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Intercostal muscle oxygenation and expiratory loaded breathing at rest: Respiratory pattern effect. Respir Physiol Neurobiol 2022; 304:103925. [PMID: 35662640 DOI: 10.1016/j.resp.2022.103925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 05/24/2022] [Accepted: 05/29/2022] [Indexed: 11/21/2022]
Abstract
In patients with airway obstruction, an increase in breathing frequency at rest is commonly associated with a dynamic hyperinflation (DH). In such a situation, intercostal muscle oxygenation may be disturbed. This hypothesis was examined in a context of simulated airway obstruction in healthy subjects. After a control period of 5 min, twelve participants (20 ± 2 years) breathed at rest through a 20-cmH2O expiratory threshold load, either by increasing or reducing their respiratory rate (ETLF+ or ETLF). Tissue saturation index (TSI) and concentration changes in oxyhaemoglobin (oxy[Hb+Mb]) were measured as well as cardiorespiratory variables. Inspiratory capacity was decreased in ETLF+ (p < 0.001) and correlated with dyspnea. An increase in oxy[Hb+Mb] occurred in ETLF+ that was higher than in ETLF (p < 0.01). TSI was not different between conditions. In healthy subjects at rest, an increase in respiratory rate during a simulated obstruction with an expiratory threshold load resulted in paradoxical response with DH emergence while intercostal muscle oxygenation was preserved.
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Differential Cortical Control of Chest Wall Muscles During Pressure- and Volume-Related Expiratory Tasks and the Effects of Acute Expiratory Threshold Loading. Motor Control 2019; 23:13-33. [PMID: 29902955 DOI: 10.1123/mc.2016-0055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 01/25/2018] [Accepted: 02/23/2018] [Indexed: 11/18/2022]
Abstract
We examined whether or not coherence between chest wall intercostal and oblique muscles changed as a function of lung volume excursion, alveolar pressure, and muscular demand. We also assessed the effects of acute expiratory threshold loading (ETL) on chest wall muscular control. A total of 15 healthy adults (7 males; average age = 28 years) completed maximum performance and ETL tasks. Chest wall surface electromyographic and kinematic recordings were made. Participants also performed a session of acute ETL. We showed that corticomuscular control of the chest wall varied as a function of lung volume excursion and muscular effort. Acute ETL had some effect on respiratory kinematics but not coherence.
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Kim CY, Lee JS, Kim HD, Lee DJ. Short-term effects of respiratory muscle training combined with the abdominal drawing-in maneuver on the decreased pulmonary function of individuals with chronic spinal cord injury: A pilot randomized controlled trial. J Spinal Cord Med 2017; 40:17-25. [PMID: 27463071 PMCID: PMC5376135 DOI: 10.1080/10790268.2016.1198576] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
OBJECTIVE To investigate the effects of respiratory muscle training (RMT) combined with the abdominal drawing-in maneuver (ADIM) on the pulmonary function in patients with chronic spinal cord injury (SCI). METHODS Thirty-seven subjects with SCI (level of injury: C4-T6, time since injury: 4-5 years) were randomly allocated to three groups; the integrated training group (ITG), the RMT group (RMTG), and the control group (CG). The ITG performed RMT using an incentive respiratory spirometer (IRS) and the ADIM using a stabilizer. The RMTG received only RMT using an IRS. Subjects in the CG received alternative and routine physical therapy or usual care. The interventions were conducted over an eight-week period. Pulmonary function was evaluated using spirometry to measure the forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1). RESULTS The differences between the pre- and post-test values for FVC (0.47 ± 0.05 versus 0.15 ± 0.06 versus -0.03 ± 0.01) and FEV1 (0.74 ± 0.07 versus 0.27 ± 0.17 versus 0.02 ± 0.67)were significant among the groups. Post-test, in the ITG, the FVC and FEV1 values showed significant differences from those in the RMTG and CG (F = 11.48 and 11.49, P = 0.002 and 0.001). Furthermore, following the 8-week intervention, the change ratio values of the FVC and FEV1 of the ITG were increased further by an average of 9.75% and 7.91%, respectively, compared with those of the RMTG. CONCLUSION These findings suggest positive evidence that RMT with additional ADIM training can improve pulmonary function in SCI pulmonary rehabilitation.
