Effects of respiratory and applied muscle tensing interventions on responses to a simulated blood draw among individuals with high needle fear.

Fear of blood and needles increases risk for presyncopal symptoms. Applied muscle tension can prevent or attenuate presyncopal symptoms; however, it is not universally effective. This study examined the effects of applied muscle tension, a respiratory intervention, and a no treatment control condition, on presyncopal symptoms and cerebral oxygenation, during a simulated blood draw with individuals highly fearful of needles. Participants (n = 95) completed questionnaires, physiological monitoring, and two trials of a simulated blood draw with recovery. Presyncopal symptoms decreased across trials; however, no group differences emerged. Applied muscle tension was associated with greater cerebral oxygenation during trial two, and greater end-tidal carbon dioxide during both trials. The respiratory intervention did not differ from the no treatment control. Applied muscle tension is an intervention that can increase cerebral oxygenation and end-tidal carbon dioxide. While the respiratory intervention is promising within therapeutic settings, it was not efficacious after a brief audio training.