Although activities of daily living often involve performing a stressful cognitive task simultaneously with a motor task, it is not well understood whether vascular tone and the control of force under these stressful conditions differ from tasks performed in isolation (i.e., without the cognitive task) in males and females. Our goal was to determine the impact of performing a difficult cognitive task simultaneously with a handgrip task on forearm vascular conductance and force steadiness. 15 males (19-30 years) and 15 females (18-30 years) performed isometric contractions at 5, 10 and 20% of Maximal Voluntary Contraction (MVC) in the presence and absence of a difficult math task (subtractions by 13). Mental math reduced force steadiness particularly at 5%, but not 10% and 20% of MVC (Δ: 0.8 ± 0.2 vs 0.2 ± 0.1 vs 0.01 ± 0.1% respectively, session × intensity: P = 0.017) for males and females (session × intensity × sex: P = 0.666). Vascular conductance relative to lean mass was reduced in the presence of mental math at lower contraction intensities (Δ: 0.47 ± 0.2 vs 0.46 ± 0.2 vs 0.12 ± 0.2 mL × min -1 × Kg -1 1 × mmHg for 5, 10 and 20% MVC, respectively; session × intensity: P = 0.039), and the reductions were negatively associated with MVC. Although males and females had similar reductions in force steadiness in the presence of mental math, individuals with lower MVC, often females, were more likely to show reductions in vascular conductance in the presence of cognitive stress.
Pereira et al. (Thu,) studied this question.