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Affiliation(s)
- Chang-Yong Kim
- Department of Health Science, The Graduate School, Korea University, Seoul, Republic of Korea
| | - Jung-Sun Lee
- Department of Epidemiology and Health Informatics, The Graduate School of Public Health, Korea University, Seoul, Republic of Korea
| | - Hyeong-Dong Kim
- Department of Physical Therapy, College of Health Science, Korea University, Seoul, Republic of Korea,Correspondence to: Hyeong-Dong Kim, Department of Physical Therapy, College of Health Science, Hana Science Building B ,Korea University, Anam-ro, Seongbuk-Gu, Seoul, 136-701, Republic of Korea.
| | - Dong-Jin Lee
- Department of Physical Therapy, Gwangju Health University, Gwangju, Republic of Korea
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Soilemezi E, Koco E, Tsimpos C, Tsagourias M, Savvidou S, Matamis D. Effects of continuous positive airway pressure on diaphragmatic kinetics and breathing pattern in healthy individuals. Respirology 2016; 21:1262-9. [DOI: 10.1111/resp.12823] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 03/15/2016] [Accepted: 03/18/2016] [Indexed: 01/16/2023]
Affiliation(s)
| | - Entela Koco
- Papageorgiou General Hospital; Thessaloniki Greece
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Yamashina Y, Yokoyama H, Naghavi N, Hirasawa Y, Takeda R, Ota A, Imai D, Miyagawa T, Okazaki K. Treadmill walking in water induces greater respiratory muscle fatigue than treadmill walking on land in healthy young men. J Physiol Sci 2016; 66:257-64. [PMID: 26582640 PMCID: PMC10717649 DOI: 10.1007/s12576-015-0423-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 10/26/2015] [Indexed: 10/22/2022]
Abstract
The purpose of the present study was to investigate the effect of walking in water on respiratory muscle fatigue compared with that of walking on land at the same exercise intensity. Ten healthy males participated in 40-min treadmill walking trials on land and in water at an intensity of 60% of peak oxygen consumption. Respiratory function and respiratory muscle strength were evaluated before and after walking trials. Inspiratory muscle strength and forced expiratory volume in 1 s were significantly decreased immediately after walking in water, and expiratory muscle strength was significantly decreased immediately and 5 min after walking in water compared with the baseline. The decreases of inspiratory and expiratory muscle strength were significantly greater compared with that after walking on land. In conclusion, greater inspiratory and expiratory muscle fatigue was induced by walking in water than by walking on land at the same exercise intensity in healthy young men.
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Affiliation(s)
- Yoshihiro Yamashina
- Department of Environmental Physiology for Exercise, Graduate School of Medicine, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka, Osaka, 558-8585, Japan
| | - Hisayo Yokoyama
- Department of Environmental Physiology for Exercise, Graduate School of Medicine, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka, Osaka, 558-8585, Japan.
- Research Center for Urban Health and Sports, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka, Osaka, 558-8585, Japan.
| | - Nooshin Naghavi
- Department of Environmental Physiology for Exercise, Graduate School of Medicine, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka, Osaka, 558-8585, Japan
| | - Yoshikazu Hirasawa
- Department of Environmental Physiology for Exercise, Graduate School of Medicine, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka, Osaka, 558-8585, Japan
| | - Ryosuke Takeda
- Department of Environmental Physiology for Exercise, Graduate School of Medicine, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka, Osaka, 558-8585, Japan
| | - Akemi Ota
- Department of Environmental Physiology for Exercise, Graduate School of Medicine, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka, Osaka, 558-8585, Japan
| | - Daiki Imai
- Department of Environmental Physiology for Exercise, Graduate School of Medicine, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka, Osaka, 558-8585, Japan
- Research Center for Urban Health and Sports, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka, Osaka, 558-8585, Japan
| | - Toshiaki Miyagawa
- Department of Environmental Physiology for Exercise, Graduate School of Medicine, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka, Osaka, 558-8585, Japan
- Research Center for Urban Health and Sports, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka, Osaka, 558-8585, Japan
| | - Kazunobu Okazaki
- Department of Environmental Physiology for Exercise, Graduate School of Medicine, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka, Osaka, 558-8585, Japan
- Research Center for Urban Health and Sports, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka, Osaka, 558-8585, Japan
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Yamashina Y, Yokoyama H, Naghavi N, Hirasawa Y, Takeda R, Ota A, Imai D, Miyagawa T, Okazaki K. Forced respiration during the deeper water immersion causes the greater inspiratory muscle fatigue in healthy young men. J Phys Ther Sci 2016; 28:412-8. [PMID: 27064401 PMCID: PMC4792982 DOI: 10.1589/jpts.28.412] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 10/30/2015] [Indexed: 11/24/2022] Open
Abstract
[Purpose] The purpose of the present study was to evaluate the effect of water immersion
at different water depths on respiratory function and the effect of inspiratory load
breathing (ILB) during water immersion at different water depths on respiratory muscle
strength evaluated by maximum inspiratory and expiratory pressures (PImax and PEmax,
respectively). [Subjects] Eight healthy men participated randomly in three trials.
