Heart Rate Variability Biofeedback (HRVB) is based on breathing at an optimal rate (or resonance frequency, RF) corresponding to the respiratory sinus arrhythmia (RSA). Our aim is to check whether the RF is a stable factor and analyse the HRV parameters individually per each breathing rate, comparing it with free slow breathing. A sample of 21 participants were trained in a test–retest HRVB protocol. The results indicated that RF changed between Test and Retest sessions in 66.7% of participants. This instability could be related to the average of interbeat interval (IBI). HRV time domain parameters (SDNN and RMSSD) were significantly higher for RF than for other breathing rates, including 6 breath/min and free slow breathing. Free slow breathing showed a lower heart rate averages than RF and other slow breathing rates. Overall, our study suggests the relevance of assessing RF individually and before each HRVB session, because the maximum cardiovascular benefits in terms of increasing HRV were found only at RF. Thus, breathing at the individualized and momentary frequency of resonance increases cardiac variability. ; Tis study was supported by "Ministerio de Ciencia e Innovación" of the Spanish Government (Grant number PID2019-107473RB-C2). ; Peer Reviewed ; Postprint (published version)
This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record Armano, Michele, et al. "Spacecraft and interplanetary contributions to the magnetic environment on-board LISA Pathfinder." Monthly Notices of the Royal Astronomical Society 494.2 (2020): 3014-3027. is available online at: https://academic.oup.com/mnras/article-abstract/494/2/3014/5822062?redirectedFrom=fulltext ; LISA Pathfinder (LPF) has been a space-based mission designed to test new technologies that will be required for a gravitational wave observatory in space. Magnetically driven forces play a key role in the instrument sensitivity in the low-frequency regime (mHz and below), the measurement band of interest for a space-based observatory. The magnetic field can couple to the magnetic susceptibility and remanent magnetic moment from the test masses and disturb them from their geodesic movement. LPF carried on-board a dedicated magnetic measurement subsystem with noise levels of 10 nT Hz-1/2 from 1 Hz down to 1 mHz. In this paper we report on the magnetic measurements throughout LPF operations. We characterize the magnetic environment within the spacecraft, study the time evolution of the magnetic field and its stability down to 20 µHz, where we measure values around 200 nT Hz-1/2¿, and identify two different frequency regimes, one related to the interplanetary magnetic field and the other to the magnetic field originating inside the spacecraft. Finally, we characterize the non-stationary component of the fluctuations of the magnetic field below the mHz and relate them to the dynamics of the solar wind. ; This work has been made possible by the LISA Pathfindermission, which is part of the space-science program ofthe European Space Agency. The French contribution hasbeen supported by CNES (Accord Specific de projet CNES1316634/CNRS 103747), the CNRS, the Observatoire deParis and the University Paris-Diderot. E. P. and H. I. wouldalso like to acknowledge the financial support of the Uni-vEarthS Labex program at Sorbonne Paris CiteÌ↪A (ANR-10-LABX-0023 and ANR-11- IDEX-0005-02). The Albert-Einstein-Institut acknowledges the support of the GermanSpace Agency, DLR. The work is supported by the Fed-eral Ministry for Economic Affairs and Energy based on aresolution of the German Bundestag (FKZ 50OQ0501 andFKZ 50OQ1601). The Italian contribution has been sup-ported by Agenzia Spaziale Italiana and Instituto Nazionaledi Fisica Nucleare. The Spanish contribution has been sup-ported by Contracts No. AYA2010-15709 (MICINN), No.ESP2013-47637-P, and No. ESP2015-67234-P (MINECO).M. N. acknowledges support from Fundación General CSIC(Programa ComFuturo). F. R. acknowledges support froma Formación de Personal Investigador (MINECO) contract.The Swiss contribution acknowledges the support of theSwiss Space Office (SSO) via the PRODEX Programme ofESA. L. F. acknowledges the support of the Swiss NationalScience Foundation. The UK groups wish to acknowledgesupport from the United Kingdom Space Agency (UKSA),the University of Glasgow, the University of Birmingham,Imperial College, and the Scottish Universities Physics Al-liance (SUPA). J.I.T. and J.S. acknowledge the support ofthe U.S. National Aeronautics and Space Administration(NASA). ; Peer Reviewed ; Postprint (author's final draft)
