Table 3.
Summary of subgroup analyses
| Outcomes | N | Mean difference (95% of CI) | p | I2 (p) |
|---|---|---|---|---|
| BM | ||||
| Age: ≥ 40 years | 6 | -0.94 (-2.26, 0.38) | 0.16 | 0% (0.99) |
| Age: < 40 years | 6 | -0.87 (-2.09, 0.34) | 0.16 | 0% (0.64) |
| FiO2: ≥ 15% | 8 | -0.85 (-1.77, 0.06) | 0.07 | 0% (0.99) |
| FiO2: < 15% | 4 | -2.00 (-6.29, 2.30) | 0.36 | 0% (0.58) |
| Hypoxic dose ≥ 50 km·h | 7 | -1.26 (-2.50, -0.02) | 0.06 | 0% (0.84) |
| Hypoxic dose < 50 km·h | 5 | -0.52 (-1.80. 0.77) | 0.43 | 0% (0.99) |
| Frequency: ≥ 4 days/week | 5 | -2.27 (-4.98, 0.44) | 0.10 | 0% (0.72) |
| Frequency: < 4 days/week | 7 | -0.73 (-1.68, 0.21) | 0.13 | 0% (0.99) |
| Session length: ≥ 60 min | 10 | -0.89 (-1.80, 0.01) | 0.05 | 0% (0.94) |
| Session length: < 60 min | 2 | -1.25 (-7.55, 5.06) | 0.70 | 0% (0.89) |
| Duration: ≥ 8 weeks | 3 | -1.30 (-3.36, 0.75) | 0.21 | 4.2% (0.35) |
| Duration: < 8 weeks | 9 | -0.73 (-1.90, 0.44) | 0.22 | 0% (0.99) |
| BMI | ||||
| Age: ≥ 40 years | 4 | 0.08 (-1.40, 1.55) | 0.92 | 0% (0.91) |
| Age: < 40 years | 5 | -0.86 (-1.88, 0.15) | 0.10 | 0% (0.63) |
| FiO2: ≥ 15% | 6 | 0.20 (-1.33, 1.73) | 0.07 | 0% (0.86) |
| FiO2: < 15% | 3 | -0.85 (-1.75, 0.06) | 0.80 | 0% (0.48) |
| Hypoxic dose ≥ 50 km·h | 4 | -1.04 (-3.03, 0.95) | 0.31 | 44.6% (0.14) |
| Hypoxic dose < 50 km·h | 5 | -0 38 (-1 31, 0.55) | 0.42 | 0% (0.99) |
| Frequency: ≥ 4 days/week | 2 | 0.46 (-1.63, 2.55) | 0.67 | 0% (0.67) |
| Frequency: < 4 days/week | 7 | -0.24 (-1.09, 0.60) | 0.08 | 0% (0.63) |
| Session length: ≥ 60 min | 6 | -0.74 (-1.58, 0.10) | 0.09 | 0% (0.44) |
| Session length: < 60 min | 3 | -0.05 (-1.46, 1.37) | 0.95 | 0% (0.74) |
| Duration: ≥ 8 weeks | 2 | 0.46 (-1.63, 2.55) | 0.67 | 0% (0.67) |
| Duration: < 8 weeks | 7 | -0.74 (-1.58, 0.10) | 0.08 | 0% (0.56) |
| LBM | ||||
| Age: ≥ 40 years | 2 | 0.29 (-5.43, 6.02) | 0.92 | 0% (0.82) |
| Age: < 40 years | 2 | 1.05 (-4.03, 6.13) | 0.69 | 0% (0.98) |
| FiO2: ≥ 15% | 2 | 0.95 (-4.87, 6.77) | 0.75 | 0% (0.69) |
| FiO2: < 15% | 2 | 0.54 (-4.48, 5.56) | 0.83 | 0% (0.92) |
| FBM | ||||
| Age: ≥ 40 years | 6 | -0.43 (-2.50, 1.64) | 0.69 | 0% (0.99) |
| Age: < 40 years | 4 | -1.84 (-3.66, -0.02) | 0.05 | 0% (0.97) |
| FiO2: ≥ 15% | 5 | -1.54 (-3.55, 0.47) | 0.13 | 0% (0.94) |
| FiO2: < 15% | 5 | -0.95 (-2.82, 0.92) | 0.32 | 0% (0.74) |
| Hypoxic dose ≥ 50 km·h | 7 | -1.54 (-3.09, -0.02) | 0.05 | 0% (0.93) |
| Hypoxic dose < 50 km·h | 3 | -0.16 (-3.03, 2.72) | 0.91 | 0% (0.77) |
| Frequency: ≥ 4 days/week | 5 | -1.78 (-3.46, -0.01) | < 0.05 | 0% (0.89) |
| Frequency: < 4 days/week | 5 | -0.09 (-2.47, 2.30) | 0.95 | 0% (0.97) |
| Session length: ≥ 60 min | 8 | -1.24 (-2.70, 0.21) | 0.09 | 0% (0.90) |