[Methods] All sessions were conducted with the participants in a sitting position immersed
in a water bath. We evaluated respiratory function, PImax and PEmax during submersion at
three different levels of water depth (umbilicus; 4th-rib; or clavicle, CL) and after
subsequent 15-min ILB. [Results] Decreases in vital capacity and expiratory reserve volume
from baseline by water immersion were significantly greater in the CL trial than those in
the other trials. In the CL trial, PImax was immediately reduced after ILB compared to
that at baseline, and the reduction was significantly greater than those in the other
trials. PEmax was not affected by ILB in any of the trials. [Conclusion] Forced
respiration during deeper water immersion caused greater inspiratory muscle fatigue in
healthy young men.
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Affiliation(s)
- Yoshihiro Yamashina
- Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, Japan
| | - Hisayo Yokoyama
- Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, Japan
| | - Nooshin Naghavi
- Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, Japan
| | - Yoshikazu Hirasawa
- Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, Japan
| | - Ryosuke Takeda
- Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, Japan
| | - Akemi Ota
- Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, Japan
| | - Daiki Imai
- Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, Japan
| | - Toshiaki Miyagawa
- Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, Japan
| | - Kazunobu Okazaki
- Environmental Physiology for Exercise, Osaka City University Graduate School of Medicine, Japan
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Katayama K, Itoh Y, Saito M, Koike T, Ishida K. Sympathetic vasomotor outflow and blood pressure increase during exercise with expiratory resistance. Physiol Rep 2015; 3:3/5/e12421. [PMID: 26019293 PMCID: PMC4463841 DOI: 10.14814/phy2.12421] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The purpose of the present study was to elucidate the effect of increasing expiratory muscle work on sympathetic vasoconstrictor outflow and arterial blood pressure (BP) during dynamic exercise. We hypothesized that expiratory muscle fatigue would elicit increases in sympathetic vasomotor outflow and BP during submaximal exercise. The subjects performed four submaximal exercise tests; two were maximal expiratory pressure (PEmax) tests and two were muscle sympathetic nerve activity (MSNA) tests. In each test, the subjects performed two 10-min exercises at 40% peak oxygen uptake using a cycle ergometer in a semirecumbent position [spontaneous breathing for 5 min and voluntary hyperpnoea with and without expiratory resistive breathing for 5 min (breathing frequency: 60 breaths/min, inspiratory and expiratory times were set at 0.5 sec)]. PEmax was estimated before and immediately after exercises. MSNA was recorded via microneurography of the right median nerve at the elbow. PEmax decreased following exercise with expiratory resistive breathing, while no change was found without resistance. A progressive increase in MSNA burst frequency (BF) appeared during exercise with expiratory resistance (MSNA BF, without resistance: +22 ± 5%, with resistance: +44 ± 8%, P < 0.05), accompanied by an augmentation of BP (mean BP, without resistance: +5 ± 2%, with resistance: +29 ± 5%, P < 0.05). These results suggest that an enhancement of expiratory muscle activity leads to increases in sympathetic vasomotor outflow and BP during dynamic leg exercise.
