Determinants of the maximal functional reserve during repeated supramaximal exercise by humans: The roles of Nrf2/Keap1, antioxidant proteins, muscle phenotype and oxygenation
Victor Galvan-Alvarez,
Marcos Martin-Rincon,
Angel Gallego-Selles,
Miriam Martínez Canton,
NaDer HamedChaman,
Miriam Gelabert-Rebato,
Mario Perez-Valera,
Eduardo García-Gonzalez,
Alfredo Santana,
Hans-Christer Holmberg,
Robert Boushel,
Jostein Hallén,
Jose A.L. Calbet
Affiliations
Victor Galvan-Alvarez
Department of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, 35017, Spain; Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Paseo Blas Cabrera Felipe ''Físico'' s/n, 35017, Las Palmas de Gran Canaria, Spain
Marcos Martin-Rincon
Department of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, 35017, Spain; Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Paseo Blas Cabrera Felipe ''Físico'' s/n, 35017, Las Palmas de Gran Canaria, Spain; Corresponding author. Department of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, 35017, Spain.
Angel Gallego-Selles
Department of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, 35017, Spain; Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Paseo Blas Cabrera Felipe ''Físico'' s/n, 35017, Las Palmas de Gran Canaria, Spain
Miriam Martínez Canton
Department of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, 35017, Spain; Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Paseo Blas Cabrera Felipe ''Físico'' s/n, 35017, Las Palmas de Gran Canaria, Spain
NaDer HamedChaman
Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Paseo Blas Cabrera Felipe ''Físico'' s/n, 35017, Las Palmas de Gran Canaria, Spain; Department of Exercise Physiology, Faculty of Sports Sciences, University of Mazandaran, Babolsar, Mazandaran, Iran
Miriam Gelabert-Rebato
Department of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, 35017, Spain; Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Paseo Blas Cabrera Felipe ''Físico'' s/n, 35017, Las Palmas de Gran Canaria, Spain
Mario Perez-Valera
Department of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, 35017, Spain; Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Paseo Blas Cabrera Felipe ''Físico'' s/n, 35017, Las Palmas de Gran Canaria, Spain
Eduardo García-Gonzalez
Department of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, 35017, Spain; Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Paseo Blas Cabrera Felipe ''Físico'' s/n, 35017, Las Palmas de Gran Canaria, Spain
Alfredo Santana
Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Paseo Blas Cabrera Felipe ''Físico'' s/n, 35017, Las Palmas de Gran Canaria, Spain; Complejo Hospitalario Universitario Insular-Materno Infantil de Las Palmas de Gran Canaria, Clinical Genetics Unit, 35016, Las Palmas de Gran Canaria, Spain
Hans-Christer Holmberg
Department of Health Sciences, Luleå University of Technology, Sweden; School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, BC, Canada
Robert Boushel
School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, BC, Canada
Jostein Hallén
Department of Physical Performance, The Norwegian School of Sport Sciences, Postboks, 4014 Ulleval Stadion, 0806, Oslo, Norway
Jose A.L. Calbet
Department of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, 35017, Spain; Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Paseo Blas Cabrera Felipe ''Físico'' s/n, 35017, Las Palmas de Gran Canaria, Spain; School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, BC, Canada; Department of Physical Performance, The Norwegian School of Sport Sciences, Postboks, 4014 Ulleval Stadion, 0806, Oslo, Norway; Corresponding author. Departamento de Educación Física, Campus Universitario de Tafira, 35017, Las Palmas de Gran Canaria, Canary Islands, Spain.
When high-intensity exercise is performed until exhaustion a “functional reserve” (FR) or capacity to produce power at the same level or higher than reached at exhaustion exists at task failure, which could be related to reactive oxygen and nitrogen species (RONS)-sensing and counteracting mechanisms. Nonetheless, the magnitude of this FR remains unknown. Repeated bouts of supramaximal exercise at 120% of VO2max interspaced with 20s recovery periods with full ischaemia were used to determine the maximal FR. Then, we determined which muscle phenotypic features could account for the variability in functional reserve in humans. Exercise performance, cardiorespiratory variables, oxygen deficit, and brain and muscle oxygenation (near-infrared spectroscopy) were measured, and resting muscle biopsies were obtained from 43 young healthy adults (30 males). Males and females had similar aerobic (VO2max per kg of lower extremities lean mass (LLM): 166.7 ± 17.1 and 166.1 ± 15.6 ml kg LLM−1.min−1, P = 0.84) and anaerobic fitness (similar performance in the Wingate test and maximal accumulated oxygen deficit when normalized to LLM). The maximal FR was similar in males and females when normalized to LLM (1.84 ± 0.50 and 2.05 ± 0.59 kJ kg LLM−1, in males and females, respectively, P = 0.218). This FR depends on an obligatory component relying on a reserve in glycolytic capacity and a putative component generated by oxidative phosphorylation. The aerobic component depends on brain oxygenation and phenotypic features of the skeletal muscles implicated in calcium handling (SERCA1 and 2 protein expression), oxygen transport and diffusion (myoglobin) and redox regulation (Keap1). The glycolytic component can be predicted by the protein expression levels of pSer40-Nrf2, the maximal accumulated oxygen deficit and the protein expression levels of SOD1. Thus, an increased capacity to modulate the expression of antioxidant proteins involved in RONS handling and calcium homeostasis may be critical for performance during high-intensity exercise in humans.
