Table 2.

Cardiovascular variability during active squat-stand maneuvers in young and elderly subjects

Variables	Young, n = 10		Elderly, n = 8
	0.1 Hz	0.05 Hz	0.1 Hz	0.05 Hz
SBP, mmHg	134±15	129±15	170±28*	153±27*
DBP, mmHg	67±12	67±10	75±8	70±9
HR, beats/min	88±17	82±17	92±14	88±15
RF, Hz	0.37±0.05	0.37±0.06	0.38±0.12	0.37±0.13
ETCO2, mmHg	38±5	36±4	40±3	38±4
SBP-SP, mmHg2	253±119	374±191	203±87	561±321†
RR-SP, ms2	8075±8930	24839±13829†	497±677	3098±3726*
Gain, ms/mmHg	5.4±2.9	7.6±2.8†	1.2±1.0*	2.2±2.1*
Gain-P, ms/mmHg	5.3±2.9	8.6±3.4†	1.1±0.8*	2.1±2.2*
Phase, rads	−0.8±0.3	−0.5±0.2	−1.6±0.7*	−1.3±0.5*†
Phase-P, rads	−0.8±0.3	−0.4±0.2†	−1.7±0.6*	−1.2±0.5*†
Coherence	0.82±0.07	0.79±0.08	0.69±0.15	0.72±0.16
Coherence-P	0.97±0.03	0.98±0.01	0.89±0.14	0.92±0.08†

Values are means ± SD. Transfer function gain, phase, and coherence were estimated in the frequency range from 0.078 to 0.125 Hz and from 0.031 to 0.078 Hz. Gain-P, Phase-P, and Coherence-P were estimated at the peak coherence.

^*P < 0.05, comparisons between young and elderly at the same frequency.

^†P < 0.05, comparisons between the frequencies for the same group.