Brain and Brawn: How muscle prevents mental illness revealed
There are two kinds of people in the world: those who divide the world into two kinds of people, and those who don’t.
Robert Benchley
Lumpers and splitters see the world differently. The view through either lens can invigorate or inhibit any field. Western civilization has had a more splitting than lumping temperament and our understanding of humans and health has suffered for it.
The central idea of dualism is that for any particular domain there are two fundamental categories. Prominent examples of such thinking have included the splitting of good and evil, God and Devil, mind and body.
The notion of a mental-physical dualism has dominated medical science and fostered a reductionist model. People were seen as machines to be understood by analyzing the function of their parts. This view defined health as the absence of diseased components rather than the successful integration of complex physical, psychological, and social realities required to experience wellbeing.
The conceptualization of a person as a complex collection of cross-talking biopsychosocial regulatory systems that co-create our physical and subjective realities is only beginning to take hold. In a remarkable series of recent experiments the essential collaboration of muscle and mind, entities more often split than lumped, has been elegantly demonstrated.
Jorge Ruas’ team at the Karolinska Institutet in Sweden showed how working muscle produces an enzyme that breaks down kynurenine, a compound found in higher levels in people with depression and other mental illnesses. The enzyme converts kynurenine into kynurenic acid, which cannot cross the blood-brain barrier. By blocking access, active muscle products protect the brain from the stress-related agents associated with depression.
We think of diseases as independent entities. Each claims its own dominion of experts whose language has grown increasingly unintelligible to other experts. We are as likely to associate muscle and mood as to buy bread from a butcher.
This traditional conceptualization does little to prevent the most common illnesses of our time. How we classify diseases is important because it establishes a conceptual framework for understanding the problem and formulating a solution.
“The whole is more than the sum of its parts” has never been more meaningful. We now appreciate that the symbiotic bacteria that inhabit our bodies are as important as the people that inhabit our social circle. Health is integration, coordination and affiliation. There are no solos.
