The Assessment Of Correct Exercise Intensities In Tailored Exercise Prescription: Are Indirect Formulae Enough?

Exercise prescription includes aerobic, resistance and flexibility training and follows the Frequency Intensity Time Type - Volume Progression model. In this model, definition of aerobic exercise intensity (EI) is crucial to define overall training program, to maximize beneficial effect and to reduce potential risks. The gold standard for assessing EI is using ventilatory thresholds (VTs) obtained by cardiopulmonary exercise testing (CPET). If it is unavailable, different indirect formulae can be used, such as percentage of peak of oxygen consumption (VO2), maximal heart rate (HR) or heart rate reserve (HRR). PURPOSE: to verify if the indirect methods are appropriate for prescribing EI in patients with different chronic disease, such as obesity (Ob), patients underwent kidney transplantation (KTR) and adult-patients with surgically well-repair aortic coartaction (CoA). METHODS: 713 patients were evaluated with CPET. Percentages of VO2 peak at CPET, maximal HR (measured and calculated) and HRR (measured and calculated), obtained at first and second VTs, were compared with the EI domains (moderate and high, respectively) using a sensitivity analysis. RESULTS: Higher sensitivity values in different diseases are often low in absolute values, varying from 55% to 65%. Moderate EI domain seems to be easier to identify with indirect formulae, reaching a sensitivity of 80% in KRTs and 94% in adults with CoA. Sometimes sensitivity is lower than 20%, especially with %HRR calculated formula. (Table I) CONCLUSIONS: The indirect range-based methods seem not to be always appropriate to prescribe correct exercise intensity training. In patients with different chronic disease, the identification of ventilatory thresholds by CPET remains essential for determining correct EI domains. - Table I Obesity N = 462 Kidney Transplant Recipients N = 178 Aortic Coartaction N = 73 Moderate intensity High intensity Moderate intensity High intensity Moderate intensity High intensity %VO2peak measured 0.65(0.61-0.69) 0.49(0.45-0.54) 0.80(0.74-0.86) 0.61(0.53-0.68) 0.94(0.89-0.99) 0.56(0.45-0.68) %HRmax measured 0.28*(0.24-0.32) 0.45*(0.41-0.50) 0.49*(0.42-0.56) 0.56(0.48-0.63) 0.85(0.77-0.93) 0.58(0.46-0.69) %HRmax calculated 0.61(0.57-0.65) 0.55(0.51-0.60) 0.58*(0.51-0.65) 0.35*(0.28-0.42) 0.71*(0.61-0.82) 0.59(0.48-0.70) %HRR measured 0.65(0.61-0.69) 0.43*(0.38-0.47) 0.38*(0.31-0.45) 0.33*(0.26-0.40) 0.81*(0.72-0.90) 0.40*(0.29-0.51) %HRR calculated 0.47*(0.43-0.52) 0.20*(0.16-0.24) 0.16*(0.11-0.22) 0.10*(0.06-0.15) 0.60*(0.49-0.71) 0.45(0.34-0.57) Sensitivity (IC 95%) of relative methods for determining “moderate” and “high” exercise intensity domains. *p < 0.05 when compared with best formula for same EI domain in the same population.