Genes, exercise, growth, and the sedentary, obese child

Abstract

It is still not possible to provide an evidence-based answer to the question of whether regular exercise is essential for normal growth. It is also unclear whether very low levels of exercise result in growth deficits. Regular exposure to exercise is characterized by heterogeneity in responsiveness, with most individuals experiencing improvements in fitness traits but a significant proportion showing only very minor gains. Whether a sedentary mode of life during the growing years results in a permanent deficit in cardiorespiratory fitness or a diminished ability to respond favorably to regular exercise later in life remains to be investigated. Although several genes have been associated with fitness levels or response to regular exercise, the quality of the evidence is weak mainly because studies are statistically underpowered. The special case of the obese, sedentary child is discussed, and the importance of the "energy gap" in the excess weight gain during growth is highlighted. Obese, sedentary children have high blood pressure, dyslipidemia, elevated glycemia and type 2 diabetes, hepatic steatosis, respiratory problems, orthopedic complications, and other health disorders more frequently than normal weight, physically active children. The role of genetic differences in the inclination to be sedentary or physically active is reviewed. An understanding of the true role of genetic differences and regular exercise on the growth of children will require more elaborate paradigms incorporating not only DNA sequence variants and exercise exposure but also information on nutrition, programming, and epigenetic events during fetal life and early postnatal years.

The biological control of voluntary exercise, spontaneous physical activity and daily energy expenditure in relation to obesity: human and rodent perspectives

“…Although none of the 1.6 million single nucleotide polymorphisms (SNPs) reached genome-wide significance, SNPs in three genomic regions showed suggestive significance levels (see Rankinen et al, 2010). Studies of genetic polymorphisms associated with performance-related phenotypes (as opposed to measures of how much they engage in physical activity) are more numerous and reviewed elsewhere (Teran-Garcia et al, 2008;Rankinen et al, 2010).…”

Individual Genetic Variations Related to Satiety and Appetite Control Increase Risk of Obesity in Preschool-Age Children in the STRONG Kids Program

“…The STRONG Kids program was developed under an ecological framework with several spheres of influence that we termed the 6Cs model: cell, child, clan, community, country, and culture [10] . The effects of these environmental factors and their interactions on the onset of childhood obesity and the sphere of biological influence ('the Cell'), which encompasses the genetic and metabolic individuality that affects the risk of diseases associated with childhood obesity, were studied [11] .…”

Exercise and diet affect quantitative trait loci for body weight and composition traits in an advanced intercross population of mice

“…With regard to exercise, it has long been known that physical activity of various kinds tends to decrease the probability of obesity and associated health problems such as various cancers (3,6,8,53). Yet this trend is not always clear, and there typically is considerable variability in the extent of weight loss even among individuals who routinely engage in exercise (25,30,60).…”