Does Higher Self-Reported Cardiorespiratory Fitness Reduce the Odds of Hospitalization From COVID-19?

Physiological presentation and risk factors of long COVID in the UK using smartphones and wearable devices: a longitudinal, citizen science, case-control study

BACKGROUND

The emergence of long COVID as a COVID-19 sequela was largely syndromic in characterisation. Digital health technologies such as wearable devices open the possibility to study this condition with passive, objective data in addition to self-reported symptoms. We aimed to quantify the prevalence and severity of symptoms across collected mobile health metrics over 12 weeks following COVID-19 diagnosis and to identify risk factors for the development of post-COVID-19 condition (also known as long COVID).

METHODS

The Covid Collab study was a longitudinal, self-enrolled, community, case-control study. We recruited participants from the UK through a smartphone app, media publications, and promotion within the Fitbit app between Aug 28, 2020, and May 31, 2021. Adults (aged ≥18 years) who reported a COVID-19 diagnosis with a positive antigen or PCR test before Feb 1, 2022, were eligible for inclusion. We compared a cohort of 1200 patients who tested positive for COVID-19 with a cohort of 3600 sex-matched and age-matched controls without a COVID-19 diagnosis. Participants could provide information on COVID-19 symptoms and mental health through self-reported questionnaires (active data) and commercial wearable fitness devices (passive data). Data were compared between cohorts at three periods following diagnosis: acute COVID-19 (0-4 weeks), ongoing COVID-19 (4-12 weeks), and post-COVID-19 (12-16 weeks). We assessed sociodemographic and mobile health risk factors for the development of long COVID (defined as either a persistent change in a physiological signal or self-reported symptoms for ≥12 weeks after COVID-19 diagnosis).

FINDINGS

By Aug 1, 2022, 17 667 participants had enrolled into the study, of whom 1200 (6·8%) cases and 3600 (20·4%) controls were included in the analyses. Compared with baseline (65 beats per min), resting heart rate increased significantly during the acute (0·47 beats per min; odds ratio [OR] 1·06 [95% CI 1·03-1·09]; p<0·0001), ongoing (0·99 beats per min; 1·11 [1·08-1·14]; p<0·0001), and post-COVID-19 (0·52 beats per min; 1·04 [1·02-1·07]; p=0·0017) phases. An increased level of historical activity in the period from 24 months to 6 months preceding COVID-19 diagnosis was protective against long COVID (coefficient -0·017 [95% CI -0·030 to -0·003]; p=0·015). Depressive symptoms were persistently elevated following COVID-19 (OR 1·03 [95% CI 1·01-1·06]; p=0·0033) and were a potential risk factor for developing long COVID (1·14 [1·07-1·22]; p<0·0001).

INTERPRETATION

Mobile health technologies and commercial wearable devices might prove to be a useful resource for tracking recovery from COVID-19 and the prevalence of its long-term sequelae, as well as representing an abundant source of historical data. Mental wellbeing can be impacted negatively for an extended period following COVID-19.

FUNDING

National Institute for Health and Care Research (NIHR), NIHR Maudsley Biomedical Research Centre, UK Research and Innovation, and Medical Research Council.

Effects of Exercise Rehabilitation on Cardiorespiratory Fitness in Long-COVID-19 Survivors: A Meta-Analysis

Background: Poor cardiorespiratory fitness poses the highest risk of mortality. Long-COVID-19 survivors exhibit a reduced cardiorespiratory fitness (CRF). While exercise rehabilitation, such as cardiopulmonary exercise, is used for long-COVID-19 survivors, the effects of exercise on CRF in this population remain inconclusive. In this study, we aim to systematically summarise and synthesise whether exercise rehabilitation improves CRF among long-COVID-19 survivors. Methods: A comprehensive search was performed through PubMed, CINAHL, Embase, Scopus, and the Cochrane Library (since their inception to November 2023) and study reference lists. Studies presenting the effects of exercise rehabilitation on CRF (peak oxygen consumption (VO2peak) and six-minute walk distance (6MWD)) in long-COVID-19 survivors were identified. The standardised mean difference (SMD), mean difference (MD), and 95% confidence interval (CI) were used for analyses. The certainty of evidence was measured using a Grading of Recommendation Assessment, Development and Evaluation approach. Results: Twelve eligible studies (five RCTs and seven non-RCTs) with 682 participants were analysed. The meta-analysis showed significantly improved 6MWDs (MD 76.47, 95% CI 59.19-93.71, low certainty) and significantly greater 6MWDs (SMD 0.85, 95% CI 0.11-1.59, very low certainty) in the exercise rehabilitation group compared to the control group. A significantly improved 6MWD was found in subgroups of young to middle-aged adults and subgroups of patients who undertook aerobic exercise combined with resistance and respiratory exercise and centre-based training programs. Conclusions: Exercise rehabilitation is effective for improving CRF, as measured by the 6MWD in long-COVID-19 survivors. Improvements are likely to be more pronounced in specific subgroups of young to middle-aged adults and patients undertaking aerobic exercise combined with resistance and respiratory exercise and centre-based training programs. However, recommendations for clinical practice are limited due to the very low evidence certainty.

