Rotorua, hydrogen sulphide and Parkinson's disease-A possible beneficial link?

Rotorua city (New Zealand) is known for its 'rotten egg' smell, due to high levels of hydrogen sulphide (H2S) concentrations emitted from local geothermal vents. Studies have shown H2S as potentially toxic if too high in concentration. However, some health benefits have been observed at lower concentrations. This article summarises what is known about effects of H2S on health and postulates whether ambient air inhalation levels of H2S in Rotorua might have a therapeutic role in the management of motor symptoms in Parkinson's disease (PD).

Chronic H2S inhalation has been shown to have a protective factor on dopaminergic neurons of animal models of PD. A large-scale survey of long-term Rotorua residents showed no evidence of health detriment nor impairment of cognitive functions. Intriguingly, however, participants in higher H2S exposures showed a tendency for faster motor response times in a finger tapping test. One of the PD Motor Rating Scale examination tests for PD is finger tapping speed, as this is associated with motor performance. Might it be that relatively high, but safe, H2S levels in Rotorua could help protect the degradation of dopaminergic neurons associated with PD?

An observed beneficial link between chronic H2S inhalation in PD animal models and improved finger tapping scores in a sample of the Rotorua population, linked to dopaminergic nerve function, is worth investigating further.