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Exercise for COVID-19: real-time meta analysis of 33 studies
Covid Analysis, May 22, 2022, DRAFT
https://c19early.com/exmeta.html
0 0.5 1 1.5+ All studies 39% 33 809,459 Improvement, Studies, Patients Relative Risk Mortality 44% 12 782,756 Ventilation 46% 2 43,773 ICU admission 41% 2 52,937 Hospitalization 42% 7 11,181 Recovery 57% 2 66 Cases 20% 14 77,841 Peer-reviewed 39% 32 809,459 Prophylaxis 39% 33 809,459 Exercise for COVID-19 c19early.com/ex May 2022 Favorsexercise Favorsinactivity after exclusions
Statistically significant improvements are seen for mortality, ventilation, ICU admission, hospitalization, recovery, and cases. 26 studies from 26 independent teams in 14 different countries show statistically significant improvements in isolation (19 for the most serious outcome).
Meta analysis using the most serious outcome reported shows 39% [31‑46%] improvement. Results are similar after exclusions and similar for peer-reviewed studies.
Results are robust — in exclusion sensitivity analysis 28 of 33 studies must be excluded to avoid finding statistically significant efficacy in pooled analysis.
Results are consistent with the overall risk of all cause mortality based on cardiorespiratory fitness — [Laukkanen] show RR 0.55 [0.50-0.61] for the top vs. bottom tertiles.
0 0.5 1 1.5+ All studies 39% 33 809,459 Improvement, Studies, Patients Relative Risk Mortality 44% 12 782,756 Ventilation 46% 2 43,773 ICU admission 41% 2 52,937 Hospitalization 42% 7 11,181 Recovery 57% 2 66 Cases 20% 14 77,841 Peer-reviewed 39% 32 809,459 Prophylaxis 39% 33 809,459 Exercise for COVID-19 c19early.com/ex May 2022 Favorsexercise Favorsinactivity after exclusions
Studies analyze exercise/physical activity levels before infection, comparing regular/moderate exercise vs. lower/no exercise. Note that risk may increase with more extreme activity levels.
No treatment, vaccine, or intervention is 100% available and effective for all variants. All practical, effective, and safe means should be used. Denying the efficacy of treatments increases mortality, morbidity, collateral damage, and endemic risk.
All data to reproduce this paper and sources are in the appendix. [Rahmati] present another meta analysis for exercise, showing significant improvements for mortality, ICU admission, and hospitalization.
Highlights
Exercise reduces risk for COVID-19 with very high confidence for mortality, ventilation, ICU admission, hospitalization, recovery, cases, and in pooled analysis.
We show traditional outcome specific analyses and combined evidence from all studies.
Real-time updates and corrections, transparent analysis with all results in the same format, consistent protocol for 42 treatments.
A
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Hamer 28% 0.72 [0.61-0.87] hosp. n/a n/a Improvement, RR [CI] Treatment Control Brawner 74% 0.26 [0.11-0.58] hosp. n/a n/a Zhang 26% 0.74 [0.48-1.14] death n/a n/a Tavakol 69% 0.31 [0.10-1.02] severe case 3/64 19/124 Yates 45% 0.55 [0.38-0.79] death 72/163,912 62/30,119 Holt 17% 0.83 [0.63-1.09] cases n/a n/a Cho 53% 0.47 [0.26-0.87] death case control Sallis 59% 0.41 [0.22-0.76] death 11/3,118 170/6,984 Christensen 63% 0.37 [0.16-0.85] death 543 (n) 529 (n) Latorre-Román 76% 0.24 [0.05-1.04] hosp. n/a n/a Marcus 42% 0.58 [0.48-0.71] symp. case 240/10,627 134/3,708 Yuan 91% 0.09 [0.01-1.65] death 0/61 6/103 Brandenburg -6% 1.06 [0.23-4.79] hosp. 102 (n) 39 (n) Bielik 30% 0.70 [0.40-1.21] mod. case 775 (n) 365 (n) Lee 74% 0.26 [0.07-0.99] death 2/11,072 32/41,293 Maltagliati 