Abstract
Several brands of water enriched with O2 (O2-waters) are commercially available and are advertised as wellness and fitness waters with claims of physiological and psychological benefits, including improvement in exercise performance. However, these claims are based, at best, on anecdotal evidence or on a limited number of unreliable studies. The purpose of this double-blind randomized study was to compare the effect of two O2-waters (~110 mg O2·L−1) and a placebo (10 mg O2·L−1, i.e., close to the value at sea level, 9–12 mg O2·L−1) on the cardiopulmonary responses and on performance during high-intensity exercise. One of the two O2-waters and the placebo were prepared by injection of O2. The other O2-water was enriched by an electrolytic process. Twenty male subjects were randomly allocated to drink one of the three waters in a crossover study (2 L·day−1 × 2 days and 15 mL·kg−1 90 min before exercise). During each exercise trial, the subjects exercised at 95.9 ± 4.7% of maximal workload to volitional fatigue. Exercise time to exhaustion and the cardiopulmonary responses, arterial lactate concentration and pH were measured. Oxidative damage to proteins, lipids and DNA in blood was assessed at rest before exercise. Time to exhaustion (one-way ANOVA) and the responses to exercise (two-way ANOVA [Time; Waters] with repeated measurements) were not significantly different among the three waters. There was only a trend (p = 0.060) for a reduction in the time constant of the rapid component of VO2 kinetics with the water enriched in O2 by electrolysis. No difference in oxidative damage in blood was observed between the three waters. These results suggest that O2-water does not speed up cardiopulmonary response to exercise, does not increase performance and does not trigger oxidative stress measured at rest.
Highlights
This article is an open access articleAt equilibrium with partial pressure at sea level (PO2 ~160 mmHg) and for temperature ranging between 10 and 25 ◦ C, the amount of O2 dissolved in water ranges respectively between 12 and 9 mg·L−1 [1] (Box 1)
As discussed by the authors, it is difficult to speculate about the physiological significance of these changes, their possible effects on performance and how they could be related to ingestion of the O2 -water, but these findings suggest that O2 -waters could modify the cardiopulmonary response to exercise
Ters
Summary
At equilibrium with partial pressure at sea level (PO2 ~160 mmHg) and for temperature ranging between 10 and 25 ◦ C, the amount of O2 dissolved in water ranges respectively between 12 and 9 mg·L−1 [1] (Box 1). Relationship between PO2 and temperature, and O2 content of water according to Henry’s law [1] expressed in various units: mol·L−1 , mL·L−1 , mg·L−1 and ppm, at sea level, 10 ◦ C and dry air. The amount of O2 dissolved in water (mol·L−1 ) depends on the temperature (T in K = T[◦ C] + 273) and PO2 (in atmosphere: atm) and is described by Henry’s law where 769.23 and 1700 are Henry’s constants for O2 : O2 content (mol·L−1 ) = PO2 (atm)/{769.23 × exp [−1700 × (1/T − 1/298)}
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