Table 2.
Hemodynamic response to lower body negative pressure (LBNP) and handgrip exercise (HG)
| LBNP | HG | |||
|---|---|---|---|---|
| Baseline | ∆ (%) | Baseline | ∆ (%) | |
| BPmean (mmHg) | ||||
| Young | 90 ± 9 | −3 ± 4a | 94 ± 9 | 8 ± 3a |
| Middle aged | 96 ± 8 | −8 ± 4a , b | 98 ± 7 | 10 ± 6a |
| Old | 101 ± 11b | −4 ± 6 | 103 ± 12b | 13 ± 5a , b |
| HR (bpm) | ||||
| Young | 58 ± 8 | 31 ± 18a | 61 ± 7 | 12 ± 6a |
| Middle aged | 55 ± 5 | 28 ± 15a | 57 ± 5 | 10 ± 5a |
| Old | 60 ± 6 | 21 ± 13a | 61 ± 7 | 10 ± 3a |
| CO (L·min−1) | ||||
| Young | 6.4 ± 0.9 | −7 ± 5a | 6.9 ± 0.8 | 11 ± 6a |
| Middle aged | 4.9 ± 0.7b | −6 ± 5a | 5.1 ± 0.8b | 9 ± 6a |
| Old | 4.7 ± 0.8b | −6 ± 5a | 4.8 ± 0.8b | 10 ± 3a |
| TPR (dyn·sec·cm−5) | ||||
| Young | 1142 ± 114 | 4 ± 5a | 1114 ± 112 | −3 ± 5 |
| Middle aged | 1601 ± 211b | −2 ± 7 | 1543 ± 208b | 1 ± 5 |
| Old | 1767 ± 350b | 2 ± 10 | 1747 ± 336b | 3 ± 5b |
| MCAVmean (cm·sec−1) | ||||
| Young | 72 ± 14 | −5 ± 5a | 72 ± 14 | 6 ± 6a |
| Middle aged | 59 ± 8b | −15 ± 7a , b | 57 ± 8b | 14 ± 14a |
| Old | 57 ± 15b | −11 ± 6a , b | 55 ± 14b | 14 ± 6a |
| CVRi (mmHg·cm−1·sec) | ||||
| Young | 1.30 ± 0.20 | 3 ± 5 | 1.35 ± 0.23 | 2 ± 6 |
| Middle aged | 1.66 ± 0.26b | 9 ± 9a | 1.73 ± 0.21b | −3 ± 10 |
| Old | 1.89 ± 0.57b | 9 ± 9a | 1.99 ± 0.56b | −1 ± 4 |
| PetCO2 (mmHg) | ||||
| Young | 41 ± 4 | −5 ± 4a | 40 ± 3 | −1 ± 3 |
| Middle aged | 41 ± 5 | −10 ± 6a , b | 40 ± 2 | 2 ± 5 |
| Old | 38 ± 6 | −14 ± 9a , b | 37 ± 4b , c | 5 ± 5a , b |
Data are presented as mean ± SD. TPR, total peripheral resistance; CVRi, cerebrovascular resistance index; BP, blood pressure; HR, heart rate; CO, cardiac output; MCAV, middle cerebral artery blood flow velocity; PetCO2, end‐tidal CO2 partial pressure.
a
P < 0.05 versus baseline.
b
P < 0.05 versus young.
c
P < 0.05 versus middle aged.