This narrative review on yoga therapy research that was published during the years 2020 to 2023 includes 58 papers. The publications of this period are primarily systematic reviews and meta-analyses of randomized controlled trials. Many of these (15%) are focused on yoga reducing anxiety and depression during pregnancy. Pediatric research has included yoga for motor and cognitive performance in youth and adult research has been focused on yoga for depression, migraines, diabetes and cancer. Surprisingly, studies on older adults including yoga for cognitive dysfunction and for Parkinson's comprise a significant number of the yoga publications (18%). Other studies include comparisons of Tele-yoga and in-person yoga and different yoga styles. Underlying mechanism research suggests that increased parasympathetic activity occurs following yoga as well as a reduction in cortisol and pro-inflammatory cytokines. Methodological problems continue to relate to the combined assessment of multiple yoga styles and their differing intensity and the more frequent measurement of psychological versus physical effects, although the mechanism studies highlight the positive physical effects of yoga.This narrative review involved entering the terms yoga and the years 2020-2023 into PubMed and PsycINFO. The search yielded 349 papers for the last four years. However, following exclusion criteria, including case studies, non-English papers and study protocols, this review is a summary of the research reported in 58 papers. The recent literature on yoga is predominantly focused on the reduction of anxiety and depression during pregnancy and on improving cognitive function in older adults including those with Parkinson's. Other research involves yoga for youth for motor skills and cognitive performance and for adults to reduce depression, migraines and cancer symptoms as well as historical trends in the research and comparisons of different yoga styles including traditional yoga, exercise yoga and restorative yoga. This narrative review is accordingly divided into sections on research trends, comparisons of yoga styles, different age groups and conditions, potential underlying biological mechanisms and methodological limitations.
Research TrendsIn a paper entitled "A PubMed-based exploration of the course of yoga research 1948 to 2020" different types of yoga research are given for each of several time periods [1]. One per cent of the yoga research from 1948 to 2020 occurred during the period 1948 to 1970 and was focused on the exceptional abilities of yoga practitioners. Seven percent of the research was published during the years 1971 to 2000 and was focused on health and therapy. Ninety-two percent of the research was published during the subsequent years 2001 to 2020 and was focused also on health and therapy but with fewer randomized controlled trials compared to systematic reviews and meta-analyses. More specifically from 1981 to 1990 the health and therapy articles were primarily on asthma, stress and diabetes. In the period 1991 to...