The study is the first to report fatigue-related differences in brain activation across the lifespan and by sex, during a cognitively strenuous task. Thus, the study measures the fatigue at a given moment “fatigue state” and the measurement over a longer period, fatigue as a “trait”. The “state” measure of fatigue assesses a subject’s instantaneous experience of fatigue at the time of the test; The “trait” measure of fatigue assesses the amount of fatigue felt by a subject over a longer period, here during the previous 4 weeks.
The study: to study the relationship between age and fatigue, the researchers used neuroimaging and self-report data. The researchers collected the data of fatigue felt and experienced by 43 participants, men and women, in good health and aged 20 to 63 years. The state of fatigue was measured during fMRI examinations during a cognitively stimulating task. Neuroimaging data show that:
- activation of the middle frontal areas of the brain changes with age;
- younger people seem to use these areas to fight fatigue, but older people don’t;
women show greater resilience in the face of a tiring task.
These initial differences provide a better understanding of previous studies conducted on fatigue, both by evaluating the 2 types of fatigue and also the response to fatigue according to age and sex.