Insights from Chilean NCDs Hospitalization Data during COVID-19

The COVID-19 pandemic has affected the lifestyles of people of all ages, conditions and occupations. Social distance, remote working, changes in diet and a lack of physical activity have directly and indirectly affected many aspects of mental and physical health, particularly in patients with many comorbidities and non-communicable diseases (NCDs). In our paper, we analyzed COVID-19 hospitalized and non-hospitalized cases according to comorbidities to assess the average monthly percentage change (AMPC) and monthly percentage change (MPC) using open access data from the Chilean Ministry of Science, Technology, Knowledge and Innovation. As expected, the infection mainly affected patients with comorbidities, including cardiovascular risk factors. The hospitalized cases with obesity and chronic lung disease increased throughout the period of June 2020-August 2021 (AMPC = ↑20.8 and ↑19.4%, respectively, p < 0.05), as did all the non-hospitalized cases with comorbidities throughout the period (AMPC = ↑15.6 to ↑30.3 [p < 0.05]). The increases in hospitalizations and non-hospitalizations with comorbidities may be associated with physical inactivity. A healthy lifestyle with regular physical activity may have had a protective effect on the COVID-19 severity and related events in the post-pandemic period, especially for the NCD population.

The Role of Diet and Physical Activity in Shaping COVID-19 Severity: Design, Validation, and Application of a Retrospective Questionnaire

After the global challenges posed by COVID-19, researchers strived to identify risk factors for severe cases, which lead to various complications-including death. Lifestyle modifications, such as implementing a healthy diet and recommended physical activity, have been shown to be protective against severe COVID-19 cases. Despite an association of a plant-based diet with reduced COVID-19 severity, specific dietary characteristics have not been identified. Also, the methodology for measuring physical activity is variable, with studies overlooking the intensity or the habit components of physical activity. To bridge this gap, our study designed, validated, and applied a retrospective questionnaire with aims of exploring the relationship between lifestyle factors, specifically diet and physical activity, and severe COVID-19. We considered the intensity and years of physical activity habit, which is a limitation of other questionnaires. Results reveal associations of age and BMI with severe COVID-19. An excessive sugar diet was found to be associated with severe COVID-19 and increased symptom duration. We also observed an inverse relationship pattern of moderate- and vigorous-intensity physical activity across case severity, which is absent in walking physical activity. This study lays a foundation for research aiming to identify lifestyle factors that prevent severe COVID-19 cases.

Being fit in the COVID-19 era and future epidemics prevention: Importance of cardiopulmonary exercise test in fitness evaluation

Endurance and resistance physical activity have been shown to stimulate the production of immunoglobulins and boost the levels of anti-inflammatory cytokines, natural killer cells, and neutrophils in the bloodstream, thereby strengthening the ability of the innate immune system to protect against diseases and infections. Coronavirus disease 19 (COVID-19) greatly impacted people's cardiorespiratory fitness (CRF) and health worldwide. Cardiopulmonary exercise testing (CPET) remains valuable in assessing physical condition, predicting illness severity, and guiding interventions and treatments. In this narrative review, we summarize the connections and impact of COVID-19 on CRF levels and its implications on the disease's progression, prognosis, and mortality. We also emphasize the significant contribution of CPET in both clinical evaluations of recovering COVID-19 patients and scientific investigations focused on comprehending the enduring health consequences of SARS-CoV-2 infection.

Prepandemic Physical Activity and Risk of COVID-19 Diagnosis and Hospitalization in Older Adults

Importance

Higher prepandemic physical activity (PA) levels have been associated with lower risk and severity of COVID-19.

Objective

To investigate the association between self-reported prepandemic PA levels and the risk and severity of COVID-19 in older US adults.

