Research from JAMA Pediatrics — Metabolic and Physiologic Responses to Video Game Play in 7- to 10-Year-Old Boys

A sexual dimorphism exists in which increased abdominal and visceral adipose tissue (VAT) – found in women and marked by low sex hormone binding globulin (SHBG) and high bioavailable testosterone (BT) – is related to the metabolic risk profile. In men, increased BT is related to decreased abdominal obesity and a decrease in the metabolic risk profile. In women, race differences have been found in androgenic sex steroids including SHBG and BT as well as central fat distribution, creating inherently greater metabolic risk for certain populations. Estrogen and estrogen receptor isoforms play a role in fat deposition and distribution and may influence the changes that occur during the menopausal transition. Androgenic sex steroids serve a mediating role, influencing VAT accumulation and its associated metabolic risk factors while VAT also serves a mediating role influencing the androgenic sex steroid-metabolic risk relationship in women. Furthermore, androgenic sex steroids and VAT may independently contribute to the variance in several metabolic variables associated with cardiovascular disease, type 2 diabetes, and their antecedent conditions such as the metabolic syndrome. Race has been shown to modify the relationship between androgenic sex steroids and metabolic variables associated with risk for diabetes in Black and White women. Further research is warranted to examine the mechanisms involved in race differences. Total adiposity and central fat distribution in accordance with changes in the hormone and metabolic milieu influence breast cancer risk, which varies by race and menopausal status. These findings have broader implications for the study of health promotion/disease prevention in women.

Body Dissatisfaction (BD) and low physical self-concept and exercise efficacy have been linked to poor physical fitness levels and adverse health outcomes in children. The purpose of this study was to examine the relationship between BD, physical fitness, exercise self-efficacy, and self-Perception of Physical Fitness (PFP) in Latina and Black female children. Twenty-eight Latina and Black children enrolled in an elementary afterschool program, aged 8–12, completed surveys evaluating body dissatisfaction, exercise efficacy, PFP, and measures of physical fitness. Subjects exhibited moderate but significant inverse relationships between BD and PFP in strength (r = −0.459), agility (r = −0.382), aerobic fitness (r = −0.354), and flexibility (r = −0.461) (p < 0.05 for all). There was a significant negative correlation between exercise efficacy and BD (r = −4.2; p < 0.05). Power (r = 0.51) and flexibility (r = 0.42) were the only physical fitness measures significantly and positively related to children’s PFP (p < 0.05). A significant medium inverse relationship was also found between BD and aerobic fitness scores (r = −0.381; p < 0.05). However, after controlling for exercise efficacy or perception of physical fitness, the relationship between BD and aerobic fitness was not significant (p > 0.05). Findings suggest that positive PFP and positive performance in several physical fitness measures are associated with lower levels of BD in minority female children. Furthermore, evidence suggests exercise efficacy and PFP can mediate the relationship body image and aerobic fitness. These findings suggest that PFP, more so than measured physical fitness, was associated with lower levels of BD in minority female children. These results have important implications for programs designed to improve physical fitness and mental health in minority children.

Objective: To determine the independent contribution of androgenic sex hormones beyond visceral adipose tissue (VAT) on metabolic risk.Design and Methods: A cross‐sectional evaluation of 66 (36 white and 30 black) premenopausal overweight/obese women using multiple regression analyses to determine the independent effects of sex hormone‐binding globulin (SHBG), total testosterone (TT), and free testosterone using the free androgen index (FAI) on metabolic variables above VAT.Results: SHBG contributed to the variance in insulin (P = 0.003), insulin resistance using HOMA‐IR (P = 0.006), and high‐density lipoprotein cholesterol₂ (P = 0.029). TT contributed to the variance in systolic and diastolic blood pressure (P < 0.001), total cholesterol (P = 0.003), low‐density lipoprotein cholesterol (P = 0.003), and apolipoprotein B (P = 0.004). FAI contributed to the variance in the greatest number of metabolic variables beyond VAT. There was also a significant race–FAI interaction for fasting glucose (P = 0.013). A Pearson's correlation coefficient showed a significant relationship between FAI and glucose in white women (r = 0.48, P = 0.003) while showing no relationship in black women (r = −0.01, P = 0.941).Conclusions: Our study showed that androgenic sex steroids contributed significantly to the variance in metabolic variables associated with health risk. However, they do not provide sufficient information relevant to glucose status in black women.

The mechanisms through which exercise reduces cardiovascular disease are not fully understood. We used echocardiograms, cardiac biomarkers and gene expression to investigate cardiovascular effects associated with exercise training.