More ways exercise can help seniors fight memory loss

September, 2011

A recent study finds that cognitive decline is greater in older adults who have a high salt intake —but only if they’re not physically active. Another finds that older rats who exercise are protected from memory loss caused by bacterial infection.

A three-year study following 1,262 healthy older Canadians (aged 67-84) has found that, among those who exercised little, those who had high-salt diets showed significantly greater cognitive decline. On the bright side, sedentary older adults who had low-salt consumption did not show cognitive decline over the three years. And those who had higher levels of physical activity did not show any association between salt and cognition.

Low sodium intake is associated with reduced blood pressure and risk of heart disease, adding even more weight to the mantra: what’s good for the heart is good for the brain.

The analysis controlled for age, sex, education, waist circumference, diabetes, and dietary intakes. Salt intake was based on a food frequency questionnaire. Low sodium intake was defined as not exceeding 2,263 mg/day; mid sodium intake 3,090 mg/day; and high sodium intake 3,091 and greater mg/day. A third of the participants fell into each group. Physical activity was also measured by a self-reported questionnaire (Physical Activity Scale for the Elderly). Cognitive function was measured by the Modified MMSE.

And adding to the evidence that exercise is good for you (not that we really need any more!), a rat study has found that aging rats that ran just over half a kilometer each week were protected against long-term memory loss that can happen suddenly following bacterial infection.

Previous research found that older rats experienced memory loss following E. coli infection, but young adult rats did not. In the older animals, microglia (the brain’s immune cells) were more sensitive to infection, releasing greater quantities of inflammatory molecules called cytokines in the hippocampus. This exaggerated response brought about impairments in synaptic plasticity (the neural changes that underlie learning) and reductions in BDNF.

In this study, the rats were given unlimited access to running wheels. Although the old rats only ran an average of 0.43 miles per week (50 times less distance than the young rats), they performed better on a memory test than rats who only had access to a locked exercise wheel. Moreover, the runners performed as well on the memory test as rats that were not exposed to E. coli.

The researchers are now planning to examine the role that stress hormones may play in sensitizing microglia, and whether physical exercise slows these hormones in older rats.

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A study in which 64 sedentary older adults (aged 60-88) participated in a 12-week exercise program found that those who engaged in high-intensity interval training (HIIT) saw an improvement of up to 30% in memory performance while participants who engaged in moderate-intensity aerobic exercise s

A study involving 30 previously physically inactive older adults (aged 61-88) found that a three-month exercise program reversed some brain atrophy.

A long-running study following 387 Australian women found that regular exercise in middle age was the best lifestyle change they could make to prevent cognitive decline in their later years.

A large study, involving nearly 14,000 older adults (50+) participating in the 2006 Health and Retirement Study, found that weaker handgrip strength was associated with a greater risk of developing cognitive impairment, especially severe impairment, over the eight-year study period.

Data from the long-running Rush Memory and Aging Project, involving 960 participants who completed a food frequency questionnaire from 2004 to 2013, found that those who ate one daily serving of green, leafy vegetables had a slower rate of cognitive decline than people who rarely or never ate th

A study involving 99 healthy older adults found that levels of monounsaturated fatty acids were associated with cognitive performance and the organization of the brain's attention network.

Data from 915 older adults (mean age 81.4) participating in the very long-running Rush Memory and Aging Project, has found that those who reported eating seafood less than once a week showed greater cognitive decline compared to those who ate at least one seafood meal per week.

Data from the Canadian Longitudinal Study on Aging, involving 8,574 middle-aged and older adults (aged 45-85), has found that those who ate more vegetables and fruits and more nuts and pulses (such as lentils and beans) scored higher on tests of verbal fluency.

Analysis of data from the Age-Related Eye Disease Study (AREDS) and AREDS2, involving a total of around 8,000 older adults, has found that those with the greatest adherence to the Mediterranean diet had the lowest risk of cognitive impairment.

A 10-year study involving 19,887 middle-aged and older Americans, who completed surveys every two years about their health and lifestyle, has found that those who had a drink or two a day tended to show less cognitive decline, compared to non-drinkers.

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