Is willingness to exercise programmed in utero? Reviewing sedentary behavior and the benefits of physical activity in intrauterine growth restricted individuals / A vontade de se exercitar é programada ainda no útero? Análise do comportamento sedentário e dos benefícios da atividade física em indivíduos com crescimento intrauterino restrito

Abstract Objective: The literature suggests that a fetus will adapt to surrounding adversities by optimizing its use of energy to improve survival, ultimately leading to the programming of the individual's energy intake and expenditure. While recent reviews focused on the fetal programming of energy intake and food preferences, there is also some evidence that fetal adversity is associated with diminished physical activity levels. Therefore, we aimed to review (a) the evidence for an association between being born with intrauterine growth restriction and sedentarism over the life-course and (b) the potential benefits of physical activity over cardiometabolic risk factors for this population. Sources: PubMed, Scielo, Scopus and Embase. Summary of findings: Most clinical studies that used objective measures found no association between intrauterine growth restriction and physical activity levels, while most studies that used self-reported questionnaires revealed such relationships, particularly leisure time physical activity. Experimental studies support the existence of fetal programming of physical activity, and show that exposure to exercise during IUGR individuals' life improves metabolic outcomes but less effect was seen on muscle architecture or function. Conclusions: Alterations in muscle strength and metabolism, as well as altered aerobic performance, may predispose IUGR individuals to be spontaneously less physically active, suggesting that this population may be an important target for preventive interventions. Although very heterogeneous, the different studies allow us to infer that physical activity may have beneficial effects especially for individuals that are more vulnerable to metabolic modifications such as those with IUGR.

Resumo Objetivo: A literatura sugere que um feto se adaptará às adversidades externas ao aprimorar seu gasto energético para melhorar a sobrevida, o que leva, em última instância, à programação do consumo e gasto energético do indivíduo. Apesar de análises recentes terem focado na programação fetal do consumo energético e preferências alimentares, ainda há alguma comprovação de que as adversidades fetais estão associadas aos baixos níveis de atividade física. Portanto, visamos a analisar: a) a comprovação de uma associação entre nascer com restrição de crescimento intrauterino (RCIU) e sedentarismo durante o curso de vida e b) os possíveis benefícios da atividade física sobre os fatores de risco cardiometabólico dessa população. Fontes: PubMed, Scielo, Scopus e Embase. Resumo dos achados: A maior parte dos estudos clínicos que usaram medidas objetivas não constatou associação entre RCIU e os níveis de atividade física, ao passo que a maior parte dos estudos que usaram questionários de autorrelato revelou essas relações, principalmente no que diz respeito à atividade física de lazer. Estudos experimentais corroboram a existência de programação fetal de atividade física e mostram que a exposição a exercícios durante a vida de indivíduos com RCIU melhora os resultados metabólicos, porém menos efeito foi visto sobre a arquitetura ou função muscular. Conclusões: Alterações na força muscular e no metabolismo, bem como o desempenho aeróbico alterado, podem predispor indivíduos com RCIU a serem espontaneamente menos ativos fisicamente, sugere que essa população pode ser um importante alvo de intervenções preventivas. Apesar de muito heterogêneos, os diferentes estudos nos possibilitam deduzir que a atividade física pode ter efeitos benéficos principalmente em indivíduos mais vulneráveis a modificações metabólicas, como aqueles com RCIU.

Is willingness to exercise programmed in utero? Reviewing sedentary behavior and the benefits of physical activity in intrauterine growth restricted individuals.

OBJECTIVE: The literature suggests that a fetus will adapt to surrounding adversities by optimizing its use of energy to improve survival, ultimately leading to the programming of the individual's energy intake and expenditure. While recent reviews focused on the fetal programming of energy intake and food preferences, there is also some evidence that fetal adversity is associated with diminished physical activity levels. Therefore, we aimed to review (a) the evidence for an association between being born with intrauterine growth restriction and sedentarism over the life-course and (b) the potential benefits of physical activity over cardiometabolic risk factors for this population. SOURCES: PubMed, Scielo, Scopus and Embase. SUMMARY OF FINDINGS: Most clinical studies that used objective measures found no association between intrauterine growth restriction and physical activity levels, while most studies that used self-reported questionnaires revealed such relationships, particularly leisure time physical activity. Experimental studies support the existence of fetal programming of physical activity, and show that exposure to exercise during IUGR individuals' life improves metabolic outcomes but less effect was seen on muscle architecture or function. CONCLUSIONS: Alterations in muscle strength and metabolism, as well as altered aerobic performance, may predispose IUGR individuals to be spontaneously less physically active, suggesting that this population may be an important target for preventive interventions. Although very heterogeneous, the different studies allow us to infer that physical activity may have beneficial effects especially for individuals that are more vulnerable to metabolic modifications such as those with IUGR.

Both food restriction and high-fat diet during gestation induce low birth weight and altered physical activity in adult rat offspring: the "Similarities in the Inequalities" model.

We have previously described a theoretical model in humans, called "Similarities in the Inequalities", in which extremely unequal social backgrounds coexist in a complex scenario promoting similar health outcomes in adulthood. Based on the potential applicability of and to further explore the "similarities in the inequalities" phenomenon, this study used a rat model to investigate the effect of different nutritional backgrounds during gestation on the willingness of offspring to engage in physical activity in adulthood. Sprague-Dawley rats were time mated and randomly allocated to one of three dietary groups: Control (Adlib), receiving standard laboratory chow ad libitum; 50% food restricted (FR), receiving 50% of the ad libitum-fed dam's habitual intake; or high-fat diet (HF), receiving a diet containing 23% fat. The diets were provided from day 10 of pregnancy until weaning. Within 24 hours of birth, pups were cross-fostered to other dams, forming the following groups: Adlib_Adlib, FR_Adlib, and HF_Adlib. Maternal chow consumption and weight gain, and offspring birth weight, growth, physical activity (one week of free exercise in running wheels), abdominal adiposity and biochemical data were evaluated. Western blot was performed to assess D2 receptors in the dorsal striatum. The "similarities in the inequalities" effect was observed on birth weight (both FR and HF groups were smaller than the Adlib group at birth) and physical activity (both FR_Adlib and HF_Adlib groups were different from the Adlib_Adlib group, with less active males and more active females). Our findings contribute to the view that health inequalities in fetal life may program the health outcomes manifested in offspring adult life (such as altered physical activity and metabolic parameters), probably through different biological mechanisms.