52% 0.48 [0.25-0.87] hosp. n/a n/a Baynouna AlKetbi 98% 0.01 [0.00-0.44] death n/a n/a Ahmadi 30% 0.70 [0.54-0.89] death 160/232,613 112/95,221 Nguyen 20% 0.80 [0.72-0.88] symp. case 904/2,836 483/1,111 Lin 47% 0.53 [0.12-2.33] cases n/a n/a de Souza 73% 0.27 [0.07-1.06] ventilation 3/611 6/327 Mohsin 19% 0.81 [0.66-0.99] severe case 86/258 224/544 Ekblom-Bak 48% 0.52 [0.30-0.92] severe case n/a n/a Lengelé 74% 0.26 [0.07-0.80] cases 23/229 4/12 Saadeh 9% 0.91 [0.56-1.43] symp. case 362 (n) 225 (n) Hamrouni 29% 0.71 [0.55-0.92] death 138/106,006 109/47,827 Huang 47% 0.53 [0.23-1.22] severe case 7/74 16/90 Steenkamp 42% 0.58 [0.50-0.68] death 29,469 (n) 13,366 (n) Gilley -42% 1.42 [0.60-3.35] cases 172/1,917 5/79 Beydoun 43% 0.57 [0.32-1.01] cases 1,710 (n) 448 (n) Salgado-Aranda 83% 0.17 [0.05-0.56] death 4/223 41/297 Paul 38% 0.62 [0.30-1.20] no recov. n/a n/a Kontopoulou 66% 0.34 [0.24-0.47] recov. time 42 (n) 24 (n) Tau​2 = 0.06, I​2 = 68.8%, p < 0.0001 Prophylaxis 39% 0.61 [0.54-0.69] 1,825/566,624 1,423/242,835 39% improvement All studies 39% 0.61 [0.54-0.69] 1,825/566,624 1,423/242,835 39% improvement 33 exercise COVID-19 studies c19early.com/ex May 2022 Tau​2 = 0.06, I​2 = 68.8%, p < 0.0001 Effect extraction pre-specified(most serious outcome, see appendix) Favors exercise Favors inactivity
Figure 1. A. Random effects meta-analysis. This plot shows pooled effects, discussion can be found in the heterogeneity section, and results for specific outcomes can be found in the individual outcome analyses. Effect extraction is pre-specified, using the most serious outcome reported. For details of effect extraction see the appendix. B. Scatter plot showing the distribution of effects reported in studies. C. History of all reported effects (chronological within treatment stages).
Introduction
We analyze all significant studies reporting COVID-19 outcomes as a function of physical activity levels. Search methods, inclusion criteria, effect extraction criteria (more serious outcomes have priority), all individual study data, PRISMA answers, and statistical methods are detailed in Appendix 1. We present random effects meta-analysis results for all studies, for studies within each treatment stage, for individual outcomes, for peer-reviewed studies, for Randomized Controlled Trials (RCTs), and after exclusions.
Physical Inactivity
Insufficient physical activity is a risk factor for many diseases and is common around the world [Guthold], as shown in Figure 2. [Guthold] found that prevalence in high-income countries was over twice as high, and has increased over time.
Figure 2. Prevalence of insufficient physical activity around the world as of 2016, from [Guthold] (top: female, bottom: male).
For upper respiratory tract infections, research shows lower risk for moderate activity vs. a sedentary lifestyle, however risk increases with more extreme activity levels [Nieman].
Figure 2. Risk may increase with more extreme activity levels, as seen with upper respiratory tract infections [Nieman].
Results
Figure 3 shows a visual overview of the results, with details in Table 1 and Table 2. Figure 4, 5, 6, 7, 8, 9, 10, and 11 show forest plots for a random effects meta-analysis of all studies with pooled effects, mortality results, ventilation, ICU admission, hospitalization, recovery, cases, and peer reviewed studies.
0 0.5 1 1.5+ ALL STUDIES MORTALITY VENTILATION ICU ADMISSION HOSPITALIZATION RECOVERY CASES PEER-REVIEWED After Exclusions ALL STUDIES All Prophylaxis Exercise for COVID-19 C19EARLY.COM/EX MAY 2022
Figure 3. Overview of results.
