Table 2

Effect of respiratory protection mask use on cardiovascular responses and certainty of evidence

Outcome
(measurement unit)		Systematic reviewPopulationComparisonParticipants (included studies)Effect size
MD (95% CI)		Risk of biasCertainty of evidence
Heart rate
(measured in beats per minute (bpm))		Zheng et al12Healthy adultsSurgical mask versus no mask692 (28 RCTs/randomised crossover trials)0.96 (−1.01 to 2.93)Moderate⊕⊕◯◯*
Low
N95 respirator versus no mask391 (18 RCTs/randomised crossover trials)1.63 (−2.79 to 6.05)Moderate⊕⊕◯◯*
Low
Cloth mask versus no mask115 (5 crossover trials)−0.94 (−6.39 to 4.52)Moderate⊕⊕◯◯*
Low
Mask versus no mask (progressive exercise state)803 (31 RCTs/randomised crossover trials)−0.74 (−4.48 to 2.99)Moderate⊕⊕◯◯*
Low
Mask versus no mask (steady-state exercise)685 (25 RCTs/randomised crossover trials)2.69 (1.10 to 4.28)Moderate⊕⊕◯◯*
Low
Chen et al32Patients with COPDFace mask versus no mask97 (1 non-RCT)4.70 (−0.30 to 9.70)Moderate⊕⊕◯◯†
Low
Maximum heart rateChen et al32Patients with COPDFace mask versus no mask27 (1 randomised crossover trial)−1.90 (−10.84 to 7.04)Moderate⊕◯◯◯†
Very low
Stroke volume (measured in
millilitres (mL) per beat)		Shaw et al15Healthy adultsFace mask versus no mask26 (2 crossover trials)12.33 (−4.09 to 28.75)Moderate⊕⊕◯◯‡
Low
N95 respirator versus no mask14 (1 crossover trial)13.0 (−6.97 to 32.97)Moderate⊕◯◯◯†
Very low
Cardiac output
(measured in mL/min)		Shaw et al15Healthy adultsFace mask versus no mask26 (2 crossover trials)2.26 (−0.15 to 4.67)Moderate⊕⊕◯◯‡
Low
N95 respirator versus no mask14 (1 crossover trial)1.20 (−2.19 to 4.59)Moderate⊕◯◯◯†
Very low
Systolic blood pressure
(measured in millimetres of mercury (mm Hg))		Shaw et al15Healthy adultsFace mask versus no mask1088 (4 crossover trials and 2 retrospective observational studies)−2.23 (−5.28 to 0.82)High⊕◯◯◯§
Very low
N95 respirator versus no mask130 (3 randomised crossover trials and 1 RCT)−0.12 (−4.22 to 3.97)Moderate⊕⊕◯◯‡
Low
Chen et al32Patients with COPDFace mask versus no mask following 6MWT97 (1 non-RCT)0.40 (−4.36 to 5.16)Moderate⊕⊕◯◯†
Low
Face mask versus no mask following maximum exercise test27 (1 crossover trial)−6.80 (−24.37 to 10.77)Moderate⊕⊕◯◯†
Low
Diastolic blood pressure
(measured in mm Hg)		Shaw et al15Healthy adultsFace mask versus no mask38 (3 crossover trials)−0.96 (−5.32 to 3.40)Moderate⊕⊕◯◯‡
Low
N95 respirator versus no mask114 (2 crossover trials and 1 non-RCT)−0.23 (−3.06 to 2.60)Moderate⊕⊕◯◯‡
Low
Chen et al32Patients with COPDFace mask versus no mask at rest97 (1 non-RCT)2.70 (−0.34 to 5.74)Moderate⊕⊕◯◯‡
Low
Face mask versus no mask following 6MWT97 (1 non-RCT)−0.80 (−4.13 to 2.53)Moderate⊕⊕◯◯‡
Low
Mean arterial blood pressure
(measured in mm Hg)		Lima et al31Adult patientsFace mask versus no mask116 (6 crossover trials)−0.07 (−0.32 to 0.17)High⊕◯◯◯§
Very low

  • *Low quality of evidence is due to unexplained inconsistency and imprecise results due to small magnitude of change and wide CI.

  • †Low quality of evidence is due to imprecise results due to small magnitude of change and wide CI and some concern with risk of bias.

  • ‡Low quality of evidence is due to imprecise results due to small magnitude of change and wide CI.

  • §Low quality of evidence is due to unexplained inconsistency and imprecise results due to small magnitude of change and wide CI and some concern with risk of bias.

  • COPD, chronic obstructive pulmonary disease; MD, mean difference; 6MWT, 6 min walk test; RCT, randomised controlled trial.