Premium
Blood flow restricted resistance exercise and reductions in oxygen tension attenuate mitochondrial H 2 O 2 emission rates in human skeletal muscle
Author(s) -
Petrick Heather L.,
Pignanelli Christopher,
Barbeau PierreAndre,
ChurchwardVenne Tyler A.,
Dennis Kaitlyn M. J. H.,
Loon Luc J. C.,
Burr Jamie F.,
Goossens Gijs H.,
Holloway Graham P.
Publication year - 2019
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jp277765
Subject(s) - reactive oxygen species , mitochondrial ros , bioenergetics , skeletal muscle , mitochondrion , oxygen tension , oxidative stress , oxygen , chemistry , oxidative phosphorylation , medicine , endocrinology , biology , biochemistry , organic chemistry
Key points Blood flow restricted resistance exercise (BFR‐RE) is capable of inducing comparable adaptations to traditional resistance exercise (RE), despite a lower total exercise volume. It has been suggested that an increase in reactive oxygen species (ROS) production may be involved in this response; however, oxygen partial pressure ( P O 2 ) is reduced during BFR‐RE, and the influence of P O 2on mitochondrial redox balance remains poorly understood. In human skeletal muscle tissue, we demonstrate that both maximal and submaximal mitochondrial ROS emission rates are acutely decreased 2 h following BFR‐RE, but not RE, occurring along with a reduction in tissue oxygenation during BFR‐RE. We further suggest that P O 2is involved in this response because an in vitro analysis revealed that reducing P O 2dramatically decreased mitochondrial ROS emissions and electron leak to ROS. Altogether, these data indicate that mitochondrial ROS emission rates are attenuated following BFR‐RE, and such a response is likely influenced by reductions in P O 2 .Abstract Low‐load blood flow restricted resistance exercise (BFR‐RE) training has been proposed to induce comparable adaptations to traditional resistance exercise (RE) training, however, the acute signalling events remain unknown. Although a suggested mechanism of BFR‐RE is an increase in reactive oxygen species (ROS) production, oxygen partial pressure ( P O 2 ) is reduced during BFR‐RE, and the influence of O 2 tension on mitochondrial redox balance remains ambiguous. We therefore aimed to determine whether skeletal muscle mitochondrial bioenergetics were altered following an acute bout of BFR‐RE or RE, and to further examine the role of P O 2in this response. Accordingly, muscle biopsies were obtained from 10 males at rest and 2 h after performing three sets of single‐leg squats (RE or BFR‐RE) to failure at 30% one‐repetition maximum. We determined that mitochondrial respiratory capacity and ADP sensitivity were not altered in response to RE or BFR‐RE. Although maximal (succinate) and submaximal (non‐saturating ADP) mitochondrial ROS emission rates were unchanged following RE, BFR‐RE attenuated these responses by ∼30% compared to pre‐exercise, occurring along with a reduction in skeletal muscle tissue oxygenation during BFR‐RE ( P < 0.01 vs . RE). In a separate cohort of participants, evaluation of mitochondrial bioenergetics in vitro revealed that mild O 2 restriction (50 µ m ) dramatically attenuated maximal (∼4‐fold) and submaximal (∼50‐fold) mitochondrial ROS emission rates and the fraction of electron leak to ROS compared to room air (200 µ m ). Combined, these data demonstrate that mitochondrial ROS emissions are attenuated following BFR‐RE, a response which may be mediated by a reduction in skeletal muscle P O 2 .