Treatment timeNumber of studies reporting positive effects Total number of studiesPercentage of studies reporting positive effects Random effects meta-analysis results
Prophylaxis 31 33 93.9% 39% improvement
RR 0.61 [0.54‑0.69]
p < 0.0001
All studies 31 33 93.9% 39% improvement
RR 0.61 [0.54‑0.69]
p < 0.0001
Table 1. Results by treatment stage.
Studies Prophylaxis PatientsAuthors
All studies 3339% [31‑46%] 809,459 334
With exclusions 3037% [29‑44%] 808,427 310
Peer-reviewed 3239% [31‑46%] 809,459 332
Table 2. Results by treatment stage for all studies and with different exclusions.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Hamer 28% 0.72 [0.61-0.87] hosp. n/a n/a Improvement, RR [CI] Treatment Control Brawner 74% 0.26 [0.11-0.58] hosp. n/a n/a Zhang 26% 0.74 [0.48-1.14] death n/a n/a Tavakol 69% 0.31 [0.10-1.02] severe case 3/64 19/124 Yates 45% 0.55 [0.38-0.79] death 72/163,912 62/30,119 Holt 17% 0.83 [0.63-1.09] cases n/a n/a Cho 53% 0.47 [0.26-0.87] death case control Sallis 59% 0.41 [0.22-0.76] death 11/3,118 170/6,984 Christensen 63% 0.37 [0.16-0.85] death 543 (n) 529 (n) Latorre-Román 76% 0.24 [0.05-1.04] hosp. n/a n/a Marcus 42% 0.58 [0.48-0.71] symp. case 240/10,627 134/3,708 Yuan 91% 0.09 [0.01-1.65] death 0/61 6/103 Brandenburg -6% 1.06 [0.23-4.79] hosp. 102 (n) 39 (n) Bielik 30% 0.70 [0.40-1.21] mod. case 775 (n) 365 (n) Lee 74% 0.26 [0.07-0.99] death 2/11,072 32/41,293 Maltagliati 52% 0.48 [0.25-0.87] hosp. n/a n/a Baynouna AlKetbi 98% 0.01 [0.00-0.44] death n/a n/a Ahmadi 30% 0.70 [0.54-0.89] death 160/232,613 112/95,221 Nguyen 20% 0.80 [0.72-0.88] symp. case 904/2,836 483/1,111 Lin 47% 0.53 [0.12-2.33] cases n/a n/a de Souza 73% 0.27 [0.07-1.06] ventilation 3/611 6/327 Mohsin 19% 0.81 [0.66-0.99] severe case 86/258 224/544 Ekblom-Bak 48% 0.52 [0.30-0.92] severe case n/a n/a Lengelé 74% 0.26 [0.07-0.80] cases 23/229 4/12 Saadeh 9% 0.91 [0.56-1.43] symp. case 362 (n) 225 (n) Hamrouni 29% 0.71 [0.55-0.92] death 138/106,006 109/47,827 Huang 47% 0.53 [0.23-1.22] severe case 7/74 16/90 Steenkamp 42% 0.58 [0.50-0.68] death 29,469 (n) 13,366 (n) Gilley -42% 1.42 [0.60-3.35] cases 172/1,917 5/79 Beydoun 43% 0.57 [0.32-1.01] cases 1,710 (n) 448 (n) Salgado-Aranda 83% 0.17 [0.05-0.56] death 4/223 41/297 Paul 38% 0.62 [0.30-1.20] no recov. n/a n/a Kontopoulou 66% 0.34 [0.24-0.47] recov. time 42 (n) 24 (n) Tau​2 = 0.06, I​2 = 68.8%, p < 0.0001 Prophylaxis 39% 0.61 [0.54-0.69] 1,825/566,624 1,423/242,835 39% improvement All studies 39% 0.61 [0.54-0.69] 1,825/566,624 1,423/242,835 39% improvement 33 exercise COVID-19 studies c19early.com/ex May 2022 Tau​2 = 0.06, I​2 = 68.8%, p < 0.0001 Effect extraction pre-specified(most serious outcome, see appendix) Favors exercise Favors inactivity
