Análise qualitativa dos critérios utilizados em experimentos para avaliação do equivalente metabólico de repouso em idosos: uma revisão sistemática

Abstract

Considering the importance of the resting metabolic equivalent (1-MET) for the area of exercise and sports and because contradictory data are observed in the literature regarding its value, especially in the elderly, when the standard value for 1-MET would be equivalent to a consumption of oxygen at rest (VO2) of 3.5 mL•kg-1•min-1 attributed to all populations, it becomes relevant to identify whether this contradiction is explained by differences inherent to the age group or by measurement problems, as several factors may alter resting VO2 during indirect calorimetry measurement. In addition, several protocols for its measurement were developed and the methodology used can also influence the test results. Therefore, the objective of this study was to evaluate the quality of the 1-MET measurements used in different studies carried out with the elderly, comparing them with the criteria recommended by Compher et al. (2006), published in the Academy of Nutrition and Dietetics Evidence Analysis Library. The registration protocol for this systematic review can be accessed on the PROSPERO website under number CRD42021267264. The systematic review followed the criteria recommended by PRISMA. Eligibility criteria for the studies were: Population (P): individuals of both sexes and age ≥ 65 years; Intervention/Interest (I): measurement of VO2 at rest by calorimetry; Comparison (C): not observed; Observation (O): Protocol for the assessment of VO2 at rest and mean values found; Study design (S): all types. There was no restriction regarding the year of publication and languages. The following databases were used: PubMed, Web of Science, Cochrane Library, Scopus and SPORTDiscus; in addition to manual searches. The search phrase was elaborated from the descriptors “Metabolic equivalent”, “Energy Metabolism”, “Basal Metabolism” and “Indirect Calorimetry”, taken from the Virtual Health Library (BVS), and their synonyms found in the Medical Subject Headings (MeSH), using the logical operators “AND” between the descriptors and “OR” between the synonyms. The “age” (≥65 years) and “species” (humans) filters were applied. The search performed generated a total of 1401 studies that initially went through the selection phase, in which 253 duplicate files were excluded. Subsequently, 152 studies were excluded by reading the titles and abstracts, totaling 996 studies in the eligibility phase, of which 906 studies were excluded for not meeting the inclusion criteria, leaving at the end 90 studies that were included in this review. Comparing the criteria of Compher et al. (2006) to those applied by the studies included in this review, in general terms, it was observed that only 15.5% met the ideal recommendations, while 84.4% did not, showing that it is possible that the problem pointed out is related to the inadequacy of the measures. Of the 90 studies selected for this review, only 14 met the recommendations, presenting mean values of 1-MET equal to 2.53 ± 0.5 mL•kg-¹•min-¹ (ranging from 0.89 to 3.30 mL • kg-¹• min-¹), while the other studies (76) that did not meet the recommendations showed a mean of 1-MET equal to 2.65 ± 0.53 mL•kg-¹•min-¹ (ranging from 0 .84 to 4.41 mL•kg -¹•min-¹). It is concluded that errors in the measurements may be generating the great variety in the values of 1-MET, generating uncertainties about the behavior of this variable in the elderly, since biological variables, different methods and methodologies used may be impacting the measurement values