Obesity impairs academic attainment in adolescence: findings from ALSPAC, a UK cohort.

OBJECTIVE: While being overweight or obese in adolescence may have detrimental effects on academic attainment, the evidence base is limited by reliance on cross-sectional studies with small sample sizes, failure to take account of confounders and lack of consideration of potential mediators. The present study aimed to address these limitations and examine longitudinal associations between obesity in adolescence and academic attainment. DESIGN: Associations between weight status at 11 years old and academic attainment assessed by national tests at 11, 13 and 16 years were examined in the Avon Longitudinal Study of Parents and Children. Healthy weight was defined as body mass index (BMI) Z-score <1.04; overweight as BMI Z-score 1.04-1.63; obesity as BMI Z-score ⩾1.64. PARTICIPANTS: Data from 5966 participants with objectively measured weight status were examined: 71.4% were healthy weight (1935 males; 2325 females), 13.3% overweight (372 males; 420 females) and 15.3% obese (448 males; 466 females). RESULTS: Girls obese at 11 years had lower academic attainment at 11, 13 and 16 years compared with those of a healthy weight, even after controlling for a wide range of confounders. Associations between obesity and academic attainment were less clear in boys. The potential mediating effects of depressive symptoms, intelligence quotient (IQ) and age of menarche in girls were explored, but when confounders were included, there was no strong evidence for mediation. CONCLUSIONS: For girls, obesity in adolescence has a detrimental impact on academic attainment 5 years later. Mental health, IQ and age of menarche did not mediate this relationship, suggesting that further work is required to understand the underlying mechanisms. Parents, education and public health policy makers should consider the wide reaching detrimental impact of obesity on educational outcomes in this age group.

Associations between objectively measured physical activity and academic attainment in adolescents from a UK cohort.

BACKGROUND: To test for cross-sectional (at age 11) and longitudinal associations between objectively measured free-living physical activity (PA) and academic attainment in adolescents.Method Data from 4755 participants (45% male) with valid measurement of PA (total volume and intensity) by accelerometry at age 11 from the Avon Longitudinal Study of Parents and Children (ALSPAC) was examined. Data linkage was performed with nationally administered school assessments in English, Maths and Science at ages 11, 13 and 16. RESULTS: In unadjusted models, total volume of PA predicted decreased academic attainment. After controlling for total volume of PA, percentage of time spent in moderate-vigorous intensity PA (MVPA) predicted increased performance in English assessments in both sexes, taking into account confounding variables. In Maths at 16 years, percentage of time in MVPA predicted increased performance for males (standardised ß=0.11, 95% CI 0.00 to 0.22) and females (ß=0.08, 95% CI 0.00 to 0.16). For females the percentage of time spent in MVPA at 11 years predicted increased Science scores at 11 and 16 years (ß=0.14 (95% CI 0.03 to 0.25) and 0.14 (0.07 to 0.21), respectively). The correction for regression dilution approximately doubled the standardised ß coefficients. CONCLUSIONS: Findings suggest a long-term positive impact of MVPA on academic attainment in adolescence.

Effects of dehydration and fluid ingestion on cognition.

The effects of exercise-induced dehydration and fluid ingestion on men's cognitive performance were assessed. Eleven young men attended separate sessions in which each individual cycled in a controlled environment at 60 % of V.O (2max) for periods of 15, 60, or 120 min without fluid replacement or 120 min with fluid replacement. Immediately following the assigned submaximal exercise period, the participant completed a graded exercise test to voluntary exhaustion. An executive processing test and a short-term memory test were performed prior to and immediately following exercise. Choice-response times during the executive processing test decreased following exercise, regardless of the level of dehydration. Choice-response errors increased following exercise, but only on trials requiring set shifting. Short-term memory performance improved following exercise, regardless of the level of dehydration. Changes in cognitive performance following exercise are hypothesized to be related to metabolic arousal following strenuous physical activity.

Men's and women's perceptions of effort during progressive-resistance strength training.

Previously sedentary adult men (M age=34.3 yr.) and women (M age =41.8 yr.) participated in a 25-wk., 7-station circuit-training program designed to evaluate the effects of a low-volume (1 set) and a high-volume (3 set) exercise regimen on the development of muscular strength. Participants completed the Borg scale of perceived exertion immediately following a chest-press exercise and a leg-extention exercise. Neither exercise volume nor sex classification was related to participants' ratings of exertion; however, exertion ratings for both exercises increased over the course of training.

Effects of memory demand and motivation on sustained attention in young and older adults.

In two experiments, young and older adults performed 60-min cognitive vigilance tests in which memory demands were equated for individual differences in digit span. In the first experiment, the effects of monetary reward on subjects' performance were assessed. The sustained attention of young and older adults who were both paid for their participation did not differ, and it did not decline during the vigil, but young adults who were not paid for their participation evidenced a significant vigilance decrement. In the second experiment, memory demands were increased and there was no mention of monetary reward for participation. The attention of young adults declined rapidly, but that of older adults did not evidence a vigilance decrement. Subjects' sustained attention is explained in terms of task characteristics and intrinsic and extrinsic motivational factors.

Visuospatial attentional shifts and choice responses of adults and ADHD and non-ADHD children.

18 adults, 17 ADHD children, and 18 non-ADHD children performed a choice-response task on which the spatial location of a target was sometimes compatible and sometimes incompatible with priming cues that varied between 50 and 1000 msec. Children's response latencies differed from adults' response latencies as a function of the delay between priming cue and target onset. A cost-benefit analysis indicated that valid stimulus cues facilitated performance and invalid stimulus cues impeded performance similarly for the three groups. Choice-response errors following invalid cues did not differ between ADHD and non-ADHD children; however, adults made more choice errors than children at 150-msec. and 300-msec. delay intervals. Developmental factors that may underlie differences between children's and adults' response speed and response accuracy are discussed.

