This pilot study aimed to evaluate the autonomic nervous system (ANS) disturbance before, during and after a cell phone call, in healthy adults. The opted ANS biomarker was heart rate variability (HRV), as it has been previously related to cardiovascular morbidity, mortality and depression.

Twenty-four healthy volunteers (aged 34.5±11.5y) entered this prospective study, after providing written informed consent. Their characteristics are presented in Table 1. All were free of medication and underwent measurement of linear HRV parameters (RRI, LF, HF, LF/HF, SDNN, SDANN, NN50, RMSSD) with CNS Task Force Monitor in supine position, in the cardiovascular lab, in the same time of the day (15.30–16.30). Measurements were recorded during baseline relaxation (15min), while speaking on their own cell phone (5min) and after cell phone call end (20min) (Fig. 1). Alterations along the successive phases were statistically evaluated with repeated measures analysis in SPSS 17.

Only mean sinus rhythm of RR intervals was significantly changed (P<0.01). This finding persisted during the 20minutes of relaxation period following call.

Even a 5minute call causes a subtle but persisting response of HRV. This study may stimulate further research on cell phone use impact on healthy and patient subjects.