What do researchers Aladdin Shadyab, Prabha Siddarth, and James Levine have in common? They all have found evidence for the benefits of walking and moving and the harm to our brains of being too sedentary.
In Shadyab’s study, nearly 1500 women ages 64 to 95 who were part of the Women’s Health Initiative (WHI) were asked to complete questionnaires and wear an accelerometer for seven consecutive days to track their movements. The study also measured leukocyte telomere length (LTL). Shadyab’s study found that cells age faster with a sedentary lifestyle. Telomeres, the parts of chromosomes that control aging, naturally shorten as we age, but poor lifestyle choices, such as not exercising, can speed up that process. The women who got less than 40 minutes/day of moderate to vigorous exercise and also reported more than 10 hours/day of sitting had cells that were eight biological years older than those of their more active peers. An additional finding was that women who sat longer did not have shorter telomere length if they exercised for at least 30 minutes a day, lending support to the importance of exercise for brain health.
In Siddarth’s study, UCLA researchers asked 35 people ages 45 to 75 about their physical activity levels and the average number of hours per day they spent sitting. They also gave each participant a high-resolution MRI scan, which shows the medial temporal lobe (MTL), a brain region involved in the formation of new memories.
The researchers found that sedentary behavior is a significant predictor of thinning of the MTL, which can be a precursor to cognitive decline and dementia in middle-aged and older adults. Physical activity, even at high levels, is insufficient to offset the harmful effects of sitting for extended periods. Researchers observed that reducing sedentary behavior may be a possible target for interventions designed to improve brain health in people at risk for Alzheimer’s disease.
James Levine is also convinced that sitting too much is detrimental to our brains. In addition to contributing to the obesity and diabetes epidemics, Levine says, sitting too much makes us less productive, more depressed, and less mentally sharp. In his 2014 book, Get Up! Why Your Chair Is Killing You and What You Can Do About It, he suggests that people are smarter when they’re moving, mainly because in those first 90 seconds of getting up, the whole brain goes into a state of alertness.
Lastly, the National Centre for Sport and Exercise Medicine in England states that, “Too much sitting may be detrimental to health. All age groups spend the majority of their day sitting but adults over 65 spend the most time of all age groups sitting.”
So, if you want to age well and have your brain be more alert, don’t just sit there, get up and move!!
References:
Levine, J.A. (2014). Get Up!: Why Your Chair is Killing You and What You Can Do About It. NY: St. Martin’s Press.
Shadyab, et al. (2017 Feb). Associations of Accelerometer-Measured and Self-Reported Sedentary Time With Leukocyte Telomere Length in Older Women. American Journal of Epidemiology, 1;185(3):172-184. doi: 10.1093/aje/kww196.
Siddarth, P., et al. (April 12, 2018). Sedentary behavior associated with reduced medial temporal lobe thickness in middle-aged and older adults. PLOS One. https://doi.org/10.1371/journal.pone.0195549