Background: Cognitive impairment of the elderly contributes to morbidity, loss of quality of life, and impairment of work ability in aging western societies. Thus strategies to maintain cognitive function at an advanced age imply a great challenge to Occupational Medicine.
Aim: To study whether intensive endurance exercise training is associated with better cognitive performance and increases brain-derived neurotrophic factor (BDNF) and insulin-like growth factor (IGF).
Methods: Active elderly marathon runners or bicyclists older than 60 years were recruited and matched with an inactive control group according to age, sex, and education years. After exclusion of various diseases according to the study protocol 56 athletes and 58 controls could be selected for follow-up studies. The influence of endurance training on cognitive function was assessed by the use of the Vienna Neuropsychological Test Battery and the CERAD test battery. Other relevant outcomes were the levels of BDNF, IGF-1, Apo e4 carrier state, and self-ratings.
Results: The elderly marathon group performed better only in one specific cognitive task (the Five Point Test, p = 0.04) and almost significantly better in one additional test (the NAI Stroop Test, p = 0.08). Neither BDNF nor IGF-1 was related to the duration of daily exercise and no differences in the basal levels of these humoral growth factors in the exercise and the control cohort were found. Interestingly, we also found significantly decreased BDNF levels in subjects with Alzheimer's disease in the family in spite of the maintained normal cognitive performance (p = 0.01).
Conclusion: These results suggest that extensive endurance exercise training might be beneficial for maintaining cognitive function in elderly persons. Our data demonstrate that beneficial endurance training effects are not linked to the upregulation of the examined neurotrophins. Since we found reduced BDNF-levels in subjects with a positive family history of Alzheimer's disease, we speculate that BDNF-reduction might precede cognitive impairment.
Trial registration: ClinicalTrials.gov NCT01045031.