Table 3. MeanRR, SDNN, RMSSD and heart rate during rest in sitting and supine position.
| Placebo | Caffeine | ||||
|---|---|---|---|---|---|
| Pre | Post | Pre | Post | Δ p-value | |
| MeanRR (supine) [ms] | |||||
| AB | 1076 [823; 1273] | 1240 [895; 1353]* | 1108 [881; 1436] | 1176 [1004; 1477] | 0.53 |
| P | 922 [770; 1153] | 1049 [910; 1262]* | 974 [781; 1262] | 1078 [857; 1449]* | 0.77 |
| T | 1158 [908; 1326] | 1247 [1036; 1415]* | 1229 [829; 1355] | 1347 [975; 1647]* | 0.40 |
| MeanRR (sitting) [ms] | |||||
| AB | 1088 [761; 1276] | 1194 [786; 1377]* | 991 [803; 1401] | 1130 [892; 1358] | 0.94 |
| P | 864 [707; 1111] | 906 [756; 1180]* | 946 [736; 1060] | 995 [758; 1286]* | 0.21 |
| T | 1130 [789; 1307] | 1142 [900; 1223] | 1139 [757; 1213] | 1217 [867; 1633]* | 0.50 |
| SDNN (supine) [ms] | |||||
| AB | 44 [12; 82] | 48 [11; 111] | 34 [18; 94] | 57 [18; 98]* | 0.91 |
| P | 28 [10; 79] | 36 [12; 107] | 31 [13; 60] | 39 [12; 69] | 0.09 |
| T | 31 [11; 91] | 38 [25; 87] | 38 [8; 66] | 42 [20; 65] | 0.50 |
| SDNN (sitting) [ms] | |||||
| AB | 49 [14; 89] | 50 [17; 95] | 39 [15; 99] | 53 [19; 107] | 0.75 |
| P | 29 [13; 95] | 42 [14; 95]* | 33 [17; 61] | 33 [12; 74] | 0.09 |
| T | 30 [6; 42] | 35 [21; 66] | 26 [7; 62] | 33 [22; 66] | 0.61 |
| RMSSD (supine) [ms] | |||||
| AB | 50 [7; 126] | 58 [9; 158]* | 40 [21; 156] | 71 [20; 130] | 0.58 |
| P | 34 [7; 100] | 43 [13; 136]* | 35 [9; 70] | 41 [9; 102] | 0.11 |
| T | 41 [14; 130] | 55 [33; 126] | 52 [8; 99] | 50 [27; 108] | 0.74 |
| RMSSD (sitting) [ms] | |||||
| AB | 53 [10; 138] | 65 [10; 147] | 30 [15; 161] | 54 [21; 140]* | 1.0 |
| P | 32 [9; 100] | 38 [9; 107] | 32 [11; 56] | 35 [7; 70] | 0.44 |
| T | 32 [7; 51] | 40 [26; 84] | 29 [7; 82] | 43 [23; 103] | 0.73 |
| HR (supine) [1/min] | |||||
| AB | 56 [47; 73] | 49 [45; 67]* | 54 [42; 68] | 52 [41; 61] | 0.24 |
| P | 65 [52; 78] | 57 [48; 66]* | 62 [48; 77] | 56 [41; 71]* | 0.68 |
| T | 52 [45; 66] | 48 [42; 58]* | 49 [44; 72] | 45 [36; 62]* | 0.40 |
| HR (sitting) [1/min] | |||||
| AB | 56 [47; 79] | 51 [44; 76]* | 60 [43; 75] | 54 [45; 68] | 0.94 |
| P | 70 [54; 85] | 66 [51; 79]* | 64 [57; 82] | 61 [47; 79]* | 0.52 |
| T | 53 [46; 76] | 53 [49; 67] | 53 [50; 79] | 49 [37; 69] | 0.74 |
AB = able-bodied participants; P = paraplegic participants, T = tetraplegic participants; MeanRR, = mean of the RR interval; SDNN = standard deviation of all normal RR intervals; RMSSD = the squared root of the mean squared differences of successive RRI intervals; HR = heart rate
* significant change from pre to post ingestion (p < 0.05)
Δ p-value = p-value comparing the difference between pre and post measurement of the placebo trial with the difference from the caffeine trials