Design, Setting, and Participants

This cohort study combined cohorts from 3 ongoing prospective randomized clinical trials of US adults aged 45 years or older who provided prepandemic self-reports of baseline leisure-time PA and risk factors for COVID-19 outcomes using the most recent questionnaire completed as of December 31, 2019, as the baseline PA assessment. In multiple surveys from May 2020 through May 2022, participants indicated whether they had at least 1 positive COVID-19 test result or were diagnosed with or hospitalized for COVID-19.

Exposure

Prepandemic PA, categorized into 3 groups by metabolic equivalent hours per week: inactive (0-3.5), insufficiently active (>3.5 to <7.5), and sufficiently active (≥7.5).

Main Outcome and Measures

Primary outcomes were risk of COVID-19 and hospitalization for COVID-19. Multivariable logistic regression was used to estimate odd ratios (ORs) and 95% CIs for the association of COVID-19 diagnosis and/or hospitalization with each of the 2 upper PA categories vs the lowest PA category.

Results

The pooled cohort included 61 557 participants (mean [SD] age, 75.7 [6.4] years; 70.7% female), 20.2% of whom were inactive; 11.4%, insufficiently active; and 68.5%, sufficiently active. A total of 5890 confirmed incident cases of COVID-19 were reported through May 2022, including 626 hospitalizations. After controlling for demographics, body mass index, lifestyle factors, comorbidities, and medications used, compared with inactive individuals, those insufficiently active had no significant reduction in infection (OR, 0.96; 95% CI, 0.86-1.06) or hospitalization (OR, 0.98; 95% CI, 0.76-1.28), whereas those sufficiently active had a significant reduction in infection (OR, 0.90; 95% CI, 0.84-0.97) and hospitalization (OR, 0.73; 95% CI, 0.60-0.90). In subgroup analyses, the association between PA and SARS-CoV-2 infection differed by sex, with only sufficiently active women having decreased odds (OR, 0.87; 95% CI, 0.79-0.95; P = .04 for interaction).

Conclusions and Relevance

In this cohort study of adults aged 45 years or older, those who adhered to PA guidelines before the pandemic had lower odds of developing or being hospitalized for COVID-19. Thus, higher prepandemic PA levels may be associated with reduced odds of SARS-CoV-2 infection and hospitalization for COVID-19.

Physical fitness level and the risk of severe COVID-19: A systematic review

To verify systematically the association between the status of physical fitness and the risk of severe Coronavirus disease 2019 (COVID-19). This systematic review is in accordance with the Preferred Reporting Items for Systematic Review and Meta Analyses (PRISMA) statement and the eligibility criteria followed the Population, Intervention, Comparison, Outcomes and Study (PICOS) recommendation. PubMed, Embase, SciELO and Cochrane electronic databases were searched. All studies that explored the relationship between the pattern of physical fitness and COVID-19 adverse outcomes (hospitalization, intensive care unit admission, intubation, or mortality), were selected. The quality of the studies was assessed by the specific scale of the Newcastle-Ottawa Scale. A total of seven observational studies were identified in this systematic review; 13 ​468 patients were included in one case-control study, two cohort studies, and four cross-sectional studies. All studies reported an inverse association between high physical fitness and severe COVID-19 (hospitalization, intensive care admission, or mortality). Only some studies reported comorbidities, especially obesity and cardiovascular disorders, but the results remained unchanged after controlling for comorbidities. The quality of the seven studies included was moderate according to the Newcastle-Ottawa Quality Assessment Scale. The methodological heterogeneity of the studies included did not allow a meta-analysis of the findings. In conclusion, higher physical fitness levels were associated with lower risk of hospitalization, intensive care admissions, and mortality rates among patients with COVID-19.

COVID-19: Insights into long-term manifestations and lockdown impacts

Coronaviruses are pathogens thought to primarily affect the respiratory tracts of humans. The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019 was also marked mainly by its symptoms of respiratory illness, which were named coronavirus disease 2019 (COVID-19). Since its initial discovery, many other symptoms have been linked to acute SARS-CoV-2 infections as well as to the long-term outcomes of COVID-19 patients. Among these symptoms are different categories of cardiovascular diseases (CVDs), which continue to be the main cause of death worldwide. The World Health Organization estimates that 17.9 million people die from CVDs each year, accounting for ∼32% of all deaths globally. Physical inactivity is one of the most important behavioral risk factors for CVDs. The COVID-19 pandemic has affected CVDs as well as the physical activity in different ways. Here, we provide an overview of the current status as well as future challenges and possible solutions.

