Objectives: Warm physical contact may positively influence our health and well-being; however, it has not been investigated yet whether serum proteins are influenced by warm physical contact in healthy couples. In this study, we focused on psychological and physiological effects of warm partner contact in healthy couples.
Methods: When participants freely kissed and hugged their romantic partners, they were asked to subjectively evaluate their present emotions. Furthermore, changes of serum proteins were determined by using ProteinChip surface enhanced laser desorption/ionization-time-of-flight-mass spectrometry (SELDI-TOF-MS). We characterized these proteins by using biochemical techniques combined with gel filtration high performance liquid chromatography (HPLC), reverse-phase HPLC, and sequencing analyses.
Results: Romantic couples became happier and less irritated after kissing and hugging. Accompanying these psychological changes, SELDI-TOF-MS indicated that the intensities of 66-k Da, 11.7-k Da, and 5.9-k Da serum proteins were increased. These proteins were identified as serum albumin and beta2-microglobulin, and probably fibrinogen fragment. The feeling of happiness positively correlated and the feeling of irritation negatively correlated with intensities of serum albumin and beta2-microglobulin.
Conclusion: These results suggest that psychological stress may be reduced and we may feel happiness when we kiss and hug a romantic partner. Furthermore, these results also suggest that warm partner contact influences peripheral circulating proteins, more importantly, may promote health and well-being.