Breastfeeding has been associated with a protective effect against cardiovascular disease in childhood which, in turn, is associated with a healthier cardiovascular profile later in life.

A study was carried out in Estonia and Sweden to examine the association of exclusive breastfeeding duration with fitness in children and adolescents and to test the role of body composition and sociodemographic factors in this relation. Exclusive breastfeeding duration was reported by mothers of 1,025 children (aged 9.5 ± 0.4 years) and 971 adolescents (aged 15.5 ± 0.5 years) grouped into 4 categories: exclusively formula-fed or breastfed for <3, 3–6, or >6 months. Fitness was determined by a maximal cycle-ergometer test.

The researchers found that longer duration of breastfeeding was associated with higher fitness regardless of confounders. The results were consistent regardless of birthweight, and in non-overweight or overweight children and adolescents, in offspring of non-overweight or overweight mothers, and in mothers with a low or high educational level.

They conclude that because longer exclusive breastfeeding has a beneficial effect on cardiorespiratory fitness in children and adolescents, further work to better understand the possible programming effect of exclusive breastfeeding on cardiorespiratory fitness is of public health interest.

Labayen I, Ruiz JR, Ortega FB et al (2012) Exclusive breastfeeding duration and cardiorespiratory fitness in children and adolescents. Am J Clin Nutr. published 11 January 2012, 10.3945/ajcn.111.023838