I’ve recently come into contact with some exciting research linked to depression and dementia. Several academic papers suggest changes to blood circulation may positively affect mental health. A scientific study of middle-age men who practised sauna bathing in Finland indicated they were less likely to experience dementia than their peers who didn’t take saunas. A degree of support in this general direction comes from other evidence that cold showers may have a beneficial effect on depression. Over the last decade, we have also started to see claims linking open water swimming (cold water swimming) with improved mental health.
Saunas, cold showers and cold water swimming affect us in different ways, but they all share the ability to alter the body’s temperature. A rapid increase in body temperature leads to a widening (dilation) of the blood vessels, increasing the blood flow. The reverse is true when we get cold, the blood vessels become narrower, constricting the flow. We are uncertain of exactly how rapid temperature changes alter blood flow in the brain, but we can be sure it does have an impact.
So what have showers, sauna and swimming got to do with meditation? What may surprise many people is meditation can also change our heart rate and blood pressure. Since the beginnings of the scientific investigation of meditation, both physiological and psychological effects have been visible. If we go back to the 1930s, the first studies of meditators using electroencephalographic (EEG) technology observed changes to alpha waves in the brain. However, by the 1950s, scientists looked at a much more comprehensive range of changes in meditators, such as the lowering of heart rate, blood pressure and increases in skin conductivity. So from its earliest origins, contemplative science has recognised that practising meditation can lead to physical changes correlated with our mental states.
There is no question that meditation acts differently compared to physical activities in warm or cold environments. But we may find, coincidentally, that cold water swimming, saunas and meditation can all lead to fluctuations in blood flow to the brain.
The term meditation is imprecise; there are, of course, thousands of different meditation and mindfulness methods. Each distinct method is likely to have a particular effect on your mind and body. Rather like physical exercise, mind training will make most of us ‘fitter’ but not in the same way and at the same rate. So when we think about physical and mental changes from meditation, we should always be mindful of not overgeneralising. But even with the limited evidence available there is a case to argue that circulatory changes during meditation may be linked to improved mental health. And that other activities like open water swimming may possess a similar potential to mediate mental states and traits through changes to blood flow.