Rojas Vega S; German Sport University Cologne, Germany,
Solera-Herrera A; Vafa R; Acero-Moreno D; et al

Journal of Diabetes Research. 2026(1):e1311227, 2026.

BACKGROUND: Diabetes is associated with an increased risk of cognitive
dysfunction. We are aimed at examining cognitive performance in people
with Type 2 diabetes mellitus (T2DM) and their correlation with physical
activity (PA)/fitness level and mood.

METHODS: A cross-sectional study involving 47 individuals with T2DM, 30
diabetes-free individuals (controls): ages of 40-65 years and without
dementia. Subjects were evaluated using a neuropsychological test battery
that included Stroop, VLMT, CORSI, TMT and neuropsychiatric scales. The
Global Physical Activity Questionnaire (GPAQ) was assessed. Physical
fitness was evaluated using a maximal cardiopulmonary exercise testing
(CPX).

RESULTS: Compared with controls, people with T2DM had lower
cardiorespiratory fitness (CRF) and more frequent cognitive performance
below 1 SD of the normative value. Those individuals with T2DM, who
displayed low fitness, showed significantly poorer cognitive inhibition
(Stroop, p < 0.001), processing speed (TMT-A, p < 0.001), cognitive
flexibility (TMT-B, p < 0.001), visuospatial memory (CORSI, p < 0.001) and
memory consolidation (VLMT, p < 0.001). Higher ventilatory and metabolic
CRF markers and higher PA levels correlated significantly with higher
cognitive performance. None of the neuropsychological or psychiatric
background variables correlated significantly with any of the cognitive
scales.

CONCLUSIONS: Individual CRF markers and PA levels correlated positively
with cognitive performance in people with T2DM and in nondiabetic
individuals. However, individuals with T2DM showed at least two to three
times more frequent cognitive performances more than 1 SD below norm as
compared with controls. Among people with T2DM, those with low aerobic
fitness/PA levels showed significantly lower cognitive performance,
especially in the attention-concentration, executive functioning, episodic
memory and visuospatial processing domains.