Exercising for 150 minutes each week may be the best treatment for Alzheimer's, according to a study published in the Journal of Alzheimer's Disease.
Researchers from the University of Maryland School of Public Health conducted the study, which reveals that exercise could improve cognitive function in people at risk of Alzheimer's by improving the efficiency of brain activity.
The study analyzed 17 participants with mild cognitive impairment (MCI) - early memory loss associated with Alzheimer's disease - alongside 18 controls. Both groups were of similar age, gender, education, genetic risk and had similar medication use.
The participants were asked to carry out a 12-week exercise program, which consisted of walking on a treadmill at moderate intensity while being supervised by a personal trainer.
Before and after the exercise program, both groups were asked to complete memory tests.
The first was a fMRI famous name discrimination task. This is a memory test requiring the participants to identify famous names as their brain activity was measured.
The second was a list learning task. This test involved the participants recalling words read to them from a list over five consecutive attempts, and again after being distracted with a different list.
'No drug can do what we showed'
Results of the study showed that both groups improved their fitness levels by around 10%.
But the fMRI test taken after the exercise program revealed a significant increase in the intensity of brain activation in 11 brain regions as the participants correctly identified famous names.
The areas of the brain activated with improved efficiency were the same areas of the brain that lead to a diagnosis of Alzheimer's disease. The areas included were the precuneus region - the area involved in episodic memory, the temporal lobe and the parahippocampal gyrus - an area that plays a role in memory encoding and retrieval.
Dr. J. Carson Smith, assistant professor in the Department of Kinesiology at the university, says:
"We found that after 12 weeks of being on a moderate exercise program, study participants improved their neural efficiency - basically they were using fewer neural resources to perform the same memory task.
No study has shown that a drug can do what we showed is possible with exercise."
Results of the study also showed improved memory recall within the list learning task.
Dr. Smith adds:
"People with MCI are on a very sharp decline in their memory function, so being able to improve their recall is a very big step in the right direction."
Memory boosted by 'moderate exercise' levels
The researchers say that what makes these results even more interesting is that these results were achieved using the levels of exercise that are in line with physical activity recommendations for older adults.
The guidelines encourage moderate intensity exercise over most days, totaling 150 minutes each week, the researchers add.
The study authors say that this research suggests that exercise could limit the need for over-activation in the brain in order to recall memory. They add that this is encouraging for those who want to preserve brain function.
Dr. Smith says for further research, he would like to look at a larger study involving more participants who are healthy but have a higher risk of Alzheimer's genetically.