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Affiliation(s)
- Keisho Katayama
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Yuka Itoh
- Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Mitsuru Saito
- Faculty of Psychological and Physical Science, Aichigakuin University, Nisshin, Japan
| | - Teruhiko Koike
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Koji Ishida
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan Graduate School of Medicine, Nagoya University, Nagoya, Japan
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8
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Kim CY, Lee JS, Kim HD, Kim IS. Effects of the combination of respiratory muscle training and abdominal drawing-in maneuver on respiratory muscle activity in patients with post-stroke hemiplegia: a pilot randomized controlled trial. Top Stroke Rehabil 2015; 22:262-70. [DOI: 10.1179/1074935714z.0000000020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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9
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Sugiura H, Sako S, Oshida Y. Effect of Expiratory Muscle Fatigue on the Respiratory Response during Exercise. J Phys Ther Sci 2013; 25:1491-5. [PMID: 24396218 PMCID: PMC3881485 DOI: 10.1589/jpts.25.1491] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 06/24/2013] [Indexed: 11/24/2022] Open
Abstract
[Purpose] The aim of this study was to reveal the effect of expiratory muscle fatigue
(EMF) on respiratory response under two different exercise conditions: exercise (EX) with
EMF (EMF-EX) and control EX without EMF (CON-EX). [Methods] Nine healthy adult men
performed cycle exercise with a ramp load, and a spirometer was used to measure forced
vital capacity (FVC), forced expiratory volume in one second, percent of forced expiratory
volume, maximal expiratory mouth pressure, and maximal inspiratory mouth pressure
(PImax) to evaluate respiratory functions immediately and at 15 and 30 min
after exercise. To assess the respiratory response during exercise, an exhaled gas
analyzer was used to measure minute ventilation (VE), respiratory frequency
(f), tidal volume (VT), oxygen uptake, and carbon dioxide output. In addition,
the Borg Scale was used to evaluate dyspnea, while electrocardiography was used to measure
heart rate. [Results] The results showed that compared with the CON-EX condition, no
change in VE, an increase in f, or a decrease in VT was observed
under the medium-intensity EMF-EX condition, while high-intensity exercise reduced
VE and f without changing VT. [Conclusion] These results suggest
that during medium-intensity exercise, EMF modulates the respiratory response by inducing
shallow and fast breathing to increase ventilation volume.
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Affiliation(s)
- Hiromichi Sugiura
- Department of Physical Therapy, Nagoya Isen, Japan ; Graduate School of Medicine, Nagoya University, Japan
| | - Shunji Sako
- Department of Physical Therapy, Nagoya Isen, Japan
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10
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Abstract
During dynamic exercise, the healthy pulmonary system faces several major challenges, including decreases in mixed venous oxygen content and increases in mixed venous carbon dioxide. As such, the ventilatory demand is increased, while the rising cardiac output means that blood will have considerably less time in the pulmonary capillaries to accomplish gas exchange. Blood gas homeostasis must be accomplished by precise regulation of alveolar ventilation via medullary neural networks and sensory reflex mechanisms. It is equally important that cardiovascular and pulmonary system responses to exercise be precisely matched to the increase in metabolic requirements, and that the substantial gas transport needs of both respiratory and locomotor muscles be considered. Our article addresses each of these topics with emphasis on the healthy, young adult exercising in normoxia. We review recent evidence concerning how exercise hyperpnea influences sympathetic vasoconstrictor outflow and the effect this might have on the ability to perform muscular work. We also review sex-based differences in lung mechanics.
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Affiliation(s)
- Andrew William Sheel
- The School of Kinesiology, The University of British Columbia, Vancouver, Canada.
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11
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Reilly CC, Ward K, Jolley CJ, Frank LA, Elston C, Moxham J, Rafferty GF. Effect of endurance exercise on respiratory muscle function in patients with cystic fibrosis. Respir Physiol Neurobiol 2012; 180:316-22. [DOI: 10.1016/j.resp.2011.12.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 12/15/2011] [Accepted: 12/20/2011] [Indexed: 11/17/2022]
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12
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Effect of expiratory resistive loading on inspiratory and expiratory muscle fatigue. Respir Physiol Neurobiol 2009; 166:164-74. [DOI: 10.1016/j.resp.2009.03.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 03/02/2009] [Accepted: 03/05/2009] [Indexed: 11/20/2022]
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13
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Taylor BJ, Romer LM. Effect of expiratory muscle fatigue on exercise tolerance and locomotor muscle fatigue in healthy humans. J Appl Physiol (1985) 2008; 104:1442-51. [DOI: 10.1152/japplphysiol.00428.2007] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
