Study effectively.
Live well.

Retrieval: Experiment 1, university students aged 18–24. One-week recall was 56% versus 42% after rereading; the relative difference is approximately 33%. This is passage recall, not a grade improvement.

Spacing: two laboratory studies of vocabulary, facts and object names, with test delays up to six months. The authors report that optimal gaps improved final recall by up to 150%; this is the largest reported benefit, not an average or a guaranteed outcome.

Interleaving: 140 Grade 7 students practised over nine weeks. On an unannounced test two weeks later, mean scores were 72% for interleaved material and 38% for blocked material.

Single-tasking: Experiment 1, 40 university students in a simulated lecture. Mean comprehension scores were 66% without laptop multitasking and 55% with unrelated online tasks.

Sleep and attention: Singapore adolescent experiment, seven nights of 5 versus 9 hours in bed. Outcomes included attention lapses, working memory and processing speed.

Sleep and learning: 56 adolescents aged 15–19. Sleep restriction impaired recall of massed (crammed) vocabulary; spaced vocabulary was more resistant to the effect.

Sleep and food-related control: 64 adolescents, five nights of 5 versus 9 hours in bed. Restricted sleep worsened food-related inhibitory-control task performance and increased reported food reward.

The AASM recommends 8–10 hours of sleep per 24 hours for ages 13–18.

Exercise: PET experiment in 16 adults detected dopamine release during cycling; release correlated with improved reaction time on a Go/No-Go task. The study suggests a mechanism rather than proving improved studying in JC students.

Randomised crossover trial in 30 women aged 18–30 with overweight or obesity. The high-protein, low-carbohydrate dairy breakfast improved concentration-test scores by 3.5 percentage points versus no breakfast, 150 minutes after eating. Dopamine was not measured, and the comparison does not isolate protein from the rest of the meal.

Sugar and alertness: meta-analysis of 31 studies with 1,259 participants; acute carbohydrate intake was associated with greater fatigue and lower alertness within the first hour versus placebo. This does not establish that all carbohydrate-rich meals cause brain fog.

Meal composition: crossover trial in 13 women aged 21–22. A high-fat, high-sugar breakfast increased sleepiness and worsened planning-related performance versus a balanced breakfast of equal energy.

Randomised trial in adults, mean age 32, blocking all smartphone internet for two weeks. Pooled sustained-attention improvement was 0.23 standard deviations. The authors compared its magnitude to ten years of age-related difference on the same task; this is not biological age reversal. It was broader than restricting doomscrolling alone. Only 119 of 467 recruited participants met the preregistered compliance criterion.

Protein mechanism: amino acids are building blocks of neurotransmitters; tyrosine is a precursor of dopamine and noradrenaline. Supplement findings cannot establish that higher-protein meals increase or stabilise dopamine or improve focus through that mechanism.