Table 1.
Summary of characteristics of studies included in this systematic review and meta-analysis.
| Study | Country/City | Study design | # of study participants (include to analyses) | Study participants | Sex(F/M) | Age (Ave ± SD) | BMI (Ave ± SD) | Intervention duration | Study duration | Health outcomes |
|---|---|---|---|---|---|---|---|---|---|---|
| Han et al. (2021a) | China/Tianjin | Randomized, Double-Blinded, Crossover Intervention Study (participants were blinded and the research assistants equipping BP and HRV measurement devices). | 39 (39) | Healthy university students | F: 20 M: 19 | 22.7 (range: 20–29) | 21.0 (range: 15.6–29.4) | 2-h near- roadway during the early morning rush hour | November 2014 to January 2015 | SBP, DBP, HR, HRV (SDNN, rMSSD, pNN50, HF, LF and VLF) |
| Faridi et al. (2021) | Iran/Tehran | Randomized Crossover Study | 30 (26) | Healthy college students | M: 26 | 25.0 ± 2.6 | 23.2 ± 3.04 | 48-h in indoor dormitory; a week washout period | February 14th to 23rd, 2019 | SBP, DBP, PPa, MAP, SDNN, rMSSD, pNN50, VLFb, TPc, TBd, LF, HF, LF/HF ratio, HR), blood biomarkers (hs- TnTe, WBCf, HGBg, HCTh and platelet) |
| Lim et al. (2020) | Korea/Seoul | Quasi-Experimental Study (Randomization) | 21 (21) | Elderly without any clinically- diagnosed Chronic diseases | F: 21 | 72.7 ± 3.8 | Height: 152.5 ± 5.3 and Weight: 56.6 ± 6.5 | 3 weeks (6 days) wear mask until the health examination and for as long as possible except while eating, sleeping, and washing | May 2018 (three weeks) | SBP, DBP, MAP, PP, lung function (FEV1i, FVC j, FEV1/FVCk, and FEF25–75l). |
| Morishita et al. (2019) | USA/Michigan | Randomized Single-Blind Crossover Study | 50 (50) | Nonsmoking healthy adults aged 18–65 years | F: 36 M: 14 | 36 ± 14 | 26.1 ± 4.7 | 2-h near- roadway exposures; a weekend washout period | During warm months (May to October) 2017–2018 to avoid exposures to excessively cold temperatures | SBP, DBP, aortic hemodynamics, SDNN, LF, HF, LF/HF ratio |
| Yang et al. (2018b) | China/ Beijing | Randomized Crossover Study | 40 (39) | Healthy college students | F: 18 M: 21 | 21.2 ± 1.7 |
21.6 ± 1.7 | 4-h in subway system; a 2- week washout period | From 11 March to May 28, 2017 | SBP, DBP, MAP, PP, SDNN, rMSSD, pNN50, TP, LF, HF, LF/HF ratio, HR |
| Shi et al. (2017) | China/ Shanghai | Randomized Crossover Trial | 30 (24) | Healthy college students | F: 11 M: 13 | 23 | 22 ± 4 | 48-h in campus dormitory rooms; a 3- week washout period | From 21 March to April 13, 2014 | SBP, DBP, SDNN, SDANN, rMSSD, pNN50, VLF, LF, HF, LF/HF ratio, HR, Circulating biomarkers (Fibrinogen, P- selectin, VCAM-1 m, ET-1 n and vWF) |
| Langrish et al. (2012) | China/ Beijing | Prospective Randomized Open Blinded End Point (PROBE) Crossover | 102 (98) | Patients with a history of coronary heart disease | F: 13 M: 85 | 62 ± 7 | 26 ± 3 | wear the PFR for 24 h prior to the study day and 24 h of the study day; a week washout period | Between March and May 2009 | SBP, DBP, MAP, SDNN, rMSSD, pNN50, LF, HF, HF/LF ratio, LFn, HFn, HR, Ischemic burden (Inferior (II) territory, Anterior (V2) territory, Lateral (V5) territory, Sum (II + V2 + V5) |
| Langrish et al. (2009b) | China/Beijing | Open-Label Cross-Over Randomized Controlled Trial | 15 (15) | Healthy volunteers | F: 13 M: 2 | Median: 28 (min-max: 20–45) | 20.5 (95% CI, 19.3–21.7) | wear the PFR for 24 h prior to the study day and 24 h of the study day; a week washout period | August 2008 | SBP, DBP, MAP, Triangular Index, SDNN, rMSSD, pNN50, LF, HF, HF/LF ratio, LFn, HFn, HR |
Standard deviation of the averages of NN intervals in all 5-min segments of the entire recording.
Percentage of number of NN interval with difference ≥50 ms
Lower in the very low frequency band (0.01–0.04 Hz).
Total power.
C-reactive protein.
Platelet factor.
VonWillebrand Factor.
α2-macroglobulin.
α-acid glycoprotein.
Serum amyloid protein.
Tumor necrosis factor.
Granulocyte macrophage colony-stimulating factor.
Interferon Gamma.
Pulse pressure.
Power in the very low frequency band (0.01–0.04 Hz).
The area under the spectral curve between 0.01 and 0.4 Hz.
Total beats.
, high-sensitive cardiac troponin.
White Blood Cells.
Hemoglobin.
Hematocrit.
Forced expiratory volume in 1 Second [L].
Forced vital capacity [L].
The ratio of FEV1 to FVC [%].
Forced expiratory flow at 25%–75% of the FVC [L/s]).
Vascular cell adhesion molecule-1.
Endothelin-1.