Figure 4. Random effects meta-analysis for all studies with pooled effects. This plot shows pooled effects, discussion can be found in the heterogeneity section, and results for specific outcomes can be found in the individual outcome analyses. Effect extraction is pre-specified, using the most serious outcome reported. For details of effect extraction see the appendix.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Zhang 26% 0.74 [0.48-1.14] n/a n/a Improvement, RR [CI] Treatment Control Yates 45% 0.55 [0.38-0.79] 72/163,912 62/30,119 Cho 53% 0.47 [0.26-0.87] case control Sallis 59% 0.41 [0.22-0.76] 11/3,118 170/6,984 Christensen 63% 0.37 [0.16-0.85] 543 (n) 529 (n) Yuan 91% 0.09 [0.01-1.65] 0/61 6/103 Lee 74% 0.26 [0.07-0.99] 2/11,072 32/41,293 Baynouna AlKetbi 98% 0.01 [0.00-0.44] n/a n/a Ahmadi 30% 0.70 [0.54-0.89] 160/232,613 112/95,221 Hamrouni 29% 0.71 [0.55-0.92] 138/106,006 109/47,827 Steenkamp 42% 0.58 [0.50-0.68] 29,469 (n) 13,366 (n) Salgado-Aranda 83% 0.17 [0.05-0.56] 4/223 41/297 Tau​2 = 0.03, I​2 = 45.2%, p < 0.0001 Prophylaxis 44% 0.56 [0.47-0.67] 387/547,017 532/235,739 44% improvement All studies 44% 0.56 [0.47-0.67] 387/547,017 532/235,739 44% improvement 12 exercise COVID-19 mortality results c19early.com/ex May 2022 Tau​2 = 0.03, I​2 = 45.2%, p < 0.0001 Favors exercise Favors inactivity
Figure 5. Random effects meta-analysis for mortality results.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ de Souza 73% 0.27 [0.07-1.06] 3/611 6/327 Improvement, RR [CI] Treatment Control Steenkamp 45% 0.55 [0.47-0.64] 29,469 (n) 13,366 (n) Tau​2 = 0.01, I​2 = 3.4%, p < 0.0001 Prophylaxis 46% 0.54 [0.43-0.68] 3/30,080 6/13,693 46% improvement All studies 46% 0.54 [0.43-0.68] 3/30,080 6/13,693 46% improvement 2 exercise COVID-19 mechanical ventilation results c19early.com/ex May 2022 Tau​2 = 0.01, I​2 = 3.4%, p < 0.0001 Favors exercise Favors inactivity
Figure 6. Random effects meta-analysis for ventilation.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Sallis 42% 0.58 [0.40-0.85] 32/3,118 195/6,984 Improvement, RR [CI] Treatment Control Steenkamp 41% 0.59 [0.52-0.66] 29,469 (n) 13,366 (n) Tau​2 = 0.00, I​2 = 0.0%, p < 0.0001 Prophylaxis 41% 0.59 [0.53-0.66] 32/32,587 195/20,350 41% improvement All studies 41% 0.59 [0.53-0.66] 32/32,587 195/20,350 41% improvement 2 exercise COVID-19 ICU results c19early.com/ex May 2022 Tau​2 = 0.00, I​2 = 0.0%, p < 0.0001 Favors exercise Favors inactivity
Figure 7. Random effects meta-analysis for ICU admission.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Hamer 28% 0.72 [0.61-0.87] hosp. n/a n/a Improvement, RR [CI] Treatment Control Brawner 74% 0.26 [0.11-0.58] hosp. n/a n/a Sallis 53% 0.47 [0.38-0.58] hosp. 99/3,118 732/6,984 Latorre-Román 76% 0.24 [0.05-1.04] hosp. n/a n/a Brandenburg -6% 1.06 [0.23-4.79] hosp. 102 (n) 39 (n) Maltagliati 52% 0.48 [0.25-0.87] hosp. n/a n/a de Souza 34% 0.66 [0.43-0.99] hosp. 49/611 42/327 Tau​2 = 0.13, I​2 = 84.5%, p = 0.0012 Prophylaxis 42% 0.58 [0.42-0.81] 148/3,831 774/7,350 42% improvement All studies 42% 0.58 [0.42-0.81] 148/3,831 774/7,350 42% improvement 7 exercise COVID-19 hospitalization results c19early.com/ex May 2022 Tau​2 = 0.13, I​2 = 84.5%, p = 0.0012 Favors exercise Favors inactivity
