The socially evaluated handgrip test: Introduction of a novel, time-efficient stress protocol

Abstract

Most widely-used stress-induction procedures (such as the TSST and the Cold Pressor Test) require considerable effort and overhead in terms of preparation, logistics, and staff recruitment. Moreover, while known to reliably induce HPA axis activation, especially when combined with social self-threat, most conventional laboratory stressors cannot be flexibly adapted to elicit either a mainly autonomic or an additional endocrine stress response. Being a promising alternative approach, a new version of the isometric handgrip test enriched by a social-evaluative component was evaluated in the present study. On two consecutive sessions, forty participants (20 women) performed a handgrip task at both 45% (stress) and 10% (control) of maximum voluntary isometric contraction lasting for 3min. During the stress test, continuous visual feedback on performance was given. Participants in the social-evaluative condition (50%) were observed and evaluated by a previously unknown person of the opposite sex, whereas in the standard condition feedback was provided via a computer monitor. Cardiovascular measures (heart rate, blood pressure) as well as additional indices of autonomic reactivity (skin conductance, heart-rate variability) were registered before, during, and after stress induction. Moreover, changes in salivary cortisol and in subjective well-being were assessed. Relative to control, significant increases in cardiovascular and sympathetic activity were found, irrespective of experimental group. Importantly, however, additional social evaluation resulted in elevated cortisol levels. Furthermore, evidence for reduced vagal tone during sustained socially evaluated handgrip emerged. In conclusion, the socially evaluated handgrip test represents a versatile, time-efficient method to induce stress in small laboratory settings.

Keywords: Autonomic nervous system; Cortisol; Handgrip; Social evaluation; Stress.