Does mental fatigue pose a risk in older age? The effectiveness of combined training as a solution

Introduction: Mental fatigue, caused by cognitive/emotional efforts that are inherent to daily life activities, impairs performance and predisposes people to health problems. Although older people may be more vulnerable to mental fatigue, there are many gaps in the literature. Objectives: This study aimed to clarify the effects of mental fatigue in ageing, to test the moderating role of cognitive decline and Brain Endurance Training for its prevention in ageing. Thirty people aged 65 to 76 years (17 women, 13 men), sedentary but without severe physical or mental illness, participated in the study. Material and method: Based on their results in the Mini-Mental State Examination, and normative scores, they were divided into 2 groups: Low Cognitive Impairment (≥ 25 points) and Medium (≤ 24 and ≥ 21). Subsequently, 2 sessions were conducted in counterbalanced order, where physical (Chair-stand test, Arm-curl test, Walking test, RPE) and cognitive (Psychomotor Vigilance Test and Incongruent Stroop) performance, and mental fatigue (Visual Analogue Scale) were measured, after 20 min. of documentary (control condition, rest) or Time Load Dual Back (experimental condition, mental fatigue). Then, a 2-month intervention (3 trainings/week) with Brain Endurance Training was performed on 12 subjects (7 women, 5 men) with medium cognitive impairment. Results: The results show that mental fatigue worsens performance and increases health risks, especially in people with cognitive impairment. Brain Endurance Training appears to be effective in counteracting the effects of mental fatigue in ageing. Conclusions: To conclude, mental fatigue has clinical considerations in ageing. Then, it is recommended to quantify it and promote active ageing for its prevention/mitigation.