Figure 8. Random effects meta-analysis for hospitalization.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Paul 38% 0.62 [0.30-1.20] no recov. n/a n/a Improvement, RR [CI] Treatment Control Kontopoulou 66% 0.34 [0.24-0.47] recov. time 42 (n) 24 (n) Tau​2 = 0.11, I​2 = 60.7%, p = 0.0036 Prophylaxis 57% 0.43 [0.24-0.76] 0/42 0/24 57% improvement All studies 57% 0.43 [0.24-0.76] 0/42 0/24 57% improvement 2 exercise COVID-19 recovery results c19early.com/ex May 2022 Tau​2 = 0.11, I​2 = 60.7%, p = 0.0036 Favors exercise Favors inactivity
Figure 9. Random effects meta-analysis for recovery.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Zhang 18% 0.82 [0.69-0.96] cases n/a n/a Improvement, RR [CI] Treatment Control Holt 17% 0.83 [0.63-1.09] cases n/a n/a Cho 10% 0.90 [0.86-0.95] cases case control Christensen 23% 0.77 [0.52-1.15] cases 55/543 77/529 Marcus 42% 0.58 [0.48-0.71] symp. case 240/10,627 134/3,708 Bielik -9% 1.09 [0.69-1.73] cases 775 (n) 365 (n) Lee 16% 0.84 [0.73-0.98] cases 291/11,072 1,293/41,293 Nguyen 20% 0.80 [0.72-0.88] symp. case 904/2,836 483/1,111 Lin 47% 0.53 [0.12-2.33] cases n/a n/a Lengelé 74% 0.26 [0.07-0.80] cases 23/229 4/12 Saadeh 9% 0.91 [0.56-1.43] symp. case 362 (n) 225 (n) Huang 66% 0.34 [0.17-0.70] cases n/a n/a Gilley -42% 1.42 [0.60-3.35] cases 172/1,917 5/79 Beydoun 43% 0.57 [0.32-1.01] cases 1,710 (n) 448 (n) Tau​2 = 0.02, I​2 = 69.4%, p < 0.0001 Prophylaxis 20% 0.80 [0.72-0.89] 1,685/30,071 1,996/47,770 20% improvement All studies 20% 0.80 [0.72-0.89] 1,685/30,071 1,996/47,770 20% improvement 14 exercise COVID-19 case results c19early.com/ex May 2022 Tau​2 = 0.02, I​2 = 69.4%, p < 0.0001 Favors exercise Favors inactivity
Figure 10. Random effects meta-analysis for cases.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Hamer 28% 0.72 [0.61-0.87] hosp. n/a n/a Improvement, RR [CI] Treatment Control Brawner 74% 0.26 [0.11-0.58] hosp. n/a n/a Zhang 26% 0.74 [0.48-1.14] death n/a n/a Tavakol 69% 0.31 [0.10-1.02] severe case 3/64 19/124 Yates 45% 0.55 [0.38-0.79] death 72/163,912 62/30,119 Holt 17% 0.83 [0.63-1.09] cases n/a n/a Cho 53% 0.47 [0.26-0.87] death case control Sallis 59% 0.41 [0.22-0.76] death 11/3,118 170/6,984 Christensen 63% 0.37 [0.16-0.85] death 543 (n) 529 (n) Latorre-Román 76% 0.24 [0.05-1.04] hosp. n/a n/a Marcus 42% 0.58 [0.48-0.71] symp. case 240/10,627 134/3,708 Yuan 91% 0.09 [0.01-1.65] death 0/61 6/103 Brandenburg -6% 1.06 [0.23-4.79] hosp. 102 (n) 39 (n) Bielik 30% 0.70 [0.40-1.21] mod. case 775 (n) 365 (n) Lee 74% 0.26 [0.07-0.99] death 2/11,072 32/41,293 Maltagliati 52% 0.48 [0.25-0.87] hosp. n/a n/a Baynouna AlKetbi 98% 0.01 [0.00-0.44] death n/a n/a Ahmadi 30% 0.70 [0.54-0.89] death 160/232,613 112/95,221 Nguyen 20% 0.80 [0.72-0.88] symp. case 904/2,836 483/1,111 Lin 47% 0.53 [0.12-2.33] cases n/a n/a de Souza 73% 0.27 [0.07-1.06] ventilation 