Effects of aerobic training and cognitive stimulation on cortisol levels and behavioral disorders in patients with Alzheimer’s disease

Aim: Sundowning syndrome (SDS) in individuals with Alzheimer’s disease (AD) is a clinical phenomenon characterized by the intensification of neuropsychiatric symptoms during the sunset. Currently, there are no specific treatments for SDS, but recent literature reported a strong relationship between high levels of cortisol and SDS symptoms. Both aerobic training (AT) and cognitive stimulation (CS) are capable to reduce the level of cortisol. However, it is not clear if SDS symptoms would benefit from AT and CS. Therefore, the aim of this study was to evaluate the effects of AT and CS as potential treatments of SDS. The combination effects of AT and CS (AT+CS) was also assessed. Methods: Twenty-nine patients with advanced AD (clinical dementia rating, CDR: 2) were randomly assigned to: CS group, which was treated with a cognitive stimulation; AT group, treated with aerobic training; CS+AT group, which performed both AT and CS. All groups were compared with age-matched controls (CTRL). All treatments were performed 5 days a week, for 2 months, one hour before the sunset. Salivary levels of cortisol were collected 5 times a day before and after treatments, together with behavioral disorders and cognitive dysfunction tests (Mini-Mental State Examination (MMSE), Neuropsychiatric Inventory (NPI) and Agitated Behavior Scale (ABS)). Results: Daily salivary levels of cortisol in AT and CS+AT groups decreased significantly by ~50%. Behavioral disorders reduced by ~50% in AT and CS+AT groups. Cognitive dysfunction was stable in all groups without significant changes. Conclusions: The main outcome of this study was that a program of AT or the combination of AT and CS decreased the salivary levels of cortisol. Interestingly, SDS symptoms also decreased to a similar extent in the same groups, suggesting a possible neuro-endocrinal pathway associated with these interventions.