1. Faber, Matthew J. MS

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The Bruce treadmill protocol (BR) is the most widely used clinical exercise protocol. However, the high starting workload and large changes between stages make BR less than optimal for older & more debilitated patients. Despite this limitation, physicians are widely familiar with BR, and it is still widely used. Several modifications (M) of BR have been developed, but none maintain the net rate of workload incrementation, which is critical for physician acceptance, while starting lower and having smaller differences between stages.



This study was designed to compare exercise responses to BR & MBR, to test the hypothesis that MBR would be physiologically equivalent to BR, but have better patient acceptance.



Volunteer subjects (age 21-72) (n = 22) performed a habituation treadmill test and then randomly ordered BR & MBR, all with concurrent measurement of respiratory gas exchange. The starting point of MBR was lower (1.4 mph, 0%grade), and the workload changed every minute, but the speed & grade were equivalent to BR during every 3rd min.



Exercise responses were generally of similar magnitude and well related between MBR vs BR. Treadmill time was longer for MBR (P <.05) (10.2 +/- 2.9 vs 9.5 +/- 2.8 min; R2 = 0.94), however there were no differences in VO2max (29.5 +/- 9.9 vs 30.3 +/- 10.4 ml/kg; R2 = 0.95), HRmax (169 +/- 27 vs 172 +/- 29 bpm; R2 = 0.87), RPP (29.4 +/- 5.6 vs 28.9 +/- 6.9 *103; R2 = 0.77), VEmax (83 +/- 29 vs 88 +/- 31 L/min; R2 = 0.91). Most (20 of 22; 91%) of the subjects preferred MBR.



The MBR allows provocation of similar physiologic responses, with only a minimally different time requirement, and a strong subject preference. As such it may provide a convenient alternative to BR, with comparable physician acceptance and better patient tolerability.