High-intensity exercise (≥90% of maximal O2 uptake) sustained to the limit of tolerance elicits expiratory muscle fatigue (EMF). We asked whether prior EMF affects subsequent exercise tolerance. Eight male subjects (means ± SD; maximal O2 uptake = 53.5 ± 5.2 ml·kg−1·min−1) cycled at 90% of peak power output to the limit of tolerance with (EMF-EX) and without (CON-EX) prior induction of EMF and for a time equal to that achieved in EMF-EX but without prior induction of EMF (ISO-EX). To induce EMF, subjects breathed against an expiratory flow resistor until task failure (15 breaths/min, 0.7 expiratory duty cycle, 40% of maximal expiratory gastric pressure). Fatigue of abdominal and quadriceps muscles was assessed by measuring the reduction relative to prior baseline values in magnetically evoked gastric twitch pressure (Pgatw) and quadriceps twitch force (Qtw), respectively. The reduction in Pgatw was not different after resistive breathing vs. after CON-EX (−27 ± 5 vs. −26 ± 6%; P = 0.127). Exercise time was reduced by 33 ± 10% in EMF-EX vs. CON-EX (6.85 ± 2.88 vs. 9.90 ± 2.94 min; P < 0.001). Exercise-induced abdominal and quadriceps muscle fatigue was greater after EMF-EX than after ISO-EX (−28 ± 9 vs. −12 ± 5% for Pgatw, P = 0.001; −28 ± 7 vs. −14 ± 6% for Qtw, P = 0.015). Perceptual ratings of dyspnea and leg discomfort (Borg CR10) were higher at 1 and 3 min and at end exercise during EMF-EX vs. during ISO-EX ( P < 0.05). Percent changes in limb fatigue and leg discomfort (EMF-EX vs. ISO-EX) correlated significantly with the change in exercise time. We propose that EMF impaired subsequent exercise tolerance primarily through an increased severity of limb locomotor muscle fatigue and a heightened perception of leg discomfort.
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Verges S, Sager Y, Erni C, Spengler CM. Expiratory muscle fatigue impairs exercise performance. Eur J Appl Physiol 2007; 101:225-32. [PMID: 17546459 DOI: 10.1007/s00421-007-0491-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2007] [Indexed: 11/24/2022]
Abstract
High-intensity, exhaustive exercise may lead to inspiratory as well as expiratory muscle fatigue (EMF). Induction of inspiratory muscle fatigue (IMF) before exercise has been shown to impair subsequent exercise performance. The purpose of the present study was to determine whether induction of EMF also affects subsequent exercise performance. Twelve healthy young men performed five 12-min running tests on a 400-m track on separate days: a preliminary trial, two trials after induction of EMF, and two trials without prior muscle fatigue. Tests with and without prior EMF were performed in an alternate order, randomly starting with either type. EMF was defined as a >or=20% drop in maximal expiratory mouth pressure achieved during expiratory resistive breathing against 50% maximal expiratory mouth pressure. The average distance covered in 12 min was significantly smaller during exercise with prior EMF compared to control exercise (2872+/-256 vs. 2957+/-325 m; P=0.002). Running speed was consistently lower (0.13 m s(-1)) throughout the entire 12 min of exercise with prior EMF. A significant correlation was observed between the level of EMF (decrement in maximal expiratory mouth pressure after resistive breathing) and the reduction in running distance (r2=0.528, P=0.007). Perceived respiratory exertion was higher during the first 800 m and heart rate was lower throughout the entire test of running with prior EMF compared to control exercise (5.3+/-1.6 vs. 4.5+/-1.7 points, P=0.002; 173+/-10 vs. 178+/-7 beats min(-1), P=0.005). We conclude that EMF impairs exercise performance as previously reported for IMF.
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Affiliation(s)
- S Verges
- Institute of Physiology and Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
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Taylor BJ, How SC, Romer LM. Exercise-induced abdominal muscle fatigue in healthy humans. J Appl Physiol (1985) 2006; 100:1554-62. [PMID: 16424068 DOI: 10.1152/japplphysiol.01389.2005] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The abdominal muscles have been shown to fatigue in response to voluntary isocapnic hyperpnea using direct nerve stimulation techniques. We investigated whether the abdominal muscles fatigue in response to dynamic lower limb exercise using such techniques. Eleven male subjects [peak oxygen uptake (VO2 peak) = 50.0 +/- 1.9 (SE) ml.kg(-1).min(-1)] cycled at >90% VO2 peak to exhaustion (14.2 +/- 4.2 min). Abdominal muscle function was assessed before and up to 30 min after exercise by measuring the changes in gastric pressure (Pga) after the nerve roots supplying the abdominal muscles were magnetically stimulated at 1-25 Hz. Immediately after exercise there was a decrease in Pga at all stimulation frequencies (mean -25 +/- 4%; P < 0.001) that persisted up to 30 min postexercise (-12 +/- 4%; P = 0.001). These reductions were unlikely due to changes in membrane excitability because amplitude, duration, and area of the rectus abdominis M wave were unaffected. Declines in the Pga response to maximal voluntary expiratory efforts occurred after exercise (158 +/- 13 before vs. 145 +/- 10 cmH2O after exercise; P = 0.005). Voluntary activation, assessed using twitch interpolation, did not change (67 +/- 6 before vs. 64 +/- 2% after exercise; P = 0.20), and electromyographic activity of the rectus abdominis and external oblique increased during these volitional maneuvers. These data provide new evidence that the abdominal muscles fatigue after sustained, high-intensity exercise and that the fatigue is primarily due to peripheral mechanisms.