3/611 6/327 Mohsin 19% 0.81 [0.66-0.99] severe case 86/258 224/544 Ekblom-Bak 48% 0.52 [0.30-0.92] severe case n/a n/a Lengelé 74% 0.26 [0.07-0.80] cases 23/229 4/12 Saadeh 9% 0.91 [0.56-1.43] symp. case 362 (n) 225 (n) Hamrouni 29% 0.71 [0.55-0.92] death 138/106,006 109/47,827 Huang 47% 0.53 [0.23-1.22] severe case 7/74 16/90 Steenkamp 42% 0.58 [0.50-0.68] death 29,469 (n) 13,366 (n) Gilley -42% 1.42 [0.60-3.35] cases 172/1,917 5/79 Beydoun 43% 0.57 [0.32-1.01] cases 1,710 (n) 448 (n) Salgado-Aranda 83% 0.17 [0.05-0.56] death 4/223 41/297 Kontopoulou 66% 0.34 [0.24-0.47] recov. time 42 (n) 24 (n) Tau​2 = 0.06, I​2 = 69.8%, p < 0.0001 Prophylaxis 39% 0.61 [0.54-0.69] 1,825/566,624 1,423/242,835 39% improvement All studies 39% 0.61 [0.54-0.69] 1,825/566,624 1,423/242,835 39% improvement 32 exercise COVID-19 peer reviewed trials c19early.com/ex May 2022 Tau​2 = 0.06, I​2 = 69.8%, p < 0.0001 Effect extraction pre-specified(most serious outcome, see appendix) Favors exercise Favors inactivity
Figure 11. Random effects meta-analysis for peer reviewed studies. [Zeraatkar] analyze 356 COVID-19 trials, finding no significant evidence that peer-reviewed studies are more trustworthy. They also show extremely slow review times during a pandemic. Authors recommend using preprint evidence, with appropriate checks for potential falsified data, which provides higher certainty much earlier. Effect extraction is pre-specified, using the most serious outcome reported, see the appendix for details.
Exclusions
To avoid bias in the selection of studies, we analyze all non-retracted studies. Here we show the results after excluding studies with major issues likely to alter results, non-standard studies, and studies where very minimal detail is currently available. Our bias evaluation is based on analysis of each study and identifying when there is a significant chance that limitations will substantially change the outcome of the study. We believe this can be more valuable than checklist-based approaches such as Cochrane GRADE, which may underemphasize serious issues not captured in the checklists, overemphasize issues unlikely to alter outcomes in specific cases (for example, lack of blinding for an objective mortality outcome, or certain specifics of randomization with a very large effect size), or be easily influenced by potential bias. However, they can also be very high quality.
The studies excluded are as below. Figure 12 shows a forest plot for random effects meta-analysis of all studies after exclusions.
[Brawner], unadjusted results with no group details.
[de Souza], unadjusted results with no group details. Excluded results: mechanical ventilation.
[Huang], unadjusted results with no group details. Excluded results: severe case.
[Kontopoulou], unadjusted results with no group details.
[Mohsin], unadjusted results with no group details.
[Yuan], excessive unadjusted differences between groups. Excluded results: death.