Effects of target probability and memory demands on the vigilance of adults with and without mental retardation.

The vigilance of young adults with mild mental retardation and without mental retardation was compared in two experiments in which observers performed two memory demanding, cognitively based, 60-minute tests. In Experiment 1, target probability was 5% or 30% with a 1.5-second event rate. Detection by observers with mental retardation declined more rapidly than did that of observers without mental retardation in both target probability conditions; further, their response criterion became increasingly more conservative. In Experiment 2, target probability was 10% or 30% with an 8-second event rate. Observers with mental retardation detected fewer targets under both target probability conditions. Subjects' response criterion differed as a function of level of intelligence from the onset of the vigil and did not change with time on task. Intelligence-related differences in vigilance were explained in terms of subjects' information-processing abilities.

Method of recruiting subjects and performance on cognitive tests.

College students often serve as participants in psychological research. The effects of three methods of recruiting subjects for laboratory tests of attention and memory were assessed in a series of studies. The performance of students who received monetary incentives and the performance of students who received course-credit incentives were compared with the performance of students recruited from classes where research participation was a requirement. Monetary incentives resulted in slight, but significant, improvements in performance on tests of sustained attention and recognition memory. Course-credit incentives did not affect subjects' test performance. Test performance did not differ as a function of the time of the semester when studies were conducted. Recruitment issues pertinent to departmental subject pools are discussed.

Effects of background event rate on sustained attention of mentally retarded and nonretarded adults.

Mentally retarded and nonretarded adults performed four, 60-minute visual vigilance tests in which single digits were presented at either a fast or slow rate. The target event was a "skipped" digit. During two tests the event rate shifted without warning to the alternate event rate after 30 minutes of the vigil. Retarded observers detected fewer targets and made more false alarms than did nonretarded observers in all test conditions. Shifts in event rate influenced the frequency of false alarms made by retarded observers. The differences in performance of retarded and nonretarded adults favor a memory deficit explanation.

Sustained attention of adults with mental retardation.

The sustained attention of young adults with mild mental retardation and those without retardation was assessed during three 50-minute tests in which visual cues were presented successively on a computer-controlled monitor. Target cues occurred on 5% of the stimulus presentations in a random fashion. Significant decrements in target detection were observed in both groups of observers during all tests; however, the vigilance decrement was unrelated to intelligence level. The target-detection ability of observers with and without mental retardation did not differ on a recognition task. The observers with mental retardation detected significantly fewer target events than did observers who were not retarded on two tasks requiring judgments to be made on the basis of a remembered standard. These data suggest the sustained attention of adults with mental retardation differs from that of adults without mental retardation on vigilance tasks that place demands on memory abilities.

The effects of exercise on the health, intelligence, and adaptive behavior of institutionalized severely and profoundly mentally retarded adults: a systematic replication.

Institutionalized severely and profoundly mentally retarded adults participated in a 7-month program of rigorous aerobic-type exercises. The effects of the treatment on the physical fitness, intelligence, and behavior of subjects were assessed. Fifty men and women were matched in pairs based on IQ, CA, and sex and assigned randomly to an experimental (E) or control (C) group. Those in the E group met 3 hours per day, 5 days per week and received a treatment that consisted of an exercise program that included jogging, running, dance-aerobics, and circuit training. The C group continued their normal institutional training programs. The treatment produced significant improvement in the cardiovascular efficiency of subjects; however, no changes in intelligence or adaptive behavior were obtained. Although standardized tests reflected little improvement in psychological or behavioral variables due to treatment, subjective reports suggest that exercise training may serve as a more practical habilitation program for severely and profoundly mentally retarded individuals than those typically employed in institutional settings.

Effects of exercise on the physical fitness, intelligence, and adaptive behavior of institutionalized mentally retarded adults.

The effects of a seven-month aerobic-type exercise program on physical fitness and intelligence of institutionalized adult mentally retarded persons were evaluated. Sixty-five subjects, matched on IQ, CA, and sex, were assigned randomly to exercise (PF), attention control (AC), and nonintervention control (C) groups. PF and AC groups participated in 139 training sessions, three hours per day, five days per week. The exercise consisted of running/jogging, calisthenics, and circuit training; those in the AC groups received a special education program; the C group continued their normal institutional training programs. Cardiovascular efficiency improved in the PF group. IQ and adaptive behavior did not improve as a result of any treatment. Even though standardized tests reflected little change in adaptive behavior of participants, subjective reports suggest PF training may serve as an effective habilitation program for many institutionalized mentally retarded adults.

Vitamin/mineral supplements and intelligence of institutionalized mentally retarded adults.

Vitamin/mineral supplements were administered to institutionalized mentally retarded adults in a double-blind study over a 7-month period. No changes were observed in IQ nor in adaptive behavior, i.e., independent living skills within the institution. This was a replication with adults of a previous study of children that had obtained positive results. Possible reasons for the different findings were discussed.

Training an autistic client: the effect of brief restraint on disruptive behavior.

A profoundly retarded autistic client who was making no progress in self-help skill training sessions exhibited disruptive behaviors which were incompatible with training goals. These behaviors included withdrawal, self-stimulation and mascular rigidity. Following baseline measurement of the effectiveness of standard behavior-shaping techniques, brief restraint was implemented to decelerate the disruptive behaviors. During treatment conditions a two-trainer procedure was employed. All task-oriented behavior was followed by positive reinforcement. The disruptive behaviors of the client decreased following the introduction of the restraint procedure. As the disruptive behaviors were reduced, progress in a self-help training program was evidenced. Following a fading procedure a single trainer could control the behavior of the client via positive reinforcement alone.