Aging attenuates the coronary blood flow response to cold air breathing and isometric handgrip in healthy humans

作者：Muller Matthew D; Gao Zhaohui; Mast Jessica L; Blaha Cheryl A; Drew Rachel C; Leuenberger Urs A; Sinoway Lawrence I^*

来源：American Journal of Physiology - Heart and Circulatory Physiology, 2012, 302(8): H1737-H1746.

DOI：10.1152/ajpheart.01195.2011

• blood pressure
• heart rate
• sympathetic nervous system
• oxygen consumption
• tissue Doppler imaging

Muller MD, Gao Z, Mast JL, Blaha CA, Drew RC, Leuenberger UA, Sinoway LI. Aging attenuates the coronary blood flow response to cold air breathing and isometric handgrip in healthy humans. Am J Physiol Heart Circ Physiol 302: H1737-H1746, 2012. First published February 17, 2012; doi: 10.1152/ajpheart.01195.2011.-The purpose of this echocardiography study was to measure peak coronary blood flow velocity (CBVpeak) and left ventricular via tissue Doppler imaging) during separate and combined bouts of cold air inhalation (-14 +/- 3 degrees C) and isometric handgrip (30% maximum voluntary contraction). Thirteen young adults and thirteen older adults volunteered to participate in this study and underwent echocardiographic examination in the left lateral position. Cold air inhalation was 5 min in duration, and isometric handgrip (grip protocol) was 2 min in duration; a combined stimulus (cold + grip protocol) and a cold pressor test (hand in 1 degrees C water) were also performed. Heart rate, blood pressure, O-2 saturation, and inspired air temperature were monitored on a beat-by-beat basis. The rate-pressure product (RPP) was used as an index of myocardial O-2 demand, and CBVpeak was used as an index of myocardial O-2 supply. The RPP response to the grip protocol was significantly blunted in older subjects (Delta 1,964 +/- 396 beats.min(-1).mmHg) compared with young subjects (Delta 3,898 +/- 452 beats.min(-1).mmHg), and the change in CBVpeak was also blunted (Delta 6.3 +/- 1.2 vs. 11.2 +/- 2.0 cm/s). Paired t-tests showed that older subjects had a greater change in the RPP during the cold + grip protocol [Delta 2,697 +/- 391 beats.min(-1).mmHg compared with the grip protocol alone (Delta 2,115 +/- 375 beats.min(-1).mmHg)]. An accentuated RPP response to the cold + grip protocol (compared with the grip protocol alone) without a concomitant increase in CBVpeak may suggest a dissociation between the O-2 supply and demand in the coronary circulation. In conclusion, older adults have blunted coronary blood flow responses to isometric exercise.

• 出版日期2012-4