Best Hit the Gym Soon: Exercise and MCI

There are few domains of physical function upon which exercise does not have a positive impact. Neurologic function is not different in this respect. There are good data on exercise and Alzheimer's Disease. Fewer data are available regarding exercise and minimal cognitive impairment (MCI); however, two papers in a recent Archives of Neurology add to the data.

Baker et al sought to study the effects of exercise on biomarkers in persons who were already diagnosed with MCI, and to evaluate gender as a factor in the response to exercise. They randomized participants to a 6 month high intensity exercise program or a stretching paradigm. Thirty three sedentary persons with MCI, but without a number of chronic disease states, were randomized. In addition to fitness and cognitive measures, several metabolic factors such as insulin sensitivity and body fat percentage were monitored.

From a fitness standpoint, results are largely what might be expected: Fitness improved materially in the exercise group. Gender and beta blocker use did not affect improvement. With regard to biomarkers, insulin sensitivity improved for women, but not men. The cognitive outcomes were fairly complex and also reflected a gender difference. More domains improved for women than men, and executive function was particularly improved. Interestingly, verbal memory tasks did not improve with exercise.

The other study was rather different: It was cross-sectional, and population-based, and consequently the study group was much larger. Geda et al studied a subset of a well-established Mayo Clinic cohort. Their goal was to determine whether exercise reduced the probability of developing MCI. The sample was divided into two age strata, 70-79 and 80-89 years old, with an equal number of men and women. Participants completed a questionnaire about exercise habits, which divided exercise intensity into three groups and ascertained exercise habits in both mid-life and late life. Exercise frequency was also quantified. The analysis included 198 persons with MCI and 1,126 without.

Exercise reduced the probability (odds ratio; OR) of developing MCI. Differences reaching statistical significance were: Late life light exercise: OR 0.69 (0.47-1.00; P=.048); Moderate exercise: Mid-life OR 0.61 (0.43-0.88; P=.008); Late life OR 0.68 (0.49-0.93; P=.02). While vigorous exercise did not reach significance, the authors attributed that to a lack of statistical power in the sample.

So, exercise is of benefit in MCI. The high intensity exercise trial showed particular benefit for women, but men benefited as well. And, moderate exercise in both mid-life and late life reduces the probability of developing MCI. More vigorous exercise may as well, but this has yet to be clearly demonstrated. I also note that both manuscripts reviewed a number of other studies regarding exercise and cognitive function, and in no case did exercise have a deleterious effect. Consider these findings yet another reason to keep that New Year's resolution regarding using that health club membership.