Welcome back! I hope you enjoyed the introduction to this series in Stress Part One. If you haven’t yet seen Robert Sapolsky’s talk on stress, please do. I’m not kidding when I say he’s one of the best speakers I’ve ever seen – if the length seems ludicrous, just click somewhere in the middle and watch for two minutes, and I’m sure you’ll get something out of it.
I concluded my introduction last time by saying that I’d next delve into the science. As it turns out, I found a whopping 387 studies that passed my inclusion/exclusion filtering, and – as it also turns out – I’m not a very fast reader. Since I need more time to go through them critically, I wanted to tell you a little bit today about what I found and how I found it.
Studies are being published from all over the world
As you can see in the map above (the featured image), the world is paying quite some attention to the impact of meditation and yoga on stress! Each of the icons represents a university or institute that’s published one or more studies regarding the impact of meditation or yoga on stress. Below are close-ups from a few different regions.
Growing attention to the subject over time
I parsed out the 387 studies I’d found by year in order to see the trend over time. I don’t think it’s surprising that the interest in the impact of meditation and yoga on stress has grown exponentially! To give you a different view of the numbers, 286 of the 387 studies were published in the past ten years – i.e. after 2007.
I wanted to approach this systematically in order to develop a comprehensive view of the available science on the topic, rather than a limited or biased one. I used PubMed to search for the studies; it’s a huge database managed by the US National Library of Medicine and the National Institutes of Health that contains literature from all over the world. On a side note, a lot of articles are free for public access, so if you’re curious check it out!
I searched “meditation OR yoga AND stress” and found 1953 search results. My inclusion criteria were 1) meditation or yoga as an intervention; 2) some component of stress as at least one of the measured outcomes; and 3) availability of the report in English. My exclusion criteria were either a distinct focus in populations with medical/psychiatric illnesses or a focus in niche populations (which had included caregivers of cancer patients, victims of sexual trauma, women who experienced stillbirth, refugees, and inmates.) 391 citations ultimately passed this filtering process, of which 4 were duplicates. I’ve been unable to find or access 45 out of the 387 studies (33 of those 45 were studies published before 2008.) This is all summarized in the diagram below.
Next time I’ll discuss the literature regarding the impact of meditation and yoga on stress for the general population (the 196 studies in the diagram). After that, I’ll discuss the literature on more specific populations such as employees, healthcare personnel, and students (the 146 studies). Thanks for tuning in!
Your friendly neighborhood doctor-in-training/meditation-trainer,