Sleep, Exercise, and Nutrition for Vietnamese Adolescent Academic Performance: Empirical State, Mechanism, Dose-Response, and Exam-Cycle Operational Guidance

Any guidance series for Vietnamese adolescents 14– 19 that omits the physical substrate — sleep, exercise, and nutrition — is structurally incomplete because the cognitive and emotional levers the series teaches ride on a substrate that the modal Vietnamese exam-pressure 17-year-old has actively eroded. This paper compiles the empirical evidence on that substrate. Four questions are addressed. (a) Sleep: bestavailable evidence [1], [2], [3], [4], [5], [6], [7], [8], [9], [10] converges on three high-confidence findings — 8–10 hours is the consensus duration recommendation, the adolescent circadian phase delay is biologically real and not willpower-solvable, and sleep restriction's cognitive effect is well-established but moderate (typical effects in the small-to-medium range for academic and executive function, larger for mood). (b) Exercise: Singh 2019 [11], Lubans 2016 [12], Biddle-Asare 2011 [13], Donnelly 2016 [14], Hillman 2008 [15] converge — exercise-cognition effect sizes for adolescents are real but moderate (typical d ≈ 0.2–0.4) and substantially smaller than popularised claims; exercise-mentalhealth effects are larger and more consistent; chronic MVPA at the WHO 2020 recommendation (≥60 min/day) [16] produces measurable cognitive and mood benefit. (c) Nutrition: Adolphus 2013 [17] and Hoyland 2009 [18] document that breakfast effects on adolescent cognition are mixed and sample-dependent, attenuated when nutritional baseline is adequate ("breakfast is the most important meal" is not supported at the strength asserted); Lane 2024 BMJ [19] documents population-level harm of ultraprocessed food; PREDIMED [20] and Mediterraneanpattern evidence support whole-food dietary patterns; caffeine in adolescents [21], [22] operates bidirectionally with sleep. (d) Operational guidance for the modal exam-pressure 17year-old (≤6 hours sleep, ≤90 min/week exercise, breakfast skipping, caffeine plus sweetened beverages) is given as floor recommendations, realistic intermediate targets, and commonmistake displacements, integrated with i5.2 burnout-prevention. The substantive operational contribution is the Substrate × DoseResponse × Evidence-Strength table (§IV). The Vietnamese double burden of malnutrition (coexisting undernutrition and obesity, documented in the Vietnam National Nutrition Survey 2020 [23]) is treated as population-level realism. Effect-size honesty is non-negotiable; popularised over-extrapolations of exercise-cognition and breakfast-cognition findings are explicitly bounded and not carried into operational guidance.