DOI: 10.5061/dryad.9ghx3ffwv
title: Sixty-minute inhalation of molecular hydrogen decreases blood oxygen saturation but does not alter autonomic cardiac regulation at rest in healthy females: A randomized, double-blind, placebo-controlled crossover study

description: This randomized, double-blind, placebo-controlled crossover study
 investigated the effects of 60-minute molecular hydrogen inhalation on
 oxygen saturation and heart rate variability in healthy females. Twenty
 physically active participants completed two inhalation sessions with
 either molecular hydrogen or placebo (ambient air), separated by a
 seven-day washout period. Oxygen saturation and heart rate variability
 were monitored during 60 minutes of inhalation. The dataset contains basic
 anthropological characteristics of participants. The oxygen saturation
 value represents the average value taken from a 5-minute segment. The
 heart rate variability values represent the time- and frequency-domain
 indices calculated from a 5-minute segment.
description: Experimental protocol The research was
 conducted as a randomized, double-blind, placebo-controlled crossover
 study. Twenty physically active female sports science students years were
 divided randomly into two experimental groups. One group inhaled molecular
 hydrogen and the other group inhaled a placebo for 60 minutes. Following a
 seven-day washout period, a second experimental session was conducted
 where molecular hydrogen and placebo inhalation were reversed. Molecular
 hydrogen (flow of 300 ml/min, purity of 99.8%) was produced by a generator
 i300 (Molecular Hydrogen Medical Technologies, Ostrava, Czech Republic).
 Placebo was delivered using a modified generator that pumps ambient air.
 Participants were seated and a chest strap (Polar Pro Strap, Polar,
 Kempele, Finland) was placed. A pulse oximeter sensor was placed on right
 index finger. They were then fitted with a nasal cannula supplying
 molecular hydrogen or placebo. Subsequently, SpO<sub>2</sub>
 and ECG signal were recorded for 60 minutes in an inactive seated
 position. Anthropometric measurement
 Body mass and body fat were measured using bioimpedance analysis
 (Tanita MC-980 MA, Tanita, Tokyo, Japan). Body height was measured using a
 stadiometer (SOEHNLE 7307, Leifheit, Nassau, Germany).
 Oxygen saturation measurement
 SpO<sub>2</sub> was measured with sampling frequency
 of 1.0 Hz using a Nonin Avant 2120 pulse oximeter (Nonin Medical,
 Minneapolis, MN, USA). The 60-minute recording was divided into 12
 segments lasting 5 minutes and the average value was calculated for each
 segment. Heart rate variability measurement
 RR intervals were measured using the DiANS PF8 diagnostic system
 (DIMEA Group, Olomouc, Czech Republic). The 60-minute recording was
 divided into 12 segments lasting 5 minutes. Time-domain indices included
 RMSSD and SDNN. Spectral analysis was based on fast Fourier transform and
 processed from a set of 300 consecutive artifact-free RR intervals
 extracted from each 5-minunte segment. Two frequency bands were used: 0.05
 to 0.15 Hz for LF, and 0.15 to 0.50 Hz for HF.
description: # Sixty-minute inhalation of molecular hydrogen decreases blood oxygen
 saturation but does not alter autonomic cardiac regulation at rest in
 healthy females: A randomized, double-blind, placebo-controlled crossover
 study Dataset DOI:
 [10.5061/dryad.9ghx3ffwv](https://doi.org/10.5061/dryad.9ghx3ffwv) ##
 Description of the data and file structure The dataset is stored in a
 single Excel file with two lists. The list titled “Participants” contains
 the anthropological characteristics of the participants. The list titled
 “Experiment” contains values from two experimental sessions. ### Files and
 variables ### File: raw_data.xlsx #### List "Participants" #####
 Variables * "Participant": anonymized label for each
 participant. * "Inhalation": type of inhalation in the first
 session. H2 means molecular hydrogen, Pla means placebo. The inhalation is
 reversed in the second session. * "Body mass": body mass in kg.
 * "Body fat": body fat percentage determined by bioimpedance
 analysis. #### List "Characteristics" ##### Variables Basic
 statistical characteristics (minimum value, maximum value, mean and
 standard deviation) relating to the age and body height of participants
 are provided. #### List "Experiment" ##### Variables *
 "Participant": anonymized label for each participant. *
 "Session": Session 1 means the first session; the inhalation
 used can be found in the "Inhalation" variable in the
 Participants list. Session 2 means the second session measured after a
 one-week washout period; the inhalation is the opposite of the inhalation
 used in the first session. * "Window": denotes each of the
 twelve segments lasting 5 minutes. The total duration is 60 minutes. *
 "N of artifacts": Number of artifacts removed from the segment.
 * "SpO2": blood oxygen saturation in percent. * "RR":
 duration of RR interval in ms. * "RMSSD": square root of the
 mean of the squares of the successive differences between RR intervals in
 ms. * "SDNN": standard deviation of RR intervals in ms. *
 "LF": low-frequency power in ms squared. * "HF":
 high-frequency power in ms squared. ## Human subjects data All
 participants signed informed consent in which they agreed to the public
 sharing of de-identified data. Values that could identify a participant
 were removed from the dataset.