Similarities and differences in carotid artery, hemodynamic, and autonomic reactivity induced by mental stress or...

The cold pressor test (CPT) is used to investigate cardiovascular and autonomic responses, while the Stroop color-word test (Stroop) is also used for this purpose, although its vascular effects require further understanding. This randomized crossover study compared vascular, hemodynamic, and autonomic responses induced by cold and mental stress. Twenty participants (10 females; 25.7 ± 5.2 years) underwent the Stroop and CPT. Carotid artery reactivity (CAR) was evaluated using ultrasound. Arterial pressure (AP), heart rate (HR), and R-R intervals (RRi) were continuously recorded. RRi were used to infer autonomic modulation through HR variability. Parametric data are reported as mean ± SD and non-parametric data as median (p25-p75). CAR magnitude did not differ between tests (Stroop: 2.8 ± 3.6; CPT: 4.1 ± 4.2%; p = 0.236), although Stroop elicited a shorter time to peak (66.5 ± 56.5 vs. 99.5 ± 35.1 s; p = 0.020). CPT induced a greater rise in diastolic AP (Stroop: 8.5 (6.2-10.0); CPT: 13.0 (6.2-23.5) mmHg; p = 0.009) and mean AP (Stroop: 8.4 ± 4.2; CPT: 13.5 ± 8.5 mmHg; p = 0.023). Stroop produced a larger HR increase (20.5 (10.2-27.7) vs. 11.0 (5.2-14.7) bpm; p = 0.013) and larger decrease in parasympathetic modulation (RMSSD - Stroop: -21.3 (-39.6 to -10.0); CPT: -12.8 (-22.8 to 0.95) ms; p = 0.026; HF - Stroop: -2.3 ± 1.3; CPT: -0.61 ± 0.74 Ln ms²; p < 0.001). In summary, Stroop evoked a CAR similar in magnitude to CPT, but with an earlier peak, supporting anticipatory physiological adjustments to mental stress.