Table 3. Cardiorespiratory and heart rate variability responses to 10 minutes of 70o upright tilt with or without the use of Q-collar.
| Men | Women | |||||||
|---|---|---|---|---|---|---|---|---|
| No Collar | Collar | No Collar | Collar | |||||
| Baseline | Tilt | Baseline | Tilt | Baseline | Tilt | Baseline | Tilt | |
| cBRS (ms/mmHg)† | 22.3±11.6 | 6.7±1.9* | 20.4±7.6 | 6.4±2.5* | 55.2±19.8 | 17.6±9.1* | 48.6±19.9 | 20.9±7.5* |
| SDNN (ms) | 65.8±17.4 | 48.7±13.0* | 81.1±26.4 | 54.5±19.5* | 67.3±34.5 | 46.1±9.6* | 64.2±25.7 | 53.3±25.0* |
| RMSSD (ms) | 50.9±19.3 | 21.4±6.3* | 56.8±24.4 | 27.8±15.3* | 54.2±27.6 | 22.7±6.9* | 49.5±22.1 | 26.0±131* |
| pRR50 (%) | 28.2±17.2 | 4.0±3.2* | 31.3±16.5 | 6.6±6.1* | 25.8±19.1 | 3.6±5.4* | 22.1±17.1 | 7.3±10.7* |
| Total Power (μs2) | 5010±2878 | 2204±978* | 7968±5435 | 3133±1856* | 4826±4618 | 2461±1168* | 5377±4992 | 2980±2271* |
| LF (nu) | 51.3±15.9 | 85.6±8.9* | 58.2±10.4 | 79.9±14.5* | 47.3±10.1 | 79.6±9.9* | 55.2±17.5 | 78.7±9.0* |
| HF (nu) | 47.5±15.7 | 15.3±9.2* | 40.4±11.0 | 20.7±14.5* | 51.7±10.0 | 21.4±9.8* | 43.6±16.7 | 21.9±8.5* |
| LF/HF | 1.53±1.15 | 8.62±4.44* | 1.70±0.81 | 8.84±6.2* | 1.01±0.41 | 4.93±2.30* | 1.99±1.71 | 5.56±4.95* |
| SD1 (ms) | 36.0±13.7 | 15.1±4.5* | 40.2±17.3 | 19.7±10.9* | 38.4±19.6 | 16.1±4.9* | 35.1±15.6 | 18.4±9.3* |
| SD2 (ms) | 84.9±23.5 | 67.1±18.1* | 106.7±34.7 | 74.2±26.0* | 86.9±44.9 | 62.9±13.4* | 83.3±33.7 | 72.9±34.2* |
| Heart rate (bpm) | 63.5±7.2 | 86.5±8.5* | 62.4±7.1 | 78.3±10.2* | 63.8±5.3 | 83.7±9.8* | 65.9±6.9 | 83.6±9.5* |
| SBP (mmHg)† | 136.3±14.5 | 128.4±15.8 | 135.0±6.1 | 132.0±8.2 | 106.9±9.7 | 102.0±11.8 | 109.0±7.7 | 106.3±10.7 |
| DBP (mmHg) | 74.2±5.0 | 78.4±5.4 | 72.8±8.0 | 79.1±5.0 | 71.4±10.2 | 71.8±9.3 | 76.7±7.9 | 77.1±8.0 |
| MAP (mmHg)† | 90.5±5.0 | 92.6±6.3 | 89.6±7.3 | 94.5±4.4 | 82.4±8.6 | 81.2±9.0 | 87.4±7.4 | 86.6±8.2 |
| CPP (mmHg)† | 90.5±5.0 | 76.5±6.2* | 89.6±7.3 | 78.4±4.4* | 82.4±8.6 | 69.5±11.2* | 87.4±7.4 | 72.9±8.6* |
| MCA mean (cm/s)† | 59.8±9.4 | 52.4±10.4* | 58.0±9.8 | 50.4±7.9* | 66.8±7.2 | 56.2±7.1* | 66.8±7.6 | 53.5±6.6* |
| MCA systolic (cm/s) | 96.1±14.9 | 84.5±16.4* | 96.1±13.9 | 84.0±11.0* | 100.9±12.2 | 87.6±10.2* | 102.6±15.8 | 90.2±9.6* |
| MCA diastolic (cm/s) | 40.4±6.8 | 36.1±8.0* | 38.5±7.8 | 33.8±7.3* | 44.3±6.1 | 38.6±7.1* | 43.4±7.5 | 32.4±9.6* |
| Resistance index | 0.58±0.03 | 0.57±0.04 | 0.60±0.04 | 0.60±0.06 | 0.56±0.07 | 0.56±0.07 | 0.57±0.09 | 0.63±0.11 |
| Pulsatility index | 0.93±0.06 | 0.93±0.10 | 1.01±0.11 | 1.02±0.16 | 0.85±0.17 | 0.89±0.20 | 0.88±0.22 | 1.12±0.42 |
| CVRi (mmHg/cm/s)† | 1.57±0.31 | 1.55±0.36 | 1.63±0.43 | 1.60±0.37 | 1.25±0.17 | 1.24±0.15 | 1.33±0.17 | 1.34±0.14 |
| ETCO2 (mmHg) | 39.1±2.9 | 38.2±4.2 | 37.3±4.7 | 36.1±3.9 | 35.1±4.9 | 31.9±5.3 | 38.1±4.3 | 35.7±4.3 |
| ETO2 (mmHg) | 117.2±2.6 | 118.2±4.8* | 116.4±5.8 | 120.1±4.3* | 118.9±4.6 | 122.6±5.2* | 113.9±6.5 | 118.5±4.0* |
| RR (breath/min) | 16.6±1.7 | 17.9±2.1 | 16.7±1.8 | 16.9±2.0 | 18.8±4.1 | 19.4±4.9 | 17.3±4.6 | 17.2±3.8 |
| Qi (L/min/m2)† | 4.0±0.5 | 4.2±0.5 | 3.9±0.5 | 4.0±0.5 | 3.7±0.4 | 3.7±0.2 | 3.6±0.3 | 3.7±0.1 |
| SVi (mL/m2)† | 62.9±5.6 | 48.2±3.2* | 63.3±6.4 | 51.8±5.1* | 58.9±7.5 | 45.4±5.8* | 55.5±4.6 | 45.1±5.0* |
| TPRi (mmHg/L/min/m2) | 23.2±2.9 | 22.7±3.2 | 23.1±2.4 | 23.9±2.7 | 22.7±5.0 | 21.9±3.4 | 24.3±2.6 | 23.4±2.4 |
cBRS is cardiovagal baroreceptor sensitivity; SDNN is the standard deviation between R-R intervals; RMSSD is the square root of the mean squared differences between adjacent beats; pRR50 is the proportion of RR interval differences greater than 50ms divided by total beats; LF is low frequency; HF is high frequency; nu is normalized unit; SD1 is the width of a Poincaré plot; SD2 is the length of a Poincaré plot; SBP is systolic blood pressure; DBP is diastolic blood pressure; MAP is mean arterial blood pressure; CPP is cerebral perfusion pressure; MCA is middle cerebral artery; CVRi is cerebrovascular resistance index; ETCO2 is end-tidal carbon dioxide; ETO2 is end-tidal oxygen; RR is respiratory rate; Qi is cardiac output index; SVi is stroke volume index; TPRi is total peripheral resistance index
*indicates a main effect of tilt
†indicates a main effect of sex; Values are mean ± 95% Confidence Interval