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By Philippa Roxby
Health reporter, BBC News
12 October 2019
How fast people walk in their 40s is a sign of how much their brains, as well as their bodies, are ageing, scientists have suggested.
Using a simple test of gait speed, researchers were able to measure the ageing process.
Not only were slower walkers’ bodies ageing more quickly – their faces looked older and they had smaller brains.
The international team said the findings were an “amazing surprise”.
Doctors often measure gait speed to gauge overall health, particularly in the over-65s, because it is a good indicator of muscle strength, lung function, balance, spine strength and eyesight.
Slower walking speeds in old age have also been linked to a higher risk of dementia and decline.
In this study, of 1,000 people in New Zealand – born in the 1970s and followed to the age of 45 – the walking speed test was used much earlier, on adults in mid-life.
The study participants also had physical tests, brain function tests and brain scans, and during their childhood they had had cognitive tests every couple of years.
“This study found that a slow walk is a problem sign decades before old age,” said Prof Terrie E Moffitt, lead author from King’s College London and Duke University in the US.
Even at the age of 45, there was a wide variation in walking speeds with the fastest moving at over 2m/s at top speed (without running).
In general, the slower walkers tended to show signs of “accelerated ageing” with their lungs, teeth and immune systems in worse shape than those who walked faster.
The more unexpected finding was that brain scans showed the slower walkers were more likely to have older-looking brains too.
And the researchers found they were able to predict the walking speed of 45-year-olds using the results of intelligence, language and motor skills tests from when they were three.
The children who grew up to be the slowest walkers (with a mean gait of 1.2m/s) had, on average, an IQ 12 points lower than those who were the fastest walkers (1.75m/s) 40 years later.
The international team of researchers, writing in JAMA Network Open, said the differences in health and IQ could be due to lifestyle choices or a reflection of some people having better health at the start of life.
But they suggest there are already signs in early life of who is going to fare better in health terms in later life.
The researchers said measuring walking speed at a younger age could be a way of testing treatments to slow human ageing.
A number of treatments, from low-calorie diets to taking the drug metformin, are currently being investigated.
It would also be an early indicator of brain and body health so people can make changes to their lifestyle while still young and healthy, the researchers said.
Changes in the immune system explain why belly fat is bad for thinking
DECEMBER 17, 2019
by Whitney Baxter, Iowa State University
https://medicalxpress.com/news/2019-12-immune-belly-fat-bad.html
Iowa State researchers have found for the first time that less muscle and more body fat may affect how flexible our thinking gets as we become older, and changes in parts of the immune system could be responsible.
These findings could lead to new treatments that help maintain mental flexibility in aging adults with obesity, sedentary lifestyles, or muscle loss that naturally happens with aging.
The study, led by Auriel Willette, assistant professor of food science and human nutrition, and Brandon Klinedinst, a Ph.D. student in neuroscience, looked at data from more than 4,000 middle-aged to older UK Biobank participants, both men and women. The researchers examined direct measurements of lean muscle mass, abdominal fat, and subcutaneous fat, and how they were related to changes in fluid intelligence over six years.
Willette and Klinedinst discovered people mostly in their 40s and 50s who had higher amounts of fat in their mid-section had worse fluid intelligence as they got older. Greater muscle mass, by contrast, appeared to be a protective factor. These relationships stayed the same even after taking into account chronological age, level of education, and socioeconomic status.
“Chronological age doesn’t seem to be a factor in fluid intelligence decreasing over time,” Willette said. “It appears to be biological age, which here is the amount of fat and muscle.”
Generally, people begin to gain fat and lose lean muscle once they hit middle age, a trend that continues as they get older. To overcome this, implementing exercise routines to maintain lean muscle becomes more important. Klinedinst said exercising, especially resistance training, is essential for middle-aged women, who naturally tend to have less muscle mass than men.
The study also looked at whether or not changes in immune system activity could explain links between fat or muscle and fluid intelligence. Previous studies have shown that people with a higher body mass index (BMI) have more immune system activity in their blood, which activates the immune system in the brain and causes problems with cognition. BMI only takes into account total body mass, so it has not been clear whether fat, muscle, or both jump-start the immune system.
In this study, in women, the entire link between more abdominal fat and worse fluid intelligence was explained by changes in two types of white blood cells: lymphocytes and eosinophils. In men, a completely different type of white blood cell, basophils, explained roughly half of the fat and fluid intelligence link. While muscle mass was protective, the immune system did not seem to play a role.
While the study found correlations between body fat and decreased fluid intelligence, it is unknown at this time if it could increase the risk of Alzheimer’s disease.
“Further studies would be needed to see if people with less muscle mass and more fat mass are more likely to develop Alzheimer’s disease, and what the role of the immune system is,” Klinedinst said.
Starting a New Year’s resolution now to work out more and eat healthier may be a good idea, not only for your overall health, but to maintain healthy brain function.
“If you eat alright and do at least brisk walking some of the time, it might help you with mentally staying quick on your feet,” Willette said.
More information: Brandon S. Klinedinst et al, Aging-related changes in fluid intelligence, muscle and adipose mass, and sex-specific immunologic mediation: A longitudinal UK Biobank study, Brain, Behavior, and Immunity (2019). DOI: 10.1016/j.bbi.2019.09.008
Journal information: Brain, Behavior, and Immunity
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