Table 4. Physical activity intensity thresholds according to current physical activity guidelines and from this study (based on overall sample and stratified by sex, age, BMI and physical fitness variables).
| Intensity thresholds | Sensitivity (%) (95%CI) | Specificity (%) (95%CI) | AUC (95%CI) | |
|---|---|---|---|---|
| Current guidelines | ||||
| Moderate | 3.0 | 100 (98.8–100) | 78.8 (75.3–82.0) | 0.89 (0.88–0.91) |
| Vigorous | 6.0 | 83.1 (76.9–88.1) | 92.1 (89.9–94.0) | 0.88 (0.85–0.91) |
| Overall sample | ||||
| Moderate | 4.9 | 92.4 (88.8–95.1) | 91.5 (88.9–93.6) | 0.92 (0.90–0.94) |
| Vigorous | 6.8 | 77.2 (70.6–83.0) | 96.0 (94.3–97.3) | 0.87 (0.84–0.90) |
| Sex | ||||
| Male | ||||
| Moderate | 5.6 | 85.8 (78.7–91.2) | 96.8 (94.4–98.4) | 0.91 (0.88–0.94) |
| Vigorous | 7.2 | 98.7 (92.9–100) | 93.8 (91.0–96.0) | 0.96 (0.97–0.98) |
| Female | ||||
| Moderate | 3.8 | 96.4 (92.4–98.7) | 97.5 (94.6–99.1) | 0.97 (0.95–0.99) |
| Vigorous | 5.5 | 84.1 (76.0–90.3) | 90.2 (86.2–93.3) | 0.87 (0.83–0.91) |
| Age | ||||
| 20–39 years | ||||
| Moderate | 4.9 | 92.9 (88.5–96.0) | 91.9 (88.8–94.4) | 0.92 (0.90–0.95) |
| Vigorous | 6.6 | 84.3 (76.7–90.1) | 95.6 (93.4–97.3) | 0.90 (0.87–0.93) |
| 40–60 years | ||||
| Moderate | 4.6 | 94.6 (87.8–98.2) | 90.0 (84.8–93.9) | 0.92 (0.89–0.95) |
| Vigorous | 5.6 | 80.6 (68.6–89.6) | 92.7 (88.5–95.8) | 0.87 (0.81–0.92) |
| BMI | ||||
| Normal | ||||
| Moderate | 5.0 | 93.0 (87.9–96.5) | 91.1 (87.2–94.1) | 0.92 (0.90–0.95) |
| Vigorous | 7.0 | 80.8 (71.7–88.0) | 96.3 (93.7–98.0) | 0.89 (0.85–0.93) |
| Overweight/obesity | ||||
| Moderate | 5.0 | 86.9 (80.3–91.9) | 94.2 (90.9–96.6) | 0.91 (0.88–0.94) |
| Vigorous | 6.4 | 74.4 (64.2–83.1) | 96.0 (93.4–97.8) | 0.85 (0.81–0.90) |
| Physical fitness | ||||
| Low | ||||
| Moderate | 4.0 | 96.3 (92.6–98.5) | 94.0 (90.7–96.4) | 0.95 (0.93–0.97) |
| Vigorous | 6.4 | 70.4 (61.6–78.2) | 99.2 (97.6–99.8) | 0.84 (0.80–0.88) |
| High | ||||
| Moderate | 6.2 | 92.9 (86.4–96.9) | 99.0 (97.0–99.8) | 0.96 (0.93–0.98) |
| Vigorous | 8.2 | 92.2 (82.7–97.4) | 95.8 (93.1–97.7) | 0.94 (0.91–0.98) |
Relative intensity thresholds based on percentage of maximal oxygen uptake (light, <46%; moderate, 46–63.9%; vigorous, ≥64%) were used as criterion measure.