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Affiliation(s)
- Bryan J Taylor
- Centre for Sports Medicine and Human Performance, School of Sport and Education, Brunel University, Middlesex, UB8 3PH UK
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Verges S, Schulz C, Perret C, Spengler CM. Impaired abdominal muscle contractility after high-intensity exhaustive exercise assessed by magnetic stimulation. Muscle Nerve 2006; 34:423-30. [PMID: 16810695 DOI: 10.1002/mus.20599] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
High-intensity exercise can induce diaphragm fatigue which can, in turn, limit exercise performance. We investigated whether expiratory muscles fatigue similarly during exhaustive exercise. Eleven healthy male volunteers cycled to exhaustion at 85% maximal power. Before, immediately after exercise, and after 30 and 60 min of recovery, the nerve roots supplying the abdominal muscles were stimulated magnetically at the T10 level in the prone position after full potentiation. Twitch gastric pressure (Pga,tw) was simultaneously recorded. After cycling, Pga,tw was significantly reduced compared to before exercise (40.2 +/- 6.6 vs. 45.3 +/- 7.5 cmH2O; P < 0.001), whereas after 30 and 60 min of recovery differences were no longer significant. The reduction in Pga,tw directly after exercise correlated neither with the fitness level nor with abdominal muscle work, respiratory sensations, or blood lactate concentration during exercise. These results indicate that the ventilatory requirements during intensive exercise can impair abdominal muscle contractility similar to diaphragmatic contractility. Thus, abdominal muscle fatigue may also contribute to exercise limitation, especially when expiratory resistance is increased as in patients with chronic obstructive pulmonary disease.
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Affiliation(s)
- Samuel Verges
- Exercise Physiology, Institute for Human Movement Sciences, ETH Zurich, and Institute of Physiology and Center for Integrative Human Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
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Ratnovsky A, Zaretsky U, Shiner RJ, Elad D. Integrated approach for in vivo evaluation of respiratory muscles mechanics. J Biomech 2003; 36:1771-84. [PMID: 14614931 DOI: 10.1016/s0021-9290(03)00232-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The respiratory muscles constitute the respiratory pump, which determines the efficacy of ventilation. Any functional disorder in their performance may cause insufficient ventilation. This study was designed to quantitatively explore the relative contribution of major groups of respiratory muscles to global lung ventilation throughout a range of maneuvers in healthy subjects. A computerized experimental system was developed for simultaneous noninvasive measurement of inspired/expired airflow, mouth pressure and up to 8 channels of EMG surface signals from major respiratory muscles which are located near the skin (e.g., sternomastoid, external intercostal, rectus abdominis and external oblique) during various respiratory maneuvers. Lung volumes values were calculated by integration of airflow data. Hill's muscle model was utilized to calculate the forces generated by the muscles from the acquired EMG data. Analysis of EMG measurements and respiratory muscles forces revealed the following characteristics: (a) muscle activity increased with increased breathing effort, (b) inspiratory muscles contributed to inspiration even at relatively low flow rates, while expiratory muscles are recruited at higher flow rates, (c) the forces generated by the muscle depended on the muscle properties as well as on their EMG performance and (d) the pattern of the muscle's force curves varied between subjects, but were generally consistent for the same subject regardless of breathing effort.
