Mind-Body Circuit Training
Circuit training generally refers to a sequence of varying exercises, often on different machines, resulting in a circuit through both body parts and the gym. But a new study suggests a different meaning altogether, at the interface of mental and physical health. There is a circuit in which each of these influences the other. The study, published in JAMA Psychiatry, relied on a 1958 birth cohort from England, Scotland and Wales to examine the associations between physical activity and symptoms of depression over a span of decades. The number of depressive symptoms, the presence or absence of overt depression, and weekly physical activity were analyzed in more than 10,000 people for a period of 50 years.
The investigators reaffirmed what prior research had suggested: Routine physical activity appeared to reduce the likelihood of depressive symptoms and depression. Their relatively novel contribution was to note the reciprocal association: Depressive symptoms seemed to reduce the likelihood of current or future physical activity as well.
Physical activity has long been considered a defense against depression. Studies have suggested both a preventive and therapeutic role. An association has been established between physical activity and mental health in general.
In addition, there has long been evidence that cognitive function benefits from physical activity. Alzheimer's dementia shares many risk factors with cardiovascular disease, and has been considered by some experts a variant of insulin resistance. Physical activity is protective, as are other efforts to mitigate cardiac risk. There is some evidence in support of cognitive calisthenics as well, but the best evidence we have for preserving one's mind involves minding one's body.
Of course, this is all anticipated in the most universal of all anatomy lessons: The shinbone is connected to the ankle bone.
That we have such terms as " mind body medicine" and the "mind body interface" is testimony to an apparent need to resynthesize what we have artificially deconstructed. We have tended to differentiate ailments of body and mind as if the neck were an anatomical barrier, rather than a junction. The disparaging notion that a condition might be "all in your head" is indicative of how extreme the distortions can become.
But, of course, mind and body were never separate. Chronic, physical illness is discouraging, and eventually, potentially depressing. Mental illness saps physical energy, and often manifests in a variety of physical symptoms. The experience of anxiety as "butterflies in the stomach," likely common to us all, is just one variation on this expansive theme.
The findings in the new study derive directly from the ineluctable connections of body and mind. Routine physical activity may prevent or ameliorate depression in a variety of ways, from stabilizing hormone levels, to enhancing blood flow, to improving self-esteem. Depressive symptoms may undermine the resolve to exercise directly, by sabotaging self-esteem, draining energy, compromising sleep quality and other mechanisms.
Exercise apparently defends against depression, and is likely to be among the more effective treatments for it as well. So exercise can be prescribed to help prevent depression. In some cases, it may be the only defense required. In other cases, it may work best in combination with other strategies.
When depression is interfering with exercise, however, "just do it" may not suffice. Other treatments of depression may need to come first. When symptoms are somewhat alleviated, the initiation of exercise should be less daunting. Exercise can then follow as part of the long-term strategy to treat and prevent depressive symptoms.
The new study was observational and could only show associations; it was not designed to prove cause and effect. But the findings were robust, and in the context of prior, related research, seem fairly conclusive. The circuit relating physical activity and mental health can run both ways, for good or bad effect.
Lack of exercise in a vulnerable individual may allow depression to express itself, which may in turn undermine any chance for initiating exercise. This is a negative feedback loop we certainly want to avoid.
The same circuit in reverse is another story. Routine physical activity can help prevent depression and stabilize mood, which in turn contributes to the motivation needed to keep exercising. Cultivating the circuit in this direction, the benefits redound to mental and physical health alike.
David L. Katz, MD, MPH, FACPM, FACP, is the founding director of Yale University's Prevention Research Center; president of the American College of Lifestyle Medicine; editor-in-chief of the journal Childhood Obesity; chief science officer for NuVal LLC; and director of the Integrative Medicine Center at Griffin Hospital. A clinician, researcher, author, inventor, journalist and media personality, Dr. Katz is the recipient of numerous awards and recognitions, including an honorary doctoral degree and widely supported nominations for the position of U.S. Surgeon General. He has authored nearly 200 scientific papers and chapters, 15 books, and hundreds of on-line columns and blogs -- with a resulting following of well over a quarter million people. A two-time diplomat of the American Board of Internal Medicine, and a board-certified specialist in preventive medicine/public health, he is recognized globally for expertise in nutrition, weight management and the prevention of chronic disease. He has been acclaimed by colleagues as the "poet laureate" of health promotion.