| Session length: < 60 min | 2 | -1.06 (-5.08, 2.97) | 0.61 | 0% (0.74) |
| Duration: ≥ 8 weeks | 2 | -1.99 (-4.73, 0.75) | 0.16 | 0% (0.97) |
| Duration: < 8 weeks | 8 | -0.97 (-2.55, 0.61) | 0.23 | 0% (0.97) |
| WC | ||||
| Age: ≥ 40 years | 3 | -0.20 (-4.55, 4.15) | 0.93 | 0% (0.94) |
| Age: < 40 years | 2 | -1.05 (-6.63, 4.52) | 0.71 | 0% (0.70) |
| FiO2: ≥ 15% | 3 | -1.26 (-6.04, 3.51) | 0.60 | 0% (0.94) |
| FiO2: < 15% | 2 | 0.27 (-4.66, 5.91) | 0.92 | 0% (0.98) |
| Hypoxic dose ≥ 50 km·h | 2 | 0.27 (-4.66, 5.19) | 0.92 | 0% (0.98) |
| Hypoxic dose < 50 km·h | 3 | -1.26 (-6.04, 3.51) | 0.60 | 0% (0.93) |
| TC | ||||
| Age: ≥ 40 years | 5 | 9.75 (-2.95, 22.45) | 0.13 | 0% (0.92) |
| Age: < 40 years | 3 | -9.87 (-20.74,1.01) | 0.08 | 0% (0.66) |
| FiO2: ≥ 15% | 4 | -7.93 (-18.58, 2.73) | 0.15 | 0% (0.57) |
| FiO2: < 15% | 4 | 8.02 (-5.06, 21.09) | 0.23 | 0% (0.67) |
| Hypoxic dose ≥ 50 km·h | 6 | 0.45 (-10.98, 11.88) | 0.93 | 28.4% (0.22) |
| Hypoxic dose < 50 km·h | 2 | -2.12 (-28.07, 23.84) | 0.87 | 0% (0.82) |
| Frequency: ≥ 4days/week | 4 | -2.82 (-16.74,11.07) | 0.69 | 33.4% (0.21) |
| Frequency: < 4days/week | 4 | 5.61 (-9.94, 21.16) | 0.48 | 0% (0.71) |
| Session length: ≥ 60 min | 2 | 0.01 (-11.48, 11.50) | 0.99 | 28.5% (0.22) |
| Session length: < 60 min | 6 | 0.73 (-24.62, 26.09) | 0.95 | 0% (0.92) |
| Duration: ≥ 8 weeks | 5 | 9.93 (-0.48, 20.35) | 0.32 | 0% (0.37) |
| Duration: < 8 weeks | 6 | -4.11 (-13.23, 5.02) | 0.38 | 0% (0.47) |
| TG | ||||
| Age: ≥ 40 years | 5 | -8.56 (-37.83, 20.70) | 0.57 | 0% (0.43) |
| Age: < 40 years | 4 | -10.93 (-20.78, -1.08) | 0.08 | 8.1% (0.35) |
| FiO2: ≥ 15% | 6 | -13.28 (-23.49, -3.08) | < 0.05 | 0% (0.69) |
| FiO2: < 15% | 3 | 20.98 (-16.60, 58.55) | 0.27 | 0% (0.59) |
| Hypoxic dose ≥ 50 km·h | 5 | -11.99 (-23.26, -0.73) | < 0.05 | 0.1% (0.40) |
| Hypoxic dose < 50 km·h | 4 | -7.25 (-28.02, 13.53) | 0.49 | 0% (0.39) |
| Frequency: ≥ 4 days/week | 2 | -20.95 (-61.42, 19.52) | 0.31 | 27.1% (0.24) |
| Frequency: < 4 days/week | 7 | -6.00 (-23.31, 11.31) | 0.50 | 0% (0.51) |
| Session length: ≥ 60 min | 7 | -10.80 (-20.85, -0.70 | < 0.05 | 0% (0.46) |
| Session length: < 60 min | 2 | -22.68 (-94.91, 49.55) | 0.59 | 31.6% (0.23) |
| Training duration: ≥ 8 weeks | 3 | -2.38 (-36.04, 31.28) | 0.89 | 12.4% (0.32) |
| Training duration: < 8 weeks | 6 | -11.78 (-22.16, -1.40) | < 0.05 | 0% (0.47) |
| LDL-C | ||||
| Age: ≥ 40 years | 5 | -2.04 (-7.61, 3.51) | 0.47 | 0% (0.83) |
| Age: < 40 years | 5 | -0.46 (-14.05, 13.13) | 0.94 | 0% (0.86) |
| FiO2: ≥ 15% | 7 | -3.77 (-7.03, -0.52) | < 0.05 | 0% (0.79) |
| FiO2: < 15% | 3 | -2.94 (-17.82, 11.93) | 0.69 | 0% (0.68) |