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Affiliation(s)
- Anat Ratnovsky
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
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Derchak PA, Sheel AW, Morgan BJ, Dempsey JA. Effects of expiratory muscle work on muscle sympathetic nerve activity. J Appl Physiol (1985) 2002; 92:1539-52. [PMID: 11896021 DOI: 10.1152/japplphysiol.00790.2001] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We hypothesized that contractions of the expiratory muscles carried out to the point of task failure would cause an increase in muscle sympathetic nerve activity (MSNA). We measured MSNA directly in six healthy men during resisted expiration (60% maximal expiratory pressure) leading to task failure with long [breathing frequency (f(b)) = 15 breaths/min; expiratory time (TE)/total respiratory cycle duration (TT) = 0.7] and short (f(b) = 30 breaths/min; TE/TT = 0.4) TE. Both of these types of expiratory muscle contractions elicited time-dependent increases in MSNA burst frequency that averaged +139 and +239%, respectively, above baseline at end exercise. The increased MSNA coincided with increases in mean arterial pressure (MAP) for both the long-TE (+28 +/- 6 mmHg) and short-TE (+22 +/- 14 mmHg) trials. Neither MSNA nor MAP changed when the breathing patterns and increased tidal volume of the task failure trials were mimicked without resistance or task failure. Furthermore, very high levels of expiratory motor output (95% maximal expiratory pressure; f(b) = 12 breaths/min; TE/TT = 0.35) and high rates of expiratory flow and expiratory muscle shortening without task failure (no resistance; f(b) = 45 breaths/min; TE/TT = 0.4; tidal volume = 1.9 x eupnea) had no effect on MSNA or MAP. Within-breath analysis of the short-expiration trials showed augmented MSNA at the onset of and throughout expiration that was consistent with an influence of high levels of central expiratory motor output. Thus high-intensity contractions of expiratory muscles to the point of task failure caused a time-dependent sympathoexcitation; these effects on MSNA were similar in their time dependency to those caused by high-intensity rhythmic contractions of the diaphragm and forearm muscles taken to the point of task failure. The evidence suggests that these effects are mediated primarily via a muscle metaboreflex with a minor, variable contribution from augmented central expiratory motor output.
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Affiliation(s)
- P Alexander Derchak
- John Rankin Laboratory of Pulmonary Medicine, Department of Population Health Sciences, University of Wisconsin, Madison, Wisconsin 53705, USA
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Ramírez-Sarmiento A, Orozco-Levi M, Barreiro E, Méndez R, Ferrer A, Broquetas J, Gea J. Expiratory muscle endurance in chronic obstructive pulmonary disease. Thorax 2002; 57:132-6. [PMID: 11828042 PMCID: PMC1746253 DOI: 10.1136/thorax.57.2.132] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND A reduction in expiratory muscle (ExM) endurance in patients with chronic obstructive pulmonary disease (COPD) may have clinically relevant implications. This study was carried out to evaluate ExM endurance in patients with COPD. METHODS Twenty three patients with COPD (FEV(1) 35 (14)% predicted) and 14 matched controls were studied. ExM endurance was assessed using a method based on the use of an expiratory threshold valve which includes two steps. In step 1 the load is progressively increased (50 g every 2 minutes) until task failure is reached, and the pressure generated against the highest tolerated load is defined as the maximal expiratory sustainable pressure (Pthmax). In step 2 subjects breathe against a submaximal constant load (80% of Pthmax) and the time elapsed until task failure is termed the expiratory endurance time (Tth(80)). In addition, the strength of peripheral muscles (handgrip, HGS) and respiratory muscles (maximal inspiratory and expiratory pressures, PImax and PEmax, respectively) was evaluated. RESULTS Patients with COPD had lower ExM strength and endurance than controls: PEmax 64 (19)% predicted v 84 (14)% predicted (mean difference 20%; 95% confidence intervals (CI) 14 to 39); Pthmax 52 (27) v 151 (46) cm H(2)O (mean difference 99, 95% CI 74 to 123); and Tth(80) 9.4 (6.3) v 14.2 (7.4) min (mean difference 4.8, 95% CI 1.0 to 10.4; p<0.01 for all). Interestingly, ExM endurance directly correlated with both the severity of airways obstruction (Pthmax with FEV(1), r=0.794, p<0.01) and the reduction in strength observed in different muscle groups (Pthmax with HG, PImax or PEmax, r=0.550, p<0.05; r=0.583, p<0.001; and r=0.584, p<0.001, respectively). CONCLUSIONS ExM endurance is decreased in patients with COPD. This impairment is proportional to the severity of the disease and is associated with lower strength in different muscle groups. This suggests that systemic effects are implicated in the impairment observed in ExM function.
