\nThe benefits of physical activity are well known, from improved mood and sleep to better brain health and increased longevity, so it would seem that more movement is always good.\n<\/p>\n
\nBut a new study challenges this thought, at least when it comes to dementia risk, and renews focus on what is known as the “physical activity paradox.”\n<\/p>\n
MORE: New study challenges notion that marijuana is not addictive<\/a><\/p>\n \nThe physical activity paradox is the hypothesis that exercise done during down time benefits overall health, while exercise done as part of a job may not yield the same positive effects and may actually be detrimental.\n<\/p>\n \nPrior research lends support to the physical activity paradox as it relates to cardiovascular risk and death from all causes.<\/p>\n A 2021 paper<\/a>, for instance, found that higher activity during leisure time was associated with reduced risk of heart attacks, stroke and all-cause mortality, but that physical activity on the job was linked to an increase in these risks. A 2018 meta-analysis<\/a> of 26 different studies also found that, for men, a higher level of physical activity was associated with an increased risk of death from any cause, regardless of level of leisure-time activity.\n<\/p>\n \nThe new study, published Tuesday in The Lancet Public Health, looked more specifically at the impact of work-related physical activity and dementia risk. The findings suggested that leisure-time activities, such as swimming, running, walking and playing sports, was associated with a decreased risk of dementia but that physical activity on the job increased dementia risk.\n<\/p>\n \n“The findings challenge the long-held assumption that ‘every move counts’ for brain health,” said Natan Feter, the study’s first author and a postdoctoral fellow at the University of Southern California.\n<\/p>\n \nThe study analyzed 74 studies involving 4.2 million people, ages 45 to 93, in 30 countries. The researchers tracked participants’ diagnoses for dementia and Alzheimer’s disease.\n<\/p>\n \nPeople who engaged in higher levels of physical activity off the job had a 24% lower risk of dementia than people who were least active. But people who engaged in occupational physical activity had a 20% higher risk of dementia.\n<\/p>\n