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Paed Obesity – Improved cognitive health

Evidence Summary
A randomised controlled trial involving 304 post-pubertal adolescents with overweight or obesity aged 14-18 where each person was randomised to 1 of 4 groups (aerobic training, resistance training, combined aerobic and resistance training and a non-exercising control) for 22 weeks showed training did not have significant effect on serum BDNF (brain derived neurotrophic factor) levels, which encourages neurons and increases growth and differentiation of new neurons. All had had dietary counselling regarding calorie deficit of 250kcal daily. Exercise prescription was 4 times a week progressing to 45 minutes/session or 90 minutes combined.

A systematic review by Bustamente et al showed overweight or obese children may derive more cognitive benefit from doing physically active lessons versus sedentary lessons than their normal weight peers would. Findings suggested short bouts of intense activity would elicit more benefit for overweight or obese children.

Neuroimaging revealed beneficial effects on exercise intervention in children who had provided usable brain scans, which may be more responsive than cognitive tests to the effect of exercise intervention. There was a possible mechanistic link between weight loss and cognitive benefits from a physical activity intervention.
Overweight or obese children had greater cognitive benefits than normal weight children from increased physical activity.
It also showed physical activity benefit on executive function might in turn facilitate an increase in physical activity, generating gains in executive function, and so on, on an upward spiral.

Another systematic review by Carson et al looked at 96 studies representing 71291 participants from 36 countries.
Physical activity interventions were consistently associated with improved motor and cognitive development in obese or overweight children.
Moderate to vigorous physical activity was favourably associated with multiple health indicators and more physical activity appeared better for obese children’s overall general health.

Another systematic review by Martin et al looked at 18 studies of 2384 children and adolescents with obesity and overweight. 5 were randomised control trials and 13 were cluster randomised control trials. There was high quality evidence for physical activity only interventions showing improvement in mean cognitive executive function scores – 5 scale points higher for the after-school exercise group compared to standard practice.
A systematic review by Pate et al of 27 studies involving obese children under 6 and physical activity interventions showed strong evidence that higher amounts of physical activity are associated with positive effects in selected indicators of cognitive development and academic outcomes.
Quality of Evidence
Grade B – systematic reviews which suggests PA may improve cognitive function in this group.

Strength of Recommendation
Grade 1 – Strong evidence – There is strong evidence to support an improvement in cognitive development in the early years,
Grade – Moderate – Mixed evidence to support academic performance after early childhood.

There is an association between increased levels of physical activity in obese/overweight children and improved cognitive benefit. Increased physical activity and active lessons may improve drive and subsequently improve cognition further.

  1. Effects of Aerobic Training, or both on brain-derived Neurotrophic Factor in Adolescents with Obesity: The Hearty Randomised Controlled Trial. Goldfield G, Keeny G, Prud’Homme D, Holcik M, Alberga A, Fahnestock M, Cameron J, Doucette S, Hadjiyannakis S, Tulloch H, Tremblay M, Walsh J, Guerin E, Gunnell K, D’Anguilli A, Sigal R.
  2. Physical activity Interventions for Neurocognitive and Academic Performance in Overweight and Obese Youth: A systematic Review. Bustamente E, Williams C, Davis C.
  3. Systematic Review of the Relationships between Physical Activity and Health Indicators in the Early Years (0-4 years). Carson V, Lee EY, Hewitt L, Jennings C, Hunter S, Kuzik N, Stearns J, Powley Unrau S, Poitras V, Gray C, Adamo K, Janssen I, Okely A, Spence J, Timmons B, Sampson M, Tremblay M.
  4. Physical Activity, Diet and Other Behavioural Interventions for Improving Cognition and School Achievement in Children and Adolescents with obesity or overweight. Martin A, Booth JN, Laird Y, Sproule J, Reilly JJ, Saunders DH.
  5. Physical Activity and Health in Children Younger than 6 years: A systematic review. Pate R, Hillman C, Janz K, Katzmarzyk P, Powell K, Torres A, Whitt-Glover M.