Abstract WP316: Submaximal Exercise Test to Predict VO2 Peak in Subacute Stroke
Purpose: Submaximal exercise testing can be an attractive alternative to peak testing especially in clinical environments where a metabolic cart and adequately trained medical staff may not be readily available. We examined the relationship between peak oxygen consumption (VO2 peak) and a predicted VO2 peak value obtained from a submaximal exercise test that we developed for a total body recumbent stepper (TBRS). We hypothesized that in people with subacute stroke, the actual VO2 peak and predicted VO2 peak would have a moderate (r > 0.75) relationship.
Methods: Ten individuals in the subacute stage of stroke recovery (68.6+40.1 days post-stroke) and 61.2+ 5.0 years of age participated in the study. Exercise testing using a metabolic cart and the TBRS for the exercise modality was performed on the first day to obtain VO2 peak. We used the Young Men’s Christian Association (YMCA) protocol for the TBRS. The step rate was maintained between 95-100 steps per minute (spm). Participants started the test at 30 watts and resistance was increased every 3 minutes according to the protocol until volitional fatigue, or 85% of age-predicted HR max was achieved. HR was recorded ten seconds prior to the end of the second and third minute of each stage. If the two HR measures were within 5 bpm of each other, participants progressed to the next stage. However, if the difference was greater than 5 bpm, an additional minute was performed to ensure a steady-state. The participants completed the submaximal exercise test within one to two days after the peak exercise test. The workload in watts and HR at the end of the submaximal exercise test along with age, sex and weight (kg) were used in the equation to predict VO2 peak.
Results: We found that predicted VO2 peak generated from the submaximal exercise test equation had a strong correlation to the actual VO2 peak (r = 0.80, p = 0.006). Mean peakVO2 (ml*kg-1*min-1) from the exercise test was 22.9 + 7.3 ml*kg-1*min-1 and the predicted mean value was 17.6 + 6.1 ml*kg-1*min-1. Paired t-test revealed a statistically significant difference between these two values (p = 0.005).
Conclusion: This preliminary data demonstrates the TBRS submaximal exercise test shows promise for assessing VO2 peak in sub-acute stroke.
- © 2012 by American Heart Association, Inc.