For all the reasons one normally hears, I am a long-time fan of regular workouts in the swimming pool. Not the least of these is the old joke about how it’s the second-best exercise known to man – and woman – that can be indulged in the prone position. And the killer reason for many of us whose childhood was lived largely on an ice hockey rink is the low impact experience of slicing through water as against pounding your crumbling knees into oblivion on a frozen lake.
The brain gets its fair share of the benefits of swimming, right up there with the aerobic benefits for the heart and lungs, the suppleness for the musculo-skeletal system, and as an aid to better digestion. Just about everyone who has developed a swimming habit will be familiar with the “yoga for the brain” idea: the calming, meditative benefits of the sounds of the rushing water, and the endorphin effect as the “feel-good” chemicals are released into your system as the aerobic effects kick in.
But how about the process of “hippocampal neurogenesis”? With a little rooting around this turns out to be one of those things you probably know something about, but just didn’t know that it was called that. Yet there remain millions of reasonably well-educated people – and being one of them, I know – who were brought up on the notion that we get doled out our birth-ration of a few billion neurons and then proceed over our three score years and ten to bash them about, pickle them and just generally manage to lose so many of them without any of them ever being replaced that we end up with no hope of finding our car keys.
More recent work in brain plasticity and neurogenesis generally – the process by which new neurons are created in at least part of the brain after birth – has shown that new neurons are created throughout life in the hippocampus: that part of the brain largely responsible for learning and memory. And while the neuroscientific community would declare it still to be early days in understanding precisely the relationship between exercise and the rate at which neurons are created or lost, two points are emerging clearly:
First, exercise studies with rodents have shown greater rates of cell production in the hippocampus, as well as enhanced cognitive performance in those rats that had been exercising; and
Second: almost as important as creating new cells is anything that can stop existing cells from dying so quickly. We know that prolonged stress can increase rates of neurodegeneration, and that swimming is one of our best de-stressors.
For decades now I have been thinking while swimming while not thinking too much about how swimming specifically assists thinking. Hippocampal neurogenesis makes perfect sense.