Barnard R J, MacAlpin R, Kattus A A, Buckberg G D
Circulation. 1977 Aug;56(2):289-91. doi: 10.1161/01.cir.56.2.289.
In five well-trained and five sedentary control subjects potential subendocardial blood supply was estimated from the diastolic pressure time index (DPTI) and myocardial oxygen demands from the tension time index (TII) during a progressive near-maximal treadmill test. DPTI/TTi was used to assess the effects of training on myocardial oxygen supply/demand balance. DPTI/TTI was significantly higher in trained subjects at rest and comparable workloads. At 6.4 km/hr, 18% grade (maximum for the controls), TTI was significantly lower (4300 +/- 76 vs 4495 +/- 99 mm Hg-sec/min) and DPTI significantly higher (2534 +/- 86 vs 2295 +/- 91 mm Hg-sec/min) in the trained subjects; DPTI/TTI was significantly higher (0.59 +/- .02 vs 0.50 vs .03). At near-maximal heart rates both groups achieved the same supply/demand balance (0.50); however, the trained subjects were working at higher workloads. We conclude that endurance conditioning increases work capacity, reduces myocardial O2 demands, increases potential O2 supply and improves the supply/demand balance at any given submaximal workload which reduces the risk of ischemia.
在5名训练有素的受试者和5名久坐不动的对照受试者中，在递增的接近最大强度的跑步机测试期间，根据舒张压时间指数（DPTI）估算潜在的心内膜下血液供应，根据张力时间指数（TII）估算心肌需氧量。DPTI/TII用于评估训练对心肌氧供需平衡的影响。在静息状态和相当的工作量下，训练有素的受试者的DPTI/TII显著更高。在6.4公里/小时、18%坡度（对照组的最大坡度）时，训练有素的受试者的TII显著更低（4300±76对4495±99毫米汞柱-秒/分钟），DPTI显著更高（2534±86对2295±91毫米汞柱-秒/分钟）；DPTI/TII显著更高（0.59±0.02对0.50±0.03）。在接近最大心率时，两组达到相同的供需平衡（0.50）；然而，训练有素的受试者在更高的工作量下工作。我们得出结论，耐力训练可提高工作能力，降低心肌需氧量，增加潜在的氧供应，并在任何给定的次最大工作量下改善供需平衡，从而降低缺血风险。