| Hypoxic dose ≥ 50 km·h | 5 | -2.96 (-7.86, 1.94) | 0.34 | 10.8% (0.34) |
| Hypoxic dose < 50 km·h | 5 | 0.54 (-10.78, 11.86) | 0.96 | 0% (0.96) |
| Frequency: ≥ 4 days/week | 4 | -1.98 (-8.84, 4.87) | 0.57 | 32% (0.22) |
| Frequency: < 4 days/week | 6 | 0.47 (-10.10, 11.05) | 0.92 | 0% (0.51) |
| Session length: ≥ 60 min | 8 | -3.85 (-7.06, -0.64) | < 0.05 | 0% (0.46) |
| Session length: < 60 min | 2 | 2.94 (-20.98, 26.87) | 0.80 | 0% (0.47) |
| HDL-C | ||||
| Age: ≥ 40 years | 7 | 1.05 (-2.68, 4.78) | 0.58 | 0% (0.97) |
| Age: < 40 years | 4 | -6.67 (-16.00, 2.66) | 0.16 | 51.4% (0.10) |
| FiO2: ≥ 15% | 7 | -2.55 (-9.40, 4.29) | 0.46 | 54.4% (0.04) |
| FiO2: < 15% | 4 | 0.43 (-4.52, 5.39) | 0.86 | 5.4% (0.36) |
| Hypoxic dose ≥ 50 km·h | 7 | -2.42 (-9.12, 4.28) | 0.47 | 65.5% (0.01) |
| Hypoxic dose < 50 km·h | 4 | -0.80 (-6.97, 5.36) | 0.79 | 0% (0.94) |
| Frequency: ≥ 4 days/week | 4 | -4.10 (-14.09, 6.06) | 0.43 | 78.5% (0.01) |
| Frequency: < 4 days/week | 7 | -0.73 (-5.44, 3.97) | 0.76 | 0% (0.79) |
| Session length: ≥ 60 min | 9 | -1.24 (-6.18, 3.68) | 0.62 | 49.9% (0.04) |
| Session length: < 60 min | 2 | -5.63 (-17.72, 6.45) | 0.36 | 15.0% (0.27) |
| Training duration: ≥ 8 weeks | 3 | -0.53 (-10.19, 9.12) | 0.91 | 40.8% (0.04) |
| Training duration: < 8 weeks | 8 | -2.13 (-7.54, 3.26) | 0.43 | 51.1% (0.18) |
| Insulin | ||||
| Age: ≥ 40 years | 3 | 0.23 (-3.62, 4.08) | 0.91 | 9.4% (0.33) |
| Age: < 40 years | 2 | 1.03 (-2.28, 4.34) | 0.54 | 9.5% (0.29) |
| FiO2: ≥ 15% | 3 | 0.26 (-3.17, 3.69) | 0.88 | 9.1% (0.33) |
| FiO2: < 15% | 2 | 1.19 (-2.46, 4.85) | 0.52 | 4.7% (0.31) |
| Session length: ≥ 60 min | 3 | 1.37 (-1.47, 4.21) | 0.34 | 0% (0.39) |
| Session length: < 60 min | 2 | -0.74 (-4.55, 3.07) | 0.70 | 0% (0.38) |
| HOMA-IR | ||||
| Age: ≥ 40 years | 2 | -0.04 (-0.59, 0.50) | 0.88 | 0% (0.40) |
| Age: < 40 years | 3 | -0.19 (-0.41, 0.02) | 0.08 | 11.7% (0.32) |
| FiO2: ≥ 15% | 3 | -0.24 (-0.35, -0.13) | < 0.05 | 0% (0.79) |
| FiO2: < 15% | 2 | 0.14 (-0.33, 0.61) | 0.56 | 0% (0.50) |
| Session length: ≥ 60 min | 3 | -0.19 (-0.41, 0.02) | 0.08 | 11.7% (0.32) |
| Session length: < 60 min | 2 | -0.04 (-0.59, 0.50) | 0.88 | 0% (0.40) |
N: Number of studies; CI: confidence interval; FiO2: inspired fraction of oxygen; BM: body mass; BMI: body mass index; LBM: lean body mass; FBM: fat body mass; WC: waist circumference; HC: hip circumference; WHR: waist-to-hip ratio; TC: total cholesterol; TG: triglyceride; LDL-C: low-density lipoprotein cholesterol; HDL-C: high- density lipoprotein cholesterol; HOMA-IR: homeostasis model assessment of insulin resistance. Bold text signifes statistically significant results