Baseline physical activity and the risk of severe illness and mortality from COVID-19: A dose-response meta-analysis

To provide a scientific basis for improved exercise-based immunity, a meta-analysis was used to explore the dose-response relationship between physical activity (PA) and the risk of severe illness and mortality related to COVID-19 (coronavirus disease 2019). To this end, we searched PubMed, Web of Science databases from January 2020 through April 2022. 14 observational studies met the criteria for inclusion in the meta-analysis, including 2840 cases of severe illness and death from COVID-19. Categorical dose-relationship analysis showed that the risks of severe illness and mortality from COVID-19 were, respectively, 46% (risk ratio (RR): 0.54; confidence intervals (CIs): 0.41-0.68) and 59% (RR = 0.41; 95%CI: 0.23-0.58) lower for the highest dose of PA compared with the lowest dose of PA. The results of the continuous dose-response analysis show an inverse nonlinear relationship (P_{non-linearity} < 0.05) between PA and both the risk of severe illness and mortality from COVID-19. For PA below 10 MET-h/week (MET-h/week: metabolic equivalent of task-hours/week), an increase of 4 MET-h/week (1 h of moderate-intensity or 0.5 h of high-intensity PA) was associated with 8% and 11% reductions in the risk of severe illness and mortality from COVID-19. PA above 10 MET-h/week lowered the risk of severe illness and mortality from COVID-19 by 7% and 9%, respectively, for each 4 MET-h/week increase. Doses of WHO-recommended PA levels (10 MET-h/week) may be required for more substantial reductions in the risk of severe illness and mortality from 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.

The role of physical activity in the clinical outcomes of people diagnosed with Covid-19: A systematic review

Objective

This review aimed to compile the evidence on PA and clinical outcomes of people receiving a positive diagnosis of covid-19.

Design

Systematic review.

Methods

The search was performed in five databases: EMBASE, MEDLINE via PubMed portal, Scopus, SPORTDiscus via EBSCO platform, and Web of Science. In addition, the "gray" literature was searched through Google Scholar and medRxiv published between January 2020 and July 2022. Studies were assessed for risk of bias, with the extraction of relevant data. Our search revealed a total of 10,028 studies.

Results

After applying the eligibility criteria 32 studies were included. Thirty-one studies were at low to moderate risk of bias. Physically active individuals, who were diagnosed with covid-19, presented attenuation of clinical outcomes, such as decreased risk of hospitalization, recovery time, number of symptoms, severity, and ICU and death when compared to individuals with low levels of PA or classified as sedentary.

Conclusions

Physically active individuals when diagnosed with covid-19 may have decreased risk of several clinical outcomes related to covid-19, including but not limited to hospitalization and number of symptoms. Public health authorities should develop strategies and initiatives that promote safe PA environments to improve the clinical prognosis of people diagnosed with covid-19.

Study registration

Open Science Framework (OSF), DOI registry 10.17605/OSF.IO/PV6NF. It can be consulted through the access link: https://doi.org/10.17605/OSF.IO/PV6NF, October 07, 2021.

Body composition and cardiorespiratory fitness in overweight or obese people post COVID-19: A comparative study

The present study aimed to evaluate the body composition and cardiorespiratory fitness of overweight or obese people after COVID-19. 171 volunteers of both sexes (men, n = 93 and women, n = 78) between 19 and 65 years old were allocated into three groups according to the severity of their symptoms of COVID-19: non-hospitalized people/mild symptoms (n = 61), hospitalized (n = 58), and hospitalized in an intensive care unit-ICU (n = 52). Two laboratory visits were carried out 24 h apart. First, a medical consultation was carried out, with subsequent measurement of body weight and height (calculation of body mass index) and body composition assessment via electrical bioimpedance. After 24 h, a cardiorespiratory test was performed using the Bruce protocol, with a direct gas exchange analysis. Hospitalized individuals had significantly higher values for fat mass and body fat percentage than non-hospitalized individuals (p < 0.05). Significantly higher values were found for heart rate (HR) and peak oxygen consumption (VO₂peak) for individuals who were not hospitalized when compared to those hospitalized in the ICU (p < 0.05). Significantly higher values for distance, ventilation, and the relationship between respiratory quotient were found for non-hospitalized individuals compared to hospitalized individuals and those in the ICU (p < 0.05). After the cardiorespiratory test, higher values for peripheral oxygen saturation (SpO₂) were observed for non-hospitalized individuals than for all hospitalized individuals (p < 0.05). Diastolic blood pressure was significantly higher at the tenth and fifteenth minute post-Bruce test in hospitalized than in non-hospitalized participants (p < 0.05). Based on these results, proposals for cardiopulmonary rehabilitation are indispensable for hospitalized groups considering the responses of blood pressure. Monitoring HR, SpO_2, and blood pressure are necessary during rehabilitation to avoid possible physical complications. Volume and intensity of exercise prescription should respect the physiologic adaptation. Given lower physical conditioning among all the groups, proposals for recovering from health conditions are urgent and indispensable for COVID-19 survivors.

