Summary of findings for the main comparison. Exercise versus no exercise for the occurrence, severity, and duration of acute respiratory infections.
| Exercise versus no exercise for the occurrence, severity, and duration of acute respiratory infections | ||||||
| Patient or population: healthy people Setting: university health centre Intervention: bicycle, treadmill, or walk Comparison: no exercise | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (trials) | Certainty of the evidence (GRADE) | Comments | |
| Risk with control intervention for acute respiratory infections (total) | Risk with exercise | |||||
| Number of ARI episodes per person per year Self‐reported Follow‐up: adjusted for 1 year | Median risk in study population | Rate ratio 1.00 (0.77 to 1.30) | 514 (4 trials) | ⊕⊕⊝⊝ lowa,c |
||
| 39 per 100 | 39 per 100 (30 to 51) | |||||
|
Proportion of participants who experienced at least 1 ARI over the study period Follow‐up: 12 to 52 weeks |
Median risk in study population | RR 0.88 (0.72 to 1.08) | 520 (5 trials) | ⊕⊕⊝⊝ lowa,c |
This outcome combines a wide range of follow‐up periods. | |
| 61 per 100 | 54 per 100 (44 to 66) | |||||
|
Severity of ARI symptoms Follow‐up: 8 weeks Self‐reported The lower the score the lower the symptoms |
Mean 342 points | Mean 236 points | MD 103.57 lower (198.28 lower to 8.87 lower) | 373 (2 trials) | ⊕⊕⊝⊝ lowa,b | This scale is an area under the curve (WURSS‐24 score by days of illness). The scale is composed of 19 items. All items are scored on an 8‐point Likert scale from 0 (absent or no impairment) through 1 (very mild), 3 (mild), 5 (moderate), and 7 (severe). The scale assesses symptoms over the last 24 hours. Global severity calculated as the area under the curve using WURSS‐24 scores for y‐axis and duration of ARI illness as x‐axis. |
|
Number of symptom days during follow‐up period Follow‐up: 12 weeks |
Mean 7.66 days | Mean 6.34 days | MD 2.24 lower (3.5 lower to 0.98 lower) | 483 (4 trials) | ⊕⊕⊝⊝ lowa,b | |
| Number of symptom days per episode of illness | Mean 7.93 days | Mean 7.42 days | MD 0.44 lower (2.33 lower to 1.46 higher) | 557 (6 trials) | ⊕⊕⊝⊝ lowa,b | |
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). ARI: acute respiratory infection; CI: confidence interval; MD: mean difference; RR: risk ratio; WURSS‐24: Wisconsin Upper Respiratory Symptom Survey | ||||||
| GRADE Working Group grades of evidence High certainty: We are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: We are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: Our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: We have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect. | ||||||
aLimitations in study design and implementation. Risk of selection bias and lack of blinding; allocation concealment not reported in the trials. bImprecision of results. The confidence interval is very wide because of a small number of participants. cInconsistency of results. Heterogeneity between trials may be due to differences in populations, intensity and duration of the intervention, and length of follow‐up period.