Lackner, Helmut Karl Goswami, Nandu Papousek, Ilona Roessler, Andreas Grasser, Erik Konrad Montani, Jean-Pierre Jezova, Daniela Hinghofer-Szalkay, Helmut 2009-11-29 Cardiovascular responses to single stressors diminish over time. Interaction of different stressors influencing hemodynamic variables, indicative of stress-induced reactivity and physiological responses are, however, poorly understood. We investigated time course of mental (using mental arithmetic, MA) and orthostatic (using head up tilt, HUT) challenges induced responses in 16 males. Three protocols were used: HUT, MA and MA + HUT, with sessions randomized and two weeks apart. Hemodynamic responses were compared for 30 s epochs of stress application (stress_T1, stress_T2…). Compared to baseline, HUT, HUT + MA and MA applications affected heart rate (HR) (+ 15.1 ± 8.0 bpm, + 20.0 ± 9.2 bpm, + 11.9 ± 7.2 bpm, all <i>p</i>'s < .001, respectively) and stroke volume (SV) (− 22.3 ± 8.1 ml, − 22.0 ± 10.4 ml, − 7.6 ± 8.7 ml, all <i>p</i>'s < .001, respectively). HUT and MA + HUT induced HR increases were higher in stress_T2 compared to stress_T1 (<i>p</i> < .05) and reached maximum at stress_T2. HUT and MA + HUT further reduced SV in stress_T2 as compared to stress_T1 (<i>p</i> < .001); lowest SV was in stress_T2. Mean arterial pressure reached its minimum in stress_T1 during HUT and MA + HUT (− 6.0 ± 8.5 mm Hg, <i>p</i> < .001, − 4.4 ± 9.7 mm Hg, <i>p</i> < .01, respectively) but increased in MA (+ 4.3 ± 3.7 mm Hg, <i>p</i> < .01). Combination of MA + HUT resulted in different time courses of blood pressure responses as compared to HUT alone. We conclude that application of single or combined stress challenges lead to stressor- and time dependent-initial changes in cardiovascular responses. Our findings provide novel insights regarding the duration a stressor must be applied to elicit maximal cardiovascular responses. application/pdf https://folia.unifr.ch/global/documents/301217 https://folia.unifr.ch/documents/301217/files/montani_tcc.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1016/j.ijpsycho.2009.11.003 info:eu-repo/semantics/openAccess License undefined International Journal of Psychophysiology. - 2010, vol. 75, no. 1, p. 48-53 Mental arithmetic Head up tilt Cardiovascular reactivity Time course Habituation Blood pressure Heart rate info:eu-repo/classification/udc/57 Time course of cardiovascular responses induced by mental and orthostatic challenges http://purl.org/coar/resource_type/c_6501