This is a response to commentary by Jiménez-Pavon (2015) on the relationships of leptin levels with children’s physical activity. The present response suggests actigraphs are superior to questionnaires for measuring children’s physical activity. Cicchella, Stefanelli, Jurimae, Saar and Purge (2013) pointed out some interesting methodological issues related to the relationships of leptin and physical activity in normal weight children. The questions dealt with the reliability of the questionnaires in assessing physical activity in children, choices of the cut-off points for considering levels of physical activity as moderate or intense, and the association of leptin with PA levels. Some considerations in Jiménez-Pavon (2015) remain unclear.