Elderly Cardiac Rehabilitation Patients Show Greater Improvements in Ventilation at Submaximal Levels of Exercise.
The minute ventilation (VE) and carbon dioxide output (VCO&sub2;) adaptations to 12 weeks of cardiac rehabilitation were investigated in diagnosis-matched elderly patients (ELD) and younger patients (YNG). Thirty ELD (25 males, 5 females; age equals 69.2Â+/-3.9 years) and 30 YNG (27 males, 3 females; age equals 48.3Â+/-7.0 years) were exercise tested at program entry (T1) and completion (T2). Peak oxygen uptake (VO&sub2; peak) and ventilatory threshold (VT) (ml kg-1 min-1) were greater for YNG at both T1 and T2 (p is less than 0.01). Both ELD and YNG showed significant T1 to T2 improvements (p is less than 0.01) for VO&sub2; peak (21.1% and 23.4%) and VT (20.1% and 12.4%). The VE/VCO&sub2; ratio was greater (p is less than 0.01) for ELD but approached YNG values after training. The VCO&sub2;/VO&sub2; slope showed a greater T1 to T2 reduction in ELD (12.4% vs 3.4%). There was no relationship (r(2) equals 0.15; NS) between the percentage change in VO&sub2; peak and VE/VCO&sub2; indicating unrelated mechanisms of improvement. We conclude that ELD showed similar improvements in VO&sub2; peak but greater improvements in their ventilatory tolerance for submaximal exercise. These changes indicate improvements in aging-enhanced exercise ventilation, are important for performance of normal activities of daily living, and would have been undetectable without gas exchange analysis.
McConnell
Timothy R.
TR
Geisinger Medical Center, Danville, PA.
Laubach
Charles A.
CA