Cerebral and Central Hemodynamic Responses to Cognitive Stimulation Versus High-Intensity Exercise in Healthy Adults

Background: Central and cerebral hemodynamic responses increase during both cognitive stimulation and physical exercise. Cognitive tasks elicit modest increases in cerebral blood flow through neurovascular coupling, whereas high-intensity exercise induces larger systemic and cerebrovascular responses due to increased cardiac output, arterial pressure, and metabolic demand. However, few studies have directly compared the magnitude of hemodynamic change between these two physiologically distinct stimuli. Accordingly, we compared the magnitude of central and cerebral hemodynamic responses to a brief cognitive task and a short bout of high-intensity exercise. We hypothesized that both stimuli would increase central and cerebral hemodynamics, with exercise producing greater responses than cognitive stimulation. Methods: Healthy adults (n=32; BMI: 26.1 ± 5.1 kg/m 2 ; age: 34.8 ± 15.3 yrs) completed both a cognitive task (single letter cancellation test, SLCT) and a single bout of high-intensity exercise (HIE; cycle ergometer increasing by 50 W/min to tolerance or 80% of age-predicted max heart rate) in a randomized, crossover design during a single study visit. Hemodynamic monitoring included continuous measurements of heart rate (HR) via three-lead ECG, mean arterial pressure (MAP), and stroke volume (SV) via finger photoplethysmography. Middle cerebral artery (MCA) blood velocity was measured by transcranial Doppler ultrasound (2-MHz). End-tidal CO 2 (etCO 2 ) and respiratory rate (RR) were measured via oral/nasal cannula (CO2100C Gas Analyzer, BIOPAC). Cardiac output (Q), cerebrovascular resistance (CVR), and systemic vascular resistance (SVR) were calculated as: Q=HR×SV, SVR=MAP/Q, and CVR=MAP/mean MCA velocity. Hemodynamic responses were measured as percent change from baseline (%Δ) and compared between conditions via paired t-test. Results: There were differences in hemodynamic responses between the cognitive task and HIE: %Δ HR (SLCT: 15.6 ± 13.6 vs HIE: 136.7 ± 49.9; p< 0.001), %Δ SV (SLCT: 6.3 ± 13.6 vs HIE: 45.7 ± 26.4; p< 0.001), %Δ Q (SLCT: 22.5 ± 20.9 vs HIE: 236.6 ± 85.4; p< 0.001), %Δ MAP (SLCT: 7.4 ± 14.5 vs HIE: 41.5 ± 26.4; p< 0.001), %Δ RR (SLCT: 57.6 ± 52.3 vs HIE: 136.5 ± 92.7; p< 0.001), %Δ SVR (SLCT: -8.1 ± 13.4 vs HIE: -54.1 ± 12.3; p< 0.001), and %Δ etCO 2 (SLCT: -1.0 ± 9.1 vs HIE: -14.8 ± 23.7; p=0.01). %Δ MCA mean velocity was greater following HIE compared to the cognitive task (SLCT: 15.8 ± 10.7 vs HIE: 24.0 ± 20.5; p=0.04). Notably, %Δ CVR decreased during the cognitive task but increased during HIE (SLCT: -6.5 ± 14.6 vs HIE: 16.6 ± 26.4; p< 0.001). Conclusions: Both cognitive stimulation and high-intensity exercise increased MCA velocity, supporting our hypothesis; however, exercise produced significantly larger responses in all central hemodynamic variables (HR, SV, Q, MAP) and MCAv. Notably, the cognitive task increased MCAv despite minimal central hemodynamic changes and was accompanied by decreased CVR, suggesting that cerebral hemodynamic responses to cognitive stimulation occur primarily through local neurovascular coupling (cerebral vasodilation). In contrast, exercise-induced increases in MCAv occurred alongside increased CVR, indicating that elevated perfusion pressure rather than vasodilation drove the cerebral blood flow response. Future research should examine whether combined cognitive tasks amplify neurovascular coupling responses and whether these response patterns differ in aging or clinical populations. Funding: This work was supported by Dr. Rosenberg’s startup grant from Midwestern University. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.