Autonomic neural activity in male human subjects during different phases of synodic period of moon

The gravitational pull of moon on earth is different in new moon (NM), first quarter (FQ), full moon (FM), and third quarter (TQ) and the amplitude of ocean tide also differs according to the phases of synodic period of moon. In the present study, Valsalva maneuver was performed for the measurement of Valsalva ratio (VR), tachycardia ratio (TR), and bradycardia ratio (BR) in 32 male university students (age: 23.7 ± 1.9 years) to explore the autonomic neural activity during those four specific phases. It was found that the VR was significantly higher and BR was significantly lower in NM and FM compared to FQ and TQ. But the TR did not differ significantly during different phases of lunar month. It appears from this study that there is a circalunar periodicity of autonomic neural activity of human which is efficiently adjusted during NM and FM in comparison to FQ and TQ.