The impact of hydrogen therapies on lower airway dysfunction and exercise performance in recreationally active individuals

Hydrogen (H2) therapies have shown promising antioxidant and anti-inflammatory effects in a range of health conditions, including lower airway dysfunction in animal models. To date, only one study has investigated the effect of H2 gas inhalation in asthmatic patients, yet the prevalence is highest in athletic populations. This thesis aimed to investigate whether H2 gas inhalation and hydrogen-rich water (HRW) could support the management of lower airway dysfunction in recreationally active individuals by attenuating the fall in FEV1 following a eucapnic voluntary hyperpnoea (EVH) challenge and by improving baseline lung function. Chapter 4 compared two EVH challenges performed using a mouthpiece or a face mask. The findings demonstrated that an EVH challenge performed with a face mask can attenuate the fall in FEV1 from baseline in individuals with evidence of hyperpnoea-induced bronchoconstriction compared with completing an EVH challenge with a mouthpiece. Chapter 5 was the first study to investigate the efficacy of H2 gas inhalation using an EVH challenge. The findings suggested that H2 gas inhalation, whether administered pre and/or post EVH challenge, did not attenuate the significant fall in FEV1. Chapter 6 was the first study to explore the effect of HRW in recreationally active males with lower airway dysfunction. A single intake of 1 L of HRW and a 14-day intake (14 L in total) was compared with placebo to investigate the effect on lung function and 5 km cycling time trial performance. There was no significant impact on baseline lung function or exercise performance between experimental conditions. This thesis concluded that in recreationally active individuals with lower airway dysfunction, H2 interventions as administered in this research did not significantly attenuate the fall in FEV1 following an EVH challenge or improve lung function.