Effectiveness of emWave Biofeedback in Improving Heart RateVariability Reactivity to and Recovery from Stress

The  current  study examined  the  efficacy  of heart rate variability (HRV) biofeedback using emWave, a publicly  available  biofeedback  device,  to  determine  whether   training   affected   physiological   tone and   stress responses.   Twenty-seven   individuals   aged   18–30 years were  randomized  to  a  treatment  or  no-treatment  controlgroup.  Treatment  participants  underwent  4–8  sessions  of emWave intervention,  and  all  participants  attended  pre-treatment  and  post-treatment  assessment  sessions  during which  acute  stressors  were  administered.  Physiological data  were  collected  at  rest,  during  stress,  and  following stress. emWavetreatment  did  not  confer  changes  in  tonicmeasures  of  HRV  or  in  HRV  recovery  following  stress. However,  treatment  participants  exhibited  higher  para-sympathetic  responses  (i.e.,  pNN50)  during  stress  presentations  at  the  post-treatment  session  than  their  control counterparts.  No  treatment  effects  were  evident  on  self-reported  measures  of  stress,  psychological  symptoms,  or affect. Overall, results from the current study suggest that the emWave may confer some limited treatment effects by increasing   HRV during   exposure   to   stress.   Additional development and testing of the emWave treatment protocol is necessary before it can be recommended for regular use in  clinical  settings,  including  the  determination  of  what physiological  changes  are  clinically  meaningful  during HRV biofeedback training.

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