Introduction
Methods
Protocol
Database and search criteria
Eligibility criteria
Study selection and data extraction
Data analysis
Time domain analysis | |
RR (ms) | Mean time interval between two consecutive R waves in milliseconds |
SDNN (ms) | Standard deviation of RR intervals in milliseconds |
RMSSD (ms) | Root mean square of successive differences between adjacent RR intervals in milliseconds |
Frequency domain analysis | |
TP (ms2) | Total power of RR series expressed in milliseconds squared |
HF (ms2) | Power of RR series in the high frequency band (0.15–0.40 Hz) in milliseconds squared |
HFnu (nu) | Power of RR series in the high frequency band (0.15–0.40 Hz) in normalized units |
LF/HF | Ratio between the low- (0.04–0.15 Hz) and high-frequency components of RR series |
Results
Search results and study characteristics
Authors | Country | M, n | F, n | Age M, years | Age F, years | BMI M, kg/m2 | BMI F, kg/m2 | Sample type | Psychosocial variables | Length of recording | DAY vs NIGHT | System | SR, Hz | Time domain indices | Frequency domain indices |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Beckers et al. [34] | Belgium | 141 | 135 | NR (18–71) | NR (18–71) | 25 ± 3 | 23 ± 4 | Healthy subjects | No | 24 h | Yes | ELA Medical Holter | 200 | RR, SDNN, RMSSD | TP, HF, HFnu, LF/HF (FFT—iterated analysis, windows of 128 s, 50% overlap) |
Germany | 85 | 81 | 43 ± 3 (20–70) | 42 ± 3 (20–70) | 23 ± 1 | 22 ± 1 | Healthy healthcare professionals and their family members; healthy former patients with atypical chest pain | No | 24 h | No | Tracker II, Reynolds, Hertford, UK | NR | RR, SDNN, RMSSD | NR | |
Bigger et al. [48] | USA | 202 | 72 | 57 ± 8 (40–69) | NR | NR | Healthy employees and persons who responded to newspaper advertisement | No | 24 h | No | Marquette 8000 | NR | RR | NR | |
Italy | 50 | 50 | 35 ± 5 (28–48) | 37 ± 7 (25–49) | 25 ± 3 | 23 ± 3 | Healthy healthcare professionals | Yes | 24 h | Yes | eMotion Faros 360°, Mega Electronics, Finland | 500 | RR | TP, HF (AR—iterated analysis, windows of 250 RRs, overlap of 200 RRs) | |
Extramiana et al. [50] | France | 30 | 30 | 34 ± 9 (20–50) | NR | NR | Healthy subjects | No | 24 h | Yes | Del Mar 459 Recorder, Del Mar Avionics, Irvine, California | NR | RR, SDNN, RMSSD | NR | |
Genovesi et al. [51] | Italy | 20 | 20 | 29 ± 4 (NR) | 27 ± 4 (NR) | 23 ± 2 | 21 ± 2 | Healthy sedentary subjects | No | 24 h | Yes | ELA Medical, Le Plessis Robinson, France | 200 | RR, SDNN | NR |
Hulsegge et al. [20] | Denmark | 292 | 251 | 46 ± 10 (18–68) | 27 ± 5 | Healthy blue-collar workers | Yes | 96 h | No | Actiheart monitor | NR | RR, SDNN RMSSD | TP, HF, LF/HF (NR—iterated analysis, windows of 300 s, no overlap) | ||
Jensen-Urstad et al. [52] | Sweden | 49 | 53 | NR (20–69 years) | 25 ± 3 | 23 ± 3 | Healthy healthcare professionals, students and blood donors | No | 24 h | No | Reynolds Sherpa, Reynolds Medical, Hertford, England | NR | RR, SDNN, RMSSD | TP, HF, LF/HF (AR—iterated analysis, windows of 300 s, no data about overlap) | |
Jensen-Urstad et al. [21] | Sweden | 63 | 70 | 35 ± 0 (NR) | 25 ± 2 | 23 ± 4 | Healthy subjects | Yes | 24 h | Yes | Reynolds Sherpa, Reynolds Medical, Hertford, England | NR | RR | TP, HF, LF/HF (AR—iterated analysis, windows of 300 s, no data about overlap) | |
