Heart rate variability (HRV) and vagal tone have been long been known to be affected by emotions and psychological well-being [1]. Of interest is the fact that there seems to be a gap in our knowledge of the effect of the emotion of love/affection on HRV [2]. Our aim was to investigate the short term effect of love on HRV in healthy subjects. 61 healthy volunteers underwent consecutive five-minute HRV measurements. Subjects were all staff and students of the Arabian Gulf University (AGU). The study was given ethical approval by the Research and Ethics committee, College of Medicine & Medical Sciences, AGU. All participating subjects gave informed and signed consent. Subjects were supine and tests were separated by several minutes. An ECG lead was attached to each limb. LabChart software and a PowerLab were used for data acquisition. We have previously shown a significant decrease in heart rate over three consecutive tests [3], so experiments were conducted after a baseline heart rate plateau was reached. The order of the experiments was: control, deep breathing (9-10 breaths min-1) and emotional questionnaire participation. The questionnaire was composed of 15 questions of the Sternberg’s love scale [4]. A sub-set of subjects (n=20) also completed a fourth dummy questionnaire test. Data was also normalised by taking into account the heart rate [5]. The results were analysed by repeated measures ANOVA. p < 0.017 was considered as significant. The subjects’ mean (± S.D.) age was 26.3 ± 11.3 years and mean BMI was 26.1 ± 5.3 kg m-2. Mean heart rate (± SD) showed a borderline change for the 1st vs. 3rd test (74.1 ± 9.7 beats min-1 vs. 75.6 ± 10.7 beats min-1; p=0.0024). Deep breathing was significantly higher than control and the emotional test for total frequency, low frequency (LF), LFnu, SDNN, SD1 and SD2. Deep breathing was also significantly lower for high frequency (HF) nu. With respect to the emotional test, LFnu was significantly higher than control (p=0.012), and HFnu was significantly lower than control (p=0.0002). Similar findings were found with the normalised data. The most important finding from our study is that the emotional testing did cause a borderline increase in heart rate and an increase of LFnu, which reflects parasympathetic and sympathetic stimulation and a fall in HFnu, reflecting decreased parasympathetic stimulation. This suggests an overall increase in sympathetic output. Previous work suggests love might decrease heart rate [2]. Analysis of the dummy questionnaire will strengthen our argument. As the emotional questionnaire gave us a numerical value, we plan to compare this to our control data, to see if there could be a long term effect on HRV. Implications of this work include the possibility love can act as a cardiovascular stressor.