The findings are based on an assessment of U.S. citizens, and was largely undertaken through questionnaire and observation. The research compared those who take moderate-to-high levels of exercise with those who took no exercise.
The research team was led by Dr. Clinton Wright, who is from the University of Miami. Wright looked at the records of 876, who had signed-up to the Northern Manhattan Study. This wider study is a research study of stroke and stroke risk factors among the multi-ethnic community of Northern Manhattan, New York.
Importantly, in terms of the applicability of the research, the average age of each participant was 63 years old (from the outset of the study.) The participants were tracked over a seven-year period. At intervals, the study participants provided information about their fitness regime and they undertook various mental tests (both verbal and numerical.) The tests were designed to cover: “processing speed, semantic memory, episodic memory, and executive function.”
In addition, the brains of the subjects were examined via magnetic resonance imaging (MRI), to scan for any anatomical or physiological variations.
The data is skewed to an extent because the majority of the participants undertook little exercise (90 percent of participants.) Of the 10 percent classed as ‘active’, these people regularly ran, went to aerobics classes or partook in calisthenics.
Over time it was found those who did not exercise regularly underwent a decline when carrying out certain cognitive tests, such as working with numbers or recalling words from a list. These patterns were shown by correlation and do not directly imply causation.
While the study ran for 7 years, the researchers assessed lifestyle factors, such as smoking, drinking alcohol, and some ill-health measures (derived from the MRI scans), and extrapolated the data. Here it is claimed that regular exercise, with all other things being equal, avoids 10 years of cognitive aging. Importantly, this did not infer any reduction in physical aging.
The research conclusion was: “a low level of leisure-time physical activity is independently associated with greater decline in cognitive performance over time across domains.”
In assessing these results it should be noted that the effects apply to people in the later stages of middle age and the group assessed was relatively small. Moreover, the test group (those who exercised) was self-selecting and comprised of less than 100 people. Furthermore, there was no indication as to the effect of ‘moderate’ exercise, since none of the subjects fell in (or were placed in) such a group. Care should be taken before reading too much into the results. Nonetheless, the analysis should trigger further research.
The findings are published in the journal Neurology. The research is called “Leisure-time physical activity associates with cognitive decline.”