Kashiwagi et al. [53] | Japan | 15 | 17 | 49 ± 14 (NR) | 50 ± 11 (NR) | NR | NR | Healthy subjects | No | 48 h | Yes | NR | NR | NR | HFnu (NR—iterated analysis, windows of 512 RRs every 30 min) |
Krauss et al. [54] | Germany | 63 | 76 | 41 ± NR (20–77) | 42 ± NR (20–77) | NR | NR | Healthy subjects | No | 24 h | No | Tracker II, Delmar Reynolds, Hertford, UK | NR | RR, SDNN, RMSSD | NR |
Lampert et al. [22] | USA | 87 | 70 | 30 ± 1 (18–50) | 29 ± 1 (18–50) | 28 ± 1 | 28 ± 1 | Healthy community dwelling subjects | Yes | 24 h | No | GE Seer and Seer Lite | 125 | SDNN | NR |
Li et al. [55] | USA | 35 | 60 | 55 ± 8 (NR) | 58 ± 8 (NR) | 27 ± 3 | 27 ± 6 | Healthy community dwelling subjects | No | 24 h | No | Mortara Instrument, Inc., WI, USA | 1000 | RR, SDNN, RMSSD | LF/HF (FFT—iterated analysis, windows of 300 s, no overlap) |
Lerma et al. [56] | Mexico | 20 | 30 | 29 ± NR (21–36) | 27 ± NR (21–36) | 23 ± NR (23–32) | 23 ± NR (22–27) | Healthy subjects | No | 24 h | No | Burdik-Spacelabs, 92,513, Dreefield | 200 | RR, SDNN, RMSSD | TP, HF, HFnu, LF/HF (FFT—NR) |
Marin-Farrona et al. [23] | Spain | 47 | 66 | 39 ± 6 | 39 ± 6 | 25 ± 2 | 24 ± 2 | Healthy office workers | Yes | 48 h | No | Firstbeat Bodyguard device, Firstbeat Technologies Ltd., Jyväskylä, Finland | NR | RMSSD | NR |
Molnar et al. [57] | USA | 11 | 10 | 57 ± 12 (36–76) | 57 ± 15 (36–76) | NR | NR | Healthy subjects | No | 24 h | No | Marquette 8000 T Laser Holter | NR | RR | NR |
Pitzalis et al. [58] | Italy | 44 | 45 | 26 ± 6 (NR) | 27 ± 4 (NR) | 24 ± 2 | 21 ± 3 | Normotensive subjects with and without family history of hypertension | No | 24 h | No | Del Mar Avionics Model 445A, Irvine, California, USA | NR | RR, SDNN RMSSD | NR |
Ramaekers et al. [30] | Belgium | 141 | 135 | 41 ± 14 (18–71) | 43 ± 15 (18–71) | 25 ± 3 | 23 ± 4 | Healthy subjects | No | 24 h | No | NR | 200 | RR, SDNN, RMSSD | TP, HF, HFnu, LF/HF (FFT—iterated analysis, windows of 256 s, overlap of 50%) |
Strauss et al. [24] | South Africa | 284 | 396 | 25 ± 3 (NR) | 25 ± 3 (NR) | 25 ± 5 | 26 ± 6 | Black and white healthy subjects | Yes | 24 h | No | Card(X)plore, Meditech, Budapest, Hungary | NR | RR, SDNN | HFnu, LF/HF (NR—NR) |
Sammito et al. [59] | Germany | 319 | 376 | 40 ± 10 (NR) | 40 ± 11 (NR) | 27 ± 4 | 25 ± 4 | Healthy office employees, healthcare professionals, students and military | No | 24 h | No | Schiller MT-101, Firma Schiller AG, Baar, Switzerland | 1000 | SDNN, RMSSD | HFnu, LF/HF (FFT—iterated analysis, windows of 256 s, overlap of 50%) |
Sztajzel et al. [60] | Switzerland | 14 | 18 | 29 ± 3 (NR) | NR | NR | Healthy medical students, residents and technicians | No | 24 h + 24 h | Yes | NR | NR | RR, SDNN, RMSSD | TP, HF, HFnu, LF/HF (FFT—NR) | |
Sosnowski et al. [61] | Poland | 173 | 37 | 50 ± 6 (NR) | NR | NR | Healthy subjects | No | 24 h | No | MEdilog Excel 2 System, Oxford Instruments, Abingdon, UK | NR | RR, SDNN | NR | |
Stein et al. [62] | USA | 30 | 30 | 50 ± 4 (NR) | NR | NR | Healthy subjects | No | 24 h | Yes | Marquette series 8500, Milwaukee, Wisconsin | NR | RR, SDNN, RMSSD | LF/HF (FFT—iterated analysis. Windows of 300 s, no overlap) | |
