Sedentary Lifestyle: Physical Activity Duration Versus Percentage of Energy Expenditure

Introduction and objectivesTo compare different definitions of a sedentary lifestyle and to determine which is the most appropriate for demonstrating its relationship with the metabolic syndrome and other cardiovascular risk factors.MethodsA cross-sectional study of 5814 individuals was carried out. Comparisons were made between two definitions of a sedentary lifestyle: one based on active energy expenditure being less than 10% of total energy expenditure, and the other, on performing less than 25–30 minutes of physical activity per day. Reported levels of physical activity, anthropometric measurements, and biochemical markers of cardiovascular risk were recorded. The associations between a sedentary lifestyle and metabolic syndrome and other risk factors were adjusted for gender, age and tobacco use.ResultsThe prevalence of a sedentary lifestyle was higher in women (70%) than in men (45%–60%, according to the definition used). The definitions based on physical activity duration and on energy expenditure were equally useful: there were direct associations between a sedentary lifestyle and metabolic syndrome, body mass index, abdominal and pelvic circumferences, systolic blood pressure, heart rate, apolipoprotein B, and triglycerides, and inverse associations with high-density lipoprotein cholesterol and paraoxonase activity, which demonstrated the greatest percentage difference between sedentary and active individuals. An incidental finding was that both definitions of a sedentary lifestyle were more strongly associated with the metabolic syndrome as defined by International Diabetes Federation criteria than by Adult Treatment Panel III criteria.ConclusionsGiven that it is relatively easy to determine whether a patient performs less than 25 minutes of physical activity per day, use of this definition of a sedentary lifestyle is recommended for clinical practice. The serum paraoxonase activity level could provide a useful marker for studying sedentary lifestyles.

Introducción y objetivosComparar 2 definiciones diferentes de sedentarismo y averiguar cuál es más efectiva para detectar su relación con el síndrome metabólico (SM) y otros factores de riesgo cardiovascular.MétodosEstudio transversal de 5.814 individuos. Se compara el concepto de sedentarismo basado en consumir activamente menos del 10% del gasto energético total con el concepto basado en no realizar al menos 25–30 min diarios de ocio activo. Se analizan la actividad física declarada, la antropometría y los marcadores bioquímicos de riesgo cardiovascular. La relación del sedentarismo con el SM y los marcadores de riesgo se ajustó por el sexo, la edad y el tabaquismo.ResultadosLa prevalencia de sedentarismo en mujeres (70%) fue superior a la de los varones (un 45–60%, según el concepto empleado). El tiempo de ocio mostró la misma efectividad que la energía consumida: el sedentarismo se asoció directamente con el SM, el índice de masa corporal, las cinturas abdominal y pélvica, la presión arterial sistólica, la frecuencia cardiaca, la apolipoproteína B y los triglicéridos, e inversamente con el colesterol unido a lipoproteínas de alta densidad (cHDL) y la actividad de la paraoxonasa (ésta presentó el mayor porcentaje de variación entre sedentarios y activos). Como resultado colateral se obtuvo que la definición de SM propuesta por la Federación Internacional de Diabetes se asocia con mayor fuerza que la del ATP-III a cualquier concepto de sedentarismo.ConclusionesDada su mayor facilidad de obtención, en la práctica clínica es recomendable el uso del concepto de sedentarismo basado en averiguar si el paciente realiza al menos 25 min diarios de ocio activo. La actividad de la paraoxonasa es un marcador de interés para el estudio del sedentarismo.