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2+ Hamer 28% 0.72 [0.61-0.87] hosp. n/a n/a Improvement, RR [CI] Treatment Control Zhang 26% 0.74 [0.48-1.14] death n/a n/a Tavakol 69% 0.31 [0.10-1.02] severe case 3/64 19/124 Yates 45% 0.55 [0.38-0.79] death 72/163,912 62/30,119 Holt 17% 0.83 [0.63-1.09] cases n/a n/a Cho 53% 0.47 [0.26-0.87] death case control Sallis 59% 0.41 [0.22-0.76] death 11/3,118 170/6,984 Christensen 63% 0.37 [0.16-0.85] death 543 (n) 529 (n) Latorre-Román 76% 0.24 [0.05-1.04] hosp. n/a n/a Marcus 42% 0.58 [0.48-0.71] symp. case 240/10,627 134/3,708 Yuan 70% 0.30 [0.09-0.92] severe case 3/61 26/103 Brandenburg -6% 1.06 [0.23-4.79] hosp. 102 (n) 39 (n) Bielik 30% 0.70 [0.40-1.21] mod. case 775 (n) 365 (n) Lee 74% 0.26 [0.07-0.99] death 2/11,072 32/41,293 Maltagliati 52% 0.48 [0.25-0.87] hosp. n/a n/a Baynouna AlKetbi 98% 0.01 [0.00-0.44] death n/a n/a Ahmadi 30% 0.70 [0.54-0.89] death 160/232,613 112/95,221 Nguyen 20% 0.80 [0.72-0.88] symp. case 904/2,836 483/1,111 Lin 47% 0.53 [0.12-2.33] cases n/a n/a de Souza 34% 0.66 [0.43-0.99] hosp. 49/611 42/327 Ekblom-Bak 48% 0.52 [0.30-0.92] severe case n/a n/a Lengelé 74% 0.26 [0.07-0.80] cases 23/229 4/12 Saadeh 9% 0.91 [0.56-1.43] symp. case 362 (n) 225 (n) Hamrouni 29% 0.71 [0.55-0.92] death 138/106,006 109/47,827 Huang 66% 0.34 [0.17-0.70] cases n/a n/a Steenkamp 42% 0.58 [0.50-0.68] death 29,469 (n) 13,366 (n) Gilley -42% 1.42 [0.60-3.35] cases 172/1,917 5/79 Beydoun 43% 0.57 [0.32-1.01] cases 1,710 (n) 448 (n) Salgado-Aranda 83% 0.17 [0.05-0.56] death 4/223 41/297 Paul 38% 0.62 [0.30-1.20] no recov. n/a n/a Tau​2 = 0.04, I​2 = 62.5%, p < 0.0001 Prophylaxis 37% 0.63 [0.56-0.71] 1,781/566,250 1,239/242,177 37% improvement All studies 37% 0.63 [0.56-0.71] 1,781/566,250 1,239/242,177 37% improvement 30 exercise COVID-19 studies after exclusions c19early.com/ex May 2022 Tau​2 = 0.04, I​2 = 62.5%, p < 0.0001 Effect extraction pre-specified(most serious outcome, see appendix) Favors exercise Favors inactivity
Figure 12. Random effects meta-analysis for all studies after exclusions. This plot shows pooled effects, discussion can be found in the heterogeneity section, and results for specific outcomes can be found in the individual outcome analyses. Effect extraction is pre-specified, using the most serious outcome reported. For details of effect extraction see the appendix.
Conclusion
More physically active people have reduced risk for COVID-19. Statistically significant improvements are seen for mortality, ventilation, ICU admission, hospitalization, recovery, and cases. 26 studies from 26 independent teams in 14 different countries show statistically significant improvements in isolation (19 for the most serious outcome). Meta analysis using the most serious outcome reported shows 39% [31‑46%] improvement. Results are similar after exclusions and similar for peer-reviewed studies. Results are robust — in exclusion sensitivity analysis 28 of 33 studies must be excluded to avoid finding statistically significant efficacy in pooled analysis. Results are consistent with the overall risk of all cause mortality based on cardiorespiratory fitness — [Laukkanen] show RR 0.55 [0.50-0.61] for the top vs. bottom tertiles.
Studies analyze exercise/physical activity levels before infection, comparing regular/moderate exercise vs. lower/no exercise. Note that risk may increase with more extreme activity levels.
Study Notes