Physical exercise may help to slow the decline of thinking and memory skills as people age, according to a recent study out of the University of Edinburgh.

During the study almost 700 participants took part in cognitive testing and magnetic resonance imaging (MRI) of the brain at age 70, and again at age 73.

Questionnaires were used to assess the volunteers' physical activity levels as well as their more cerebral hobbies. Adjustments were made to account for variables like overall health conditions, social class, and age.

Study participants who were at least 70 years old and engaged in regular exercise produced MRI scans showing less deterioration in thinking and memory skills than those who were not physically active.

Estimating the brain size of participants when they were younger, and comparing the earlier MRIs with the current scans, the researchers also analyzed structural features of the brain that generally change with cognitive decline. It was determined that there was less atrophy in the brains of the more frequent exercisers.

The researchers found no direct relationship between participants' mental activity or other leisure activities and the presence of brain atrophy that would indicate cognitive decline.

While the study shows that exercise plays a larger role in slowing the decline in cognitive functioning and atrophy of the brain than intellectual hobbies, further research is needed to understand exactly why that is. Researchers stress the importance of following the study subjects in the coming years to see if there are significant changes in structural features of the brain.

The study authors conclude that exercise may have a protective effect on cognitive function as we age. It is already understood that exercise provides important health benefits throughout our lives, but staving off cognitive decline in our senior years may give us more reason to exercise during middle age.

Research into the causes and risk factors for dementia are also key to finding ways to slow or prevent its onset.

Even a short burst of exercise can improve memory in seniors who exhibit minor cognitive impairment.

While prior studies have analyzed the effect of regular exercise on cognitive function and health as we age, a new study examines how a short session of intense exercise impacts memory skills.

Researchers from UC Irvine's Center for the Neurobiology of Learning & Memory studied people from 50 to 85 years old, some who had minor memory problems and some who did not. Volunteers viewed photographs of nice things, including animals and outdoor nature scenes. Then some were asked to ride a stationary bike at 70 percent of their maximum capacity for six minutes.

Participants were given a memory test one hour after exercise. Asked to recall details of the photos they saw before exercising, there was a marked rise in memory skills in those who had exercised when compared with those who had not. This was true for cognitively impaired volunteers as well as for those who were healthy.

"We found that a single, short instance of moderately intense exercise particularly improved memory in individuals with memory deficits. Because of its implications and the need to better understand the mechanism by which exercise may enhance memory, we're following up this study with an investigation of potential underlying biological factors," said lead researcher Sabrina Segal.

Segal theorizes that the increase in memory skills may be due to a chemical called norepinephrine, which is released during exercise. Previous studies showed that inhibiting norepinephrine actually hinders memory, while raising norepinephrine levels pharmacologically can elevate memory skills.

The team's prior research also indicates that after exercise, levels of a biomarker called salivary alpha amylase are higher. Salivary alpha amylase is similar to norepinephrine and proved to have a dramatic effect on study volunteers who had memory problems.

For older people who find maintaining a long-term exercise plan difficult, this finding shows that even short bursts of exercise have a positive effect on cognitive function. That's encouraging news, providing seniors with some additional motivation to engage in physical activity.

Reference
1. UC Irvine Center for the Neurobiology of Learning and Memory. Sabrina Segal, Carl Cotman, and Lawrence Cahill
The study, performed by Edinburgh's Centre for Cognitive Ageing and Cognitive Epidemiology, was published in the October issue of Neurology.