Spark

Spark makes the case that physical exercise is not only good for the body but is one of the most effective interventions available for the brain. John Ratey's central argument is that aerobic activity changes the chemistry and structure of the brain in ways that support mood, attention, learning and resilience to stress, and that treating exercise as optional in mental health care is a mistake.

The proposed mechanism runs through neurotrophic factors, particularly brain-derived neurotrophic factor, which supports the growth and survival of neurons and the formation of new connections. Ratey links exercise to increased BDNF, to the regulation of serotonin, dopamine and norepinephrine, and to neurogenesis in the hippocampus. He applies this to depression, anxiety, attention problems, addiction, hormonal transitions and cognitive ageing, and opens with a school district that put fitness-based physical education at the start of the day.

It is for anyone weighing exercise as part of a mental health or cognitive plan, and for coaches, teachers and clinicians who want a mechanistic account rather than general encouragement.

On the evidence, this is one of the better-grounded popular neuroscience books. The association between regular aerobic exercise and improvements in depressive symptoms, anxiety and executive function is supported by a substantial trial literature, and exercise is recommended as part of treatment in several clinical guidelines. Two cautions are worth holding. The BDNF story is drawn heavily from animal work, and the step from rodent hippocampus to human mood is longer than the narrative implies. The school programme that opens the book is an observational account, not a controlled trial, and the test-score gains cannot be attributed to the exercise alone. The core recommendation is sound; some of the mechanistic confidence is ahead of the human data.