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Improvements in exercise performance with high-intensity interval training coincide with an increase in skeletal muscle mitochondrial content and function.
J Appl Physiol (1985) 2013; 115(6):785-93JA

Abstract

Six sessions of high-intensity interval training (HIT) are sufficient to improve exercise capacity. The mechanisms explaining such improvements are unclear. Accordingly, the aim of this study was to perform a comprehensive evaluation of physiologically relevant adaptations occurring after six sessions of HIT to determine the mechanisms explaining improvements in exercise performance. Sixteen untrained (43 ± 6 ml·kg(-1)·min(-1)) subjects completed six sessions of repeated (8-12) 60 s intervals of high-intensity cycling (100% peak power output elicited during incremental maximal exercise test) intermixed with 75 s of recovery cycling at a low intensity (30 W) over a 2-wk period. Potential training-induced alterations in skeletal muscle respiratory capacity, mitochondrial content, skeletal muscle oxygenation, cardiac capacity, blood volumes, and peripheral fatigue resistance were all assessed prior to and again following training. Maximal measures of oxygen uptake (Vo2peak; ∼8%; P = 0.026) and cycling time to complete a set amount of work (∼5%; P = 0.008) improved. Skeletal muscle respiratory capacities increased, most likely as a result of an expansion of skeletal muscle mitochondria (∼20%, P = 0.026), as assessed by cytochrome c oxidase activity. Skeletal muscle deoxygenation also increased while maximal cardiac output, total hemoglobin, plasma volume, total blood volume, and relative measures of peripheral fatigue resistance were all unaltered with training. These results suggest that increases in mitochondrial content following six HIT sessions may facilitate improvements in respiratory capacity and oxygen extraction, and ultimately are responsible for the improvements in maximal whole body exercise capacity and endurance performance in previously untrained individuals.

Authors+Show Affiliations

Zurich Center for Integrative Human Physiology (ZIHP Zurich, Switzerland;No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Evaluation Studies
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

23788574

Citation

Jacobs, Robert Acton, et al. "Improvements in Exercise Performance With High-intensity Interval Training Coincide With an Increase in Skeletal Muscle Mitochondrial Content and Function." Journal of Applied Physiology (Bethesda, Md. : 1985), vol. 115, no. 6, 2013, pp. 785-93.
Jacobs RA, Flück D, Bonne TC, et al. Improvements in exercise performance with high-intensity interval training coincide with an increase in skeletal muscle mitochondrial content and function. J Appl Physiol. 2013;115(6):785-93.
Jacobs, R. A., Flück, D., Bonne, T. C., Bürgi, S., Christensen, P. M., Toigo, M., & Lundby, C. (2013). Improvements in exercise performance with high-intensity interval training coincide with an increase in skeletal muscle mitochondrial content and function. Journal of Applied Physiology (Bethesda, Md. : 1985), 115(6), pp. 785-93. doi:10.1152/japplphysiol.00445.2013.
Jacobs RA, et al. Improvements in Exercise Performance With High-intensity Interval Training Coincide With an Increase in Skeletal Muscle Mitochondrial Content and Function. J Appl Physiol. 2013;115(6):785-93. PubMed PMID: 23788574.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Improvements in exercise performance with high-intensity interval training coincide with an increase in skeletal muscle mitochondrial content and function. AU - Jacobs,Robert Acton, AU - Flück,Daniela, AU - Bonne,Thomas Christian, AU - Bürgi,Simon, AU - Christensen,Peter Møller, AU - Toigo,Marco, AU - Lundby,Carsten, Y1 - 2013/06/20/ PY - 2013/6/22/entrez PY - 2013/6/22/pubmed PY - 2014/6/3/medline KW - HIT KW - interval training KW - mitochondria KW - oxygen extraction KW - sprint training SP - 785 EP - 93 JF - Journal of applied physiology (Bethesda, Md. : 1985) JO - J. Appl. Physiol. VL - 115 IS - 6 N2 - Six sessions of high-intensity interval training (HIT) are sufficient to improve exercise capacity. The mechanisms explaining such improvements are unclear. Accordingly, the aim of this study was to perform a comprehensive evaluation of physiologically relevant adaptations occurring after six sessions of HIT to determine the mechanisms explaining improvements in exercise performance. Sixteen untrained (43 ± 6 ml·kg(-1)·min(-1)) subjects completed six sessions of repeated (8-12) 60 s intervals of high-intensity cycling (100% peak power output elicited during incremental maximal exercise test) intermixed with 75 s of recovery cycling at a low intensity (30 W) over a 2-wk period. Potential training-induced alterations in skeletal muscle respiratory capacity, mitochondrial content, skeletal muscle oxygenation, cardiac capacity, blood volumes, and peripheral fatigue resistance were all assessed prior to and again following training. Maximal measures of oxygen uptake (Vo2peak; ∼8%; P = 0.026) and cycling time to complete a set amount of work (∼5%; P = 0.008) improved. Skeletal muscle respiratory capacities increased, most likely as a result of an expansion of skeletal muscle mitochondria (∼20%, P = 0.026), as assessed by cytochrome c oxidase activity. Skeletal muscle deoxygenation also increased while maximal cardiac output, total hemoglobin, plasma volume, total blood volume, and relative measures of peripheral fatigue resistance were all unaltered with training. These results suggest that increases in mitochondrial content following six HIT sessions may facilitate improvements in respiratory capacity and oxygen extraction, and ultimately are responsible for the improvements in maximal whole body exercise capacity and endurance performance in previously untrained individuals. SN - 1522-1601 UR - https://www.unboundmedicine.com/medline/citation/23788574/Improvements_in_exercise_performance_with_high_intensity_interval_training_coincide_with_an_increase_in_skeletal_muscle_mitochondrial_content_and_function_ L2 - http://www.physiology.org/doi/full/10.1152/japplphysiol.00445.2013?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -