4-26.7). Similar patterns were observed in Metabolic Equivalent Task (MET) score (MET-min/week; 804.1 from 2018 to 2019, 720.9 from 2020, and 779.6 from 2021). The mean difference in MET score between pre-COVID and post-COVID was -55.4 MET-min/week (95% CI, -70.5 to -40.3). Through a nationwide representative study, there was no significant difference with regard to the number of Korean adolescents who achieved the PA guidelines (pre and postpandemic); however, the prevalence of recommended levels of PA needs to increase more based on the trend before the COVID-19 outbreak. The findings of this study suggest reinforcement of the importance of public health policies for Korean youths to be more physically active, especially during and after the pandemic.