Physical Activity Is Associated with Attention Capacity in Adolescents

OBJECTIVE

To assess the relationships among physical activity, measured objectively, and attention capacity in European adolescents.

STUDY DESIGN

The study included 273 adolescents, aged 12.5-17.5 years, who participated in the Healthy Lifestyle in Europe by Nutrition in Adolescence Study. Participants wore a uniaxial accelerometer for 7 days to measure physical activity. The d2 Test of Attention was administered to assess attention capacity. Multivariate analyses were used to study the association of attention capacity with each measure of physical activity. Receiver operating characteristic analysis was performed to determine thresholds that best discriminate between low and good attention capacity.

RESULTS

After controlling for potential confounding variables (age, sex, body mass index, parental educational level, fat mass, aerobic fitness, and center), adolescents' attention capacity test performances were significantly and positively associated with longer time spent in moderate or moderate-to-vigorous physical activity (MVPA) in free-living conditions (P < .05). Receiver operating characteristic curve analyses revealed that the physical activity thresholds that best discriminated between low/good attention capacities were ≥41 min·day(-1) for moderate, ≥12 min·day(-1) for vigorous, and ≥58 min·day(-1) for MVPA.

CONCLUSION

These findings suggest that promoting MVPA may be have a beneficial effect on attention capacity, an important component of cognition, in adolescents.

Physical activity and markers of insulin resistance in adolescents: role of cardiorespiratory fitness levels--the HELENA study

OBJECTIVE

To analyze the association between objectively assessed physical activity (PA) and markers of insulin resistance (IR) in European adolescents and to examine whether the association of objectively assessed PA and markers of IR is modified by cardiorespiratory fitness (CRF).

METHODS

A cross-sectional study at school setting was conducted in 1053 (554 girls) adolescents (12.5-17.5 yr). Weight, height, waist circumference, total body fat, PA (accelerometry), and CRF (20-m shuttle run test) were measured. Fasting insulin and glucose concentrations were measured, and homeostasis model assessment as well as quantitative insulin sensitivity check index were computed.

RESULTS

In males, vigorous PA (VPA) was negatively associated with markers of IR after adjusting for confounders including waist circumference (all p < 0.05). In females, moderate PA, moderate to vigorous PA, and average PA were negatively associated with markers of IR after adjusting for confounders (all p < 0.05). Moreover, when the sample was segmented by CRF levels all the PA intensities were significantly associated with the markers of IR in females with low CRF but not in those with middle-high CRF after adjusting for confounders.

CONCLUSIONS

The findings suggest that PA is negatively associated with markers of IR after adjusting for confounders including total and central body fat in both sexes, but this relationship is modified by the CRF levels being especially important in those females with low CRF. Preventive strategies should focus not only on increasing the volume of PA but also on enhancing CRF through VPA.

Health-related physical fitness according to chronological and biological age in adolescents. The AVENA study

AIM

Physical fitness has been proposed as a major marker of health status at any age. The aim of the present study was to determine the levels of several health-related physical fitness components with respect to chronological and biological age (sexual maturation status) in Spanish adolescents.

METHODS

Physical fitness was measured in a sample of Spanish adolescents (N. = 2859; 1357 males, 1502 females) from the AVENA study, by means of the following tests: sit and reach, handgrip, standing broad jump, bent arm hang, 4 x 10 m shuttle run, and 20 m shuttle run. Percentage body fat, fat free mass and leisure-time physical activity were used as confounders. Adolescents were classified according to chronological age and biological age (measured by Tanner stages). All the analyses were adjusted for the above- mentioned confounders.

RESULTS

Muscular fitness was higher in older adolescents than in younger adolescents. Cardiorespiratory fitness was higher in younger compared to older females, as well as in early puberty compared to late puberty. In males, cardiorespiratory fitness was higher in younger adolescents, but no differences were observed when it was analysed according to sexual maturation status.

CONCLUSION

Normative data for several health-related physical fitness components according to chronological and biological age are provided in this report. Discrepancies between biological and chronological age analysis were higher for cardiorespiratory fitness than for muscular fitness.

Physical fitness effect on bone mass is mediated by the independent association between lean mass and bone mass through adolescence: a cross-sectional study

We studied 278 adolescents (169 females) aged 13.0-18.5 years to elucidate whether an independent effect of physical fitness and lean mass in the differences between male and female bones can be detected. Lean and fat masses and bone mineral content (BMC) were measured with DXA. Physical fitness was evaluated with six different tests included in the EUROFIT test battery (flexibility, isometric, dynamic and endurance strength, speed, and cardiovascular fitness). To test the independent relationship between physical fitness and bone mass, multiple regression analysis was applied, including lean mass, age, and Tanner development as covariates. The males had a 43% lower fat mass and 40% and 16% higher lean mass and total BMC compared with the females (all P < 0.05). After adjustment for differences in body size and lean mass, the females exhibited a 7.4% higher BMC than the males (P < 0.05). The multiple regression analysis showed that lean mass had an independent relationship with bone mass (P < 0.001), explaining 67% of the total variance in whole-body BMC. In males, change in R (2) was 0.658 for hand grip and 0.035-0.151 for the rest of physical fitness-related variables; but 0.019-0.042 in females (all P-0.001); however, the independent relationships between physical fitness and bone disappeared after controlling for lean mass. In conclusion, it is likely the differences between male and female in bone mass could be explained by differences in lean mass and physical fitness.