Stiffen Your Spine(s) with BDNF

Dolors & Sense 

by Sanford Rose

KISSIMMEE Florida—(Weekly Hubris)—1/30/12—Every so often a newspaper or magazine will publish a grandiose analysis of the so-called economics of exercise.

Such articles purport to view exercising in a capital-budgeting framework: projecting the likely increase in longevity from an exercise program vs. the temporal and monetary costs of engaging in such a program, with all the benefits and costs appropriately discounted to their present values.

That, of course, is nonsense.

While there are some monetary costs involved in pursuing an exercise program, there are no temporal ones.

Exercise time is not a cost; it is a benefit. It is no more a cost than is reading a good book (or Weekly Hubris).

Properly pursued, exercise lengthens one’s lifetime, to be sure. But it also elevates the mood. Even more important, it increases our capacity to enjoy other activities . . .

. . . such as thinking, which a few people still find elevating and enjoyable.

There has been a great deal of recent research on the effect of exercise on neurogenesis—the formation of new neurons and the connections between them.

Follow this causal chain:

Clear thinking depends on the passage of neurotransmitters from one neuron (the pre-synaptic cell) to the next (the post-synaptic cell) across the synaptic cleft.

To better receive these transmissions, the post-synaptic cell has to sport as many antennae as possible.

The antennae are called dendritic spines.

An enzyme called Lim domain kinase 1 facilitates the building of dendritic spines.

That enzyme is activated by BDNF, which is a neurotrophin—nerve-cell growth factor—manufactured in a cellular organelle labeled the endoplasmic reticulum.

BDNF expression, or secretion, occurs during exercise.

The more intense the exercise, the more BDNF is produced, the sturdier and more numerous are the dendritic spines, and the clearer is (or at least can be) our thinking.

Clearer thinking may turn out to be the biggest boon conferred by habitual intense exercise, though it is one that is rarely factored into stylized and often presumptuous economic analyses of alleged benefits and costs.