The neurorehabilitation device Equistasi® impacts positively on the gait of Parkinson's disease subjects (original) (raw)

Table 1 Directly measured and estimated oxygen consumption (VO2) are displayed for each type of training (aerobic and isotonic) * indicates a significant difference vs measured VO2 and • a significant difference vs aerobic training. Training type Measured VO2 (ml/min) Estimated VO2 (ml/min) AEROBIC 1368,96 1397,83 ISOTONIC 667,03 • 910,96 • * combination with isotonic/strength training (50 to 70% of 1RM). Accurate quantification and monitoring of exercise "dose", as described by VO 2 , is necessary for appropriate and individualised prescription of aerobic exercise and for the interpretation of exercise-induced health benefits (Gaber, 2011). However, due to the elevated cost of direct, gold-standard methods, this is rarely done outside research laboratories. HR index (HR index) is a simple method to estimate VO 2 in healthy and clinical populations. We tested the performance of HR index to estimate VO 2 in diabetic patients during aerobic and isotonic training sessions. Methods: 12 male subjects (age: 64 ± 5 years; BMI: 26 ± 12) with uncomplicated T2DM on oral hypoglycemic drugs were recruited. VO 2 consumption and HR were continuously measured (K4, Cosmed, Italy) during one aerobic and one isotonic training session, each lasting 60 min. Individual HR index was calculated as actual HR/resting HR and the following equation was applied to estimate average VO 2 for both training sessions 2 : VO 2 (L/min) = {[(HR index •6)-5] • (3.5 body weight (Kg))} (Wicks, 2011). Correspondence between measured and estimated VO 2 was evaluated by two-way ANOVA (method of determination and training type) and correlation. Results: Measured VO 2 was higher for the aerobic compared to the isotonic training session (Table 1). Estimated values of VO 2 during the aerobic session were not significantly different from (p = 0.36) and highly correlated (r = 0.89) with the measured values. On the contrary, during the isotonic session, HR index significantly overestimated VO 2 compared to the actual measure and only a moderate correlation was found between measured and estimated values (r = 0.41). Discussion: We tested the performance of HR index in predicting oxygen consumption (VO 2) in a group of diabetic patients during aerobic and isotonic training sessions, by comparison with the gold standard direct method. Our data indicate that HR index significantly overestimates VO 2 during isotonic exercise, possibly due to the dissociation between HR and VO 2 that is inherent to this form of exercise. On the contrary, our data support the hypothesis that HR index is a valid tool to estimate VO 2 of prolonged aerobic exercise sessions in diabetic patients. This simple approach offers a valid alternative to the high "cost" (equipment, time, expertise) gold-standard measurement of VO 2 favouring the generalised applicability of measures of exercise "dose". The knowledge of population-specific dose-response curves is paramount to guide personalised and evidence-based exercise prescription.