Physical activity and risk of infection, severity and mortality of COVID-19: a systematic review and non-linear dose-response meta-analysis of data from 1 853 610 adults

OBJECTIVE

To quantify the association between physical activity and risk of SARS-CoV-2 infection, COVID-19-associated hospitalisation, severe illness and death due to COVID-19 in adults.

DESIGN

A systematic review and meta-analysis.

DATA SOURCES

Three databases were systematically searched through March 2022.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Peer-reviewed articles reporting the association between regular physical activity and at least one COVID-19 outcome in adults were included. Risk estimates (ORs, relative risk (RR) ratios or HRs) were extracted and pooled using a random-effects inverse-variance model.

RESULTS

Sixteen studies were included (n=1 853 610). Overall, those who engaged in regular physical activity had a lower risk of infection (RR=0.89; 95% CI 0.84 to 0.95; I2=0%), hospitalisation (RR=0.64; 95% CI 0.54 to 0.76; I2=48.01%), severe COVID-19 illness (RR=0.66; 95% CI 0.58 to 0.77; I2=50.93%) and COVID-19-related death (RR=0.57; 95% CI 0.46 to 0.71; I2=26.63%) as compared with their inactive peers. The results indicated a non-linear dose-response relationship between physical activity presented in metabolic equivalent of task (MET)-min per week and severe COVID-19 illness and death (p for non-linearity <0.001) with a flattening of the dose-response curve at around 500 MET-min per week.

CONCLUSIONS

Regular physical activity seems to be related to a lower likelihood of adverse COVID-19 outcomes. Our findings highlight the protective effects of engaging in sufficient physical activity as a public health strategy, with potential benefits to reduce the risk of severe COVID-19. Given the heterogeneity and risk of publication bias, further studies with standardised methodology and outcome reporting are now needed.

PROSPERO REGISTRATION NUMBER

CRD42022313629.

Estimated Oxygen Consumption with the Abbreviated Method and Its Association with Vaccination and PCR Tests for COVID-19 from Socio-Demographic, Anthropometric, Lifestyle, and Morbidity Outcomes in Chilean Adults

COVID-19 causes cardiovascular and lung problems that can be aggravated by confinement, but the practice of physical activity (PA) could lessen these effects. The objective of this study was to evaluate the association of maximum oxygen consumption (V˙O2max) with vaccination and PCR tests in apparently healthy Chilean adults. An observational and cross-sectional study was performed, in which 557 people from south-central Chile participated, who answered an online questionnaire on the control of COVID-19, demographic data, lifestyles, and diagnosis of non-communicable diseases. V˙O2max was estimated with an abbreviated method. With respect to the unvaccinated, those who received the first (OR:0.52 [CI:0.29;0.95], p = 0.019) and second vaccine (OR:0.33 [CI:0.18;0.59], p = 0.0001) were less likely to have an increased V˙O2max. The first vaccine was inversely associated with V˙O2max (mL/kg/min) (β:−1.68 [CI:−3.06; −0.3], p = 0.017), adjusted for BMI (β:−1.37 [CI:−2.71; −0.03], p = 0.044) and by demographic variables (β:−1.82 [CI:−3.18; −0.46], p = 0.009); similarly occur for the second vaccine (β: between −2.54 and −3.44, p < 0.001) on models with and without adjustment. Having taken a PCR test was not significantly associated with V˙O2max (mL/kg/min). It is concluded that vaccination significantly decreased V˙O2max, although it did not indicate cause and effect. There is little evidence of this interaction, although the results suggest an association, since V˙ O2max could prevent and attenuate the contagion symptoms and effects.

