Understanding the potential contribution of a third "T" to FITT exercise prescription: the case of timing in exercise for obesity and cardiometabolic management in children.

Currently, exercise prescription relies heavily on parameters included in the FITT principle: frequency, intensity, time (duration), and type of exercise. In this paper, the benefits of including (FITT+T), referring to when exercise is performed in relation to meal-time, is discussed. Current research indicates that timing is outcome-specific. Total energy and lipid intakes, and postprandial hypertriglyceridemia can be reduced when exercise is performed pre-meal, while glycemic control is improved with post-meal exercise. Although findings indicate that timing can aid in obesity management and cardiometabolic-risk reduction, most research involves adult subjects and acute investigations. Some research with children, concerning the effect of timing on appetite, indicates that pre-meal exercise helps regulate energy balance, but also identifies key differences in response compared with adults. Overall, current findings support the benefits of timing, but research is required to establish guidelines that are specific to the pediatric population and their health-related goals, while incorporating other FITT components.