Sitting for too long may be bad for your brain
Do you consider yourself a couch potato? According to a new study done at UCLA, sitting for prolonged periods of time may be harmful for your brain. Thirty five participants from ages 45 to 75 were recruited and asked about their physical activity patterns such as how many hours they spent sitting down during the previous week. The participants reported average sitting times of three to fifteen hours per day. Researchers then scanned their brains in an MRI and compared the sizes of their medial temporal lobe (MTL), a brain region important for learning and forming episodic memory.
They found that participants who spent more time sitting per day had thinner MTL structures and that sedentary behavior is a significant predictor of MTL thinning. They also found that every additional hour of sitting was associated with a 2% decrease in MTL thickness after adjusting for the subjects’ ages. However, the researchers did not find any correlation between physical activity levels patterns and thickness of the structures, thus showing that physical activity is insufficient to offset the negative effects of sitting for extended periods. The finding that sedentary behavior is associated with reduced MTL thickness is consistent with studies showing extended sitting times increase the risk of heart disease, diabetes, and premature death. While the researchers focused on the hours spent sitting, they did not ask if the participants took any breaks during this period. They also could not say why sitting for extended periods is associated with MTL thinning. One theory is that if sitting for too long compromises the supplies of oxygen and nutrients the brain needs to stay healthy, then it would be reasonable to expect the brain to be unable to maintain its proper volume and start thinning.
For future studies, the researchers plan to follow a group of people for a longer amount of time in order to determine whether sitting causes the MTL thinning or other factors such as race, gender, and weight also play a role in brain health. MTL thinning is considered a precursor to dementia in middle-aged and older adults. The researchers believe that reducing sedentary behavior may prove fruitful in improving brain health in people at risk of Alzheimer’s disease, a condition which reduces the volume of memory-making structures in the MTL including the hippocampus and the entorhinal cortex.
Writer: Nathaniel Meshberg
Editor: Audrey Kim
Sources:
http://www.latimes.com/science/sciencenow/la-sci-sn-sitting-brain-memory-20180413-story.html
https://www.sciencedaily.com/releases/2018/04/180412141014.htm