Small steps, strong shield: directly measured, moderate physical activity in 65 361 adults is associated with significant protective effects from severe COVID-19 outcomes

Objective

To determine the association between directly measured physical activity and hospitalisation, intensive care unit (ICU) admission, ventilation and mortality rates in patients with a confirmed diagnosis of COVID-19.

Methods

Directly measured physical activity data from 65 361 adult patients with a COVID-19 diagnosis from 19 March 2020 to 30 June 2021, were grouped by activity level: low (<60 min/week), moderate (60–149 min/week) and high activity (≥150 min/week). The association of physical activity levels and the risk of adverse outcomes was analysed using modified Poisson regression. We accounted for demographics and comorbidities including conditions known to influence COVID-19 outcomes, as well as patient complexity as measured by the Johns Hopkins Adjusted Clinical Group system. The regression approach was further validated with a Bayesian network model built off a directed acyclic graph.

Results

High physical activity was associated with lower rates of hospitalisation (risk ratio, RR 0.66, 95% CI 0.63 to 0.70), ICU admission (RR 0.59, 95% CI 0.52 to 0.66), ventilation (RR 0.55, 95% CI 0.47 to 0.64) and death (RR 0.58, 95% CI 0.50 to 0.68) due to COVID-19 than those who engaged in low physical activity. Moderate physical activity also was associated with lower rates of hospitalisation (RR 0.87, 95% CI 0.82 to 0.91), admission to ICU (RR 0.80, 95% CI 0.71 to 0.89), ventilation (RR 0.73, 95% CI 0.62 to 0.84) and death (RR 0.79, 95% CI 0.69 to 0.91).

Conclusions

Adults with high and moderate physical activity levels had significantly better outcomes than those with low activity when contracting COVID-19. The apparent protective effects of regular physical activity extended to those with concomitant chronic medical conditions.

Protocol for a systematic review and meta-analysis of observational studies examining the impact of COVID-19 safety measures on physical activity patterns in adults

BACKGROUND

The primary objective of this study is twofold: (1) to examine the effect of COVID-19 safety measures, enacted to prevent transmission of SARS-nCOV-2, on total physical activity in the adult general population (≥ 18 years) and (2) to analyze the impact of the factor "severity of safety measures" on potential changes in physical activity. The secondary objective is to investigate the effects of safety measures on the respective PA intensities, i.e., sedentary behavior, light, moderate, and vigorous physical activity.

METHODS

A systematic literature search will be performed in the following online databases: Medline (on Ovid), Web of Science, Scopus, L^.OVE Coronavirus disease by Epistemonikos, and ProQuest Dissertations & Theses A&I. All obtained citations will undergo title and abstract as well as full-text screening by two independent reviewers. Observational studies investigating the effects of safety measures on physical activity patterns in the adult general population will be included. The standardized mean difference in total physical activity per time unit between pre- and during COVID-19 or between normative data and during COVID-19 will be the primary outcome. The standardized mean difference in sedentary time, light, moderate, and vigorous physical activity will be assessed as secondary outcomes. Eligible studies will be divided between the reviewers for data extraction using a pilot-tested data form. Risk of bias assessment will be performed using a standard assessment tool. If suitable, a random-effects meta-analysis and meta-regression with a unit of safety measure severity as the independent variable will be performed.

DISCUSSION

This study will synthesize available data reporting the effect of COVID-19 safety measures on physical activity patterns in adults. Furthermore, we will incorporate a unit for the severity of safety measures for better generalizability of the results. These findings will be of great value for public health policymaking and estimating future health consequences.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021231039.

Covid-19 and the next outbreak: decreasing frailty by using mild stress?

The coronavirus disease 2019 (Covid-19) has resulted in many deaths, particularly of very old or obese people. These people are at risk to die in the event of an outbreak, like under one-year old babies were at risk to die one century ago from various diseases. It is argued that mild stress could help people to resist new outbreaks. The people who are obese because of bad feeding habits (snacking, junk food, overfeeding) and inactivity should adopt more healthy behaviours. Because an inactive way of life at old age can increase frailty, physical and mental activities should be kept at the highest possible level in elderly people, particularly if they live in retirement homes. In the event of an outbreak, management staff of these homes should not confine residents in their room for weeks or months, as it can increase inactivity, under-nutrition, sarcopenia, and depressive symptoms. People with or without co-morbidities should be active and one could wonder whether other mild stresses such as sauna bathing could help to better resist infection.