Stein et al. [25] | USA | 18 | 18 | 37 ± 9 (23–59) | NR | NR | Healthy subjects | Yes | 24 h | Yes | ACS Holter, Ontario, CA | NR | RR, SDNN, RMSSD | LF/HF (FFT—iterated analysis. Windows of 300 s, no overlap) | |
Sevre et al. [63] | Norway and Netherlands | 19 | 15 | 54 ± 3 (NR) | 51 ± 1 (NR) | 26 ± 1 | 27 ± 1 | Healthy subjects | No | 24 h | No | Marquette series 8500 | NR | RR | NR |
Umetani et al. [64] | USA | 65 | 81 | NR (30–69) | NR | NR | Healthy subjects | No | 24 h | No | Cardionostics Dura-Lite recorder (Cardionostics), Epicardia 4000 53A-01 | NR | RR, SDNN, RMSSD | NR | |
Van Hoogenhuyze et al. [65] | USA | 19 | 14 | 33 ± 7 (NR) | 34 ± 8 (NR) | NR | NR | Healthy subjects | No | 24 h | No | Marquette 8500 | NR | RR, SDNN | NR |
Effect sizes during 24-h recordings
Domain | Indices | Studies | Participants | Statistical methods | I2 (%) | Effect size (M vs F) | p value |
---|---|---|---|---|---|---|---|
Time | RR | 21 | 2711 | Std. mean difference (IV, random, 95% CI) | 77 | 0.57 [0.38, 0.75] | < 0.001 |
SDNN | 18 | 2538 | Std. mean difference (IV, fixed, 95% CI) | 48 | 0.56 [0.48, 0.64] | < 0.001 | |
RMSSD | 14 | 1531 | Std. mean difference (IV, fixed, 95% CI) | 0 | 0.18 [0.08, 0.28] | < 0.001 | |
Frequency | TP | 6 | 692 | Std. mean difference (IV, fixed, 95% CI) | 9 | 0.50 [0.34, 0.65] | < 0.001 |
HF | 6 | 692 | Std. mean difference (IV, fixed, 95% CI) | 0 | 0.14 [− 0.01, 0.29] | 0.07 | |
HFnu | 6 | 1238 | Std. mean difference (IV, fixed, 95% CI) | 0 | − 0.52 [− 0.63, − 0.40] | < 0.001 | |
LF/HF | 10 | 1641 | Std. mean difference (IV, fixed, 95% CI) | 0 | 0.59 [0.49, 0.69] | < 0.001 |
Effect sizes during daytime recordings
Effect sizes during night-time recordings
Domain | Indices | Studies | Participants | Statistical methods | I2 (%) | Effect size (M vs. F) | p value |
---|---|---|---|---|---|---|---|
Time | RR | 7 | 604 | Std. mean difference (IV, random, 95% CI) | 75 | 0.52 [0.15, 0.89] | 0.006 |
SDNN | 6 | 504 | Std. mean difference (IV, random, 95% CI) | 57 | 0.35 [0.03, 0.67] | 0.03 | |
RMSSD | 5 | 464 | Std. mean difference (IV, random, 95% CI) | 56 | 0.06 [− 0.27, 0.39] | 0.73 | |
Frequency | TP | 2 | 376 | Std. mean difference (IV, random, 95% CI) | 72 | 0.34 [− 0.09, 0.77] | 0.12 |
HF | 2 | 376 | Std. mean difference (IV, fixed, 95% CI) | 45 | 0.16 [− 0.05, 0.36] | 0.13 | |
HFnu | 2 | 308 | Std. mean difference (IV, fixed, 95% CI) | 0 | − 0.41 [− 0.64, − 0.18] | < 0.001 | |
LF/HF | 3 | 372 | Std. mean difference (IV, fixed, 95% CI) | 0 | 0.57 [0.36, 0.78] | < 0.001 |
Domain | Indices | Studies | Participants | Statistical methods | I2 (%) | Effect size (M vs. F) | p value |
---|---|---|---|---|---|---|---|
Time | RR | 8 | 1147 | Std. mean difference (IV, random, 95% CI) | 73 | 0.49 [0.21, 0.77] | < 0.001 |
SDNN | 7 | 1047 | Std. mean difference (IV, random, 95% CI) | 51 | 0.48 [0.26, 0.71] | < 0.001 | |
RMSSD | 6 | 1007 | Std. mean difference (IV, fixed, 95% CI) | 0 | 0.11 [− 0.01, 0.24] | 0.07 | |
Frequency | TP | 3 | 919 | Std. mean difference (IV, random, 95% CI) | 73 | 0.33 [0.05, 0.61] | 0.02 |
HF | 3 | 919 | Std. mean difference (IV, fixed, 95% CI) | 0 | 0.11 [− 0.02, 0.24] | 0.09 | |
HFnu | 2 | 308 | Std. mean difference (IV, fixed, 95% CI) | 0 | − 0.61 [−0.84, − 0.38] | < 0.001 | |
LF/HF | 4 | 915 | Std. mean difference (IV, fixed, 95% CI) | 2 | 0.52 [0.38, 0.65] | < 0.001 |