Background/Aims
Cardiopulmonary exercise testing (CPET) has not previously been studied in people with class 3 obesity (BMI ≥40kg/m2) and type 2 diabetes (T2DM), where equipment and exercise protocols may need modification to accommodate body size and exercise tolerance. The aim of this study was to determine the ability to assess cardiorespiratory fitness with a modified exercise protocol among individuals with class 3 obesity/T2DM.
Methods
This was an open-label cohort study with T2DM and class 3 obesity enrolled in a publicly funded multidisciplinary metabolic program in Sydney where all patients were offered supervised exercise classes 1-2 times a week, but attendance was optional. CPET was performed at baseline and after 12 weeks, including maximal progressive exercise protocol on cycle ergometry to determine first ventilatory threshold (VT1, when participant respiratory rate starts to increase), second ventilatory threshold (VT2, when participants start to breath heavily), anaerobic threshold (AT), peak power and peak oxygen uptake (VO2).
Results
Of 17 participants, only 13 (76%) were able to start the exercise protocol. Data is presented here for n=10 who had baseline and 12-week follow-up data. Participants were 80% female, aged 52±12 years, baseline weight 127.3±34.9kg and BMI 48.14±7.49kg/m². After 12 weeks, mean weight loss was 2.84±5.8kg. There was no significant change between mean VT1 from baseline 0.96±0.25(L/min) to 12 weeks 0.95±0.31(L/min). Only 40% (n=4) were able to exercise until they reached VT2 at baseline, mostly due to pain and discomfort during exercise, which increased to 70% (n=7) at 12 weeks. There was no change from baseline to 12 weeks in AT [0.92±0.23(L/min) to 0.98±0.35(L/min), p=0.35], peak VO2 [1.56±0.55(L/min) to 1.59±0.56(L/min), p=0.55], or peak Power [71±30 Watts to 77±25 Watts, p=0.19].
Conclusions
Current protocols for CPET need to be further modified to accommodate the needs and fitness of people with class 3 obesity and T2DM.