Daussin 2008 Am J Physiol Regul Integr Comp Physiol

Daussin FN, Zoll J, Dufour SP, Ponsot E, Lonsdorfer-Wolf E, Doutreleau S, Mettauer B, Piquard F, Geny B, Richard R (2008) Effect of interval versus continuous training on cardiorespiratory and mitochondrial functions: relationship to aerobic performance improvements in sedentary subjects. Am J Physiol Regul Integr Comp Physiol 295:R264-72.

» PMID: 18417645 Open Access

Daussin FN, Zoll J, Dufour SP, Ponsot E, Lonsdorfer-Wolf E, Doutreleau S, Mettauer B, Piquard F, Geny B, Richard R (2008) Am J Physiol Regul Integr Comp Physiol

Abstract: The goal of the study was to determine the effects of continuous (CT) vs. intermittent (IT) training yielding identical mechanical work and training duration on skeletal muscle and cardiorespiratory adaptations in sedentary subjects. Eleven subjects (6 men and 5 women, 45 +/- 3 years) were randomly assigned to either of the two 8-wk training programs in a cross-over design, separated by 12 wk of detraining. Maximal oxygen uptake (Vo2max) increased after both trainings (9% with CT vs. 15% with IT), whereas only IT was associated with faster Vo2 kinetics (tau: 68.0 +/- 1.6 vs. 54.9 +/- 0.7 s, P < 0.05) measured during a test to exhaustion (TTE) and with improvements in maximal cardiac output (Qmax, from 18.1 +/- 1.1 to 20.1 +/- 1.2 l/min; P < 0.01). Skeletal muscle mitochondrial oxidative capacities (Vmax) were only increased after IT (3.3 +/- 0.4 before and 4.5 +/- 0.6 micromol O2 x min(-1) x g dw(-1) after training; P < 0.05), whereas capillary density increased after both trainings, with a two-fold higher enhancement after CT (+21 +/- 1% for IT and +40 +/- 3% after CT, P < 0.05). The gain of Vmax was correlated with the gain of TTE and the gain of Vo2max with IT. The gain of Qmax was also correlated with the gain of VO2max. These results suggest that fluctuations of workload and oxygen uptake during training sessions, rather than exercise duration or global energy expenditure, are key factors in improving muscle oxidative capacities. In an integrative view, IT seems optimal in maximizing both peripheral muscle and central cardiorespiratory adaptations, permitting significant functional improvement. These data support the symmorphosis concept in sedentary subjects.

• Bioblast editor: Gnaiger E

Labels: MiParea: Respiration, Exercise physiology;nutrition;life style 

Organism: Human  Tissue;cell: Skeletal muscle  Preparation: Intact organism, Permeabilized tissue 

Coupling state: OXPHOS  Pathway: N 

MitoEAGLE V_O2max/BME data base

• Human vastus lateralis
• 4 females & 7 males
• 45 years
• Sedentary; CT control
• h = 1.74 m
• m = 76 kg
• BME = 1.23
• BMI = 25.1 kg·m^-2
• V_O2max/BM = 31.6 mL·min^-1·kg^-1 (= V_O2peak/BM/0.93)
• Permeabilized muscle fibres; 22 °C; GM_P; m_d; conversions: Gnaiger 2009 Int J Biochem Cell Biol
• J_O2,P(NS) = 60.9 µmol·s^-1·kg^-1 wet muscle mass (37 °C)

• J_O2,P(GM) = 44.4 µmol·s^-1·kg^-1 wet muscle mass (37 °C)
• J_O2,P(NS) = J_O2,P(GM)/0.73
• Fiber wet mass to dry mass ratio = 3.5 (N'Guessan 2004 Mol Cell Biochem)

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