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Affiliation(s)
- A Ramírez-Sarmiento
- Servei de Pneumologia and Unitat de Recerca Respiratòria I Ambiental, Hospital del Mar-IMIM, Barcelona, Spain
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20
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Boussana A, Matecki S, Galy O, Hue O, Ramonatxo M, Le Gallais D. The effect of exercise modality on respiratory muscle performance in triathletes. Med Sci Sports Exerc 2001; 33:2036-43. [PMID: 11740296 DOI: 10.1097/00005768-200112000-00010] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The aim of this study was to examine the effects of the cycle-run and run-cycle successions of the triathlon and duathlon, respectively, on respiratory muscle strength and endurance. METHODS Respiratory muscle strength was assessed by measuring maximal inspiratory (P(Imax)) and expiratory (P(Emax)) pressures. Respiratory muscle endurance was assessed by measuring the time limit (T(lim)). Twelve triathletes participated in a three-trial protocol. The first trial consisted of an incremental cycle test to assess the maximal oxygen uptake (.VO(2max)) of triathletes. Trial 2 consisted of 20 min of cycling followed by 20 min of running (C-R), and trial 3 consisted of 20 min of running followed by 20 min of cycling (R-C). Trials 2 and 3 were performed at the same metabolic intensity (%.VO(2max)). P(Imax) and P(Emax) were measured before and 10 min after C-R and R-C, and 1 min after the post-C-R and post-R-C T(lim) measurements (P(Imax) 1'). T(lim) was measured 1 d before and 30 min after C-R and R-C. RESULTS The results showed a significant decrease in P(Imax) after C-R (126.7 +/- 4.3 cmH(2)O, P < 0.05) and R-C (123.7 +/- 4.9 cmH(2)O, P < 0.05) compared with the baseline values (130 +/- 3.8 and 129.6 +/- 4.3 cmH(2)O, respectively). P(Imax) 1' showed a significantly greater decrease after R-C versus C-R (111.2 +/- 5.5 cmH(2)O vs 121.2 +/- 3.9 cmH(2O), respectively, P < 0.001). Tlim after C-R (3.3 +/- 0.3 min) and R-C (2.1 +/- 0.3 min) decreased significantly compared with baseline values (4.19 +/- 0.3 min and 4.02 +/- 0.3 min, respectively). However, the Tlim decrease after R-C was significantly greater than after C-R (P < 0.001). CONCLUSION We concluded that respiratory muscle strength and endurance were less decreased after the cycle-run succession and that cycling induced a greater decrease in respiratory muscle endurance than running.
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Affiliation(s)
- A Boussana
- Laboratoire Sport Performance Santé, Faculté des Sciences du Sport, 700 Avenue du Pic Saint Loup, F-34090 Montpellier, France
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Rogers IR, Inglis S, Speedy D, Hillman D, Noffsinger B, Jacobs I. Changes in respiratory function during a wilderness multisport endurance competition. Wilderness Environ Med 2001; 12:13-6. [PMID: 11294549 DOI: 10.1580/1080-6032(2001)012[0013:cirfda]2.0.co;2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To document the changes in respiratory function seen in competitors during a typical wilderness multisport endurance event. METHODS A prospective observational cohort study measuring forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) at baseline, midrace, and end of race in competitors in a 105-km ski/run/cycle/paddle race held midwinter in the mountains of Victoria, Australia. RESULTS Twenty-five adult subjects (22 men) between 20 and 42 years of age were studied. The mean decline in FEV1 was 15.1% (95% CI 10.3-19.8) and for FVC was 13.0% (95% CI 8.1-17.9). Fourteen (56%) of the 25 subjects had a >10% decline in FEV1 and FVC, and 7 (28%) of the 25 subjects had a >20% decline. In 9 control subjects, aged between 21 and 55 years, there was no significant change in FEV1 or FVC from prerace to end of race. CONCLUSIONS Significant declines in FEV1 and FVC are common during wilderness multisport endurance events. The focus of future research should be the etiology, which as yet remains speculative.
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Affiliation(s)
- I R Rogers
- Department of Emergency Medicine, Sir Charles Gairdner Hospital, Perth, Australia
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Ferrer A, Orozco-Levi M, Gea J, Méndez R, Ramírez AL, Broquetas JM. [Mechanical and metabolic reproducibility of resistance test of expiratory muscles with incremental threshold loading]. Arch Bronconeumol 2000; 36:303-12. [PMID: 10932339 DOI: 10.1016/s0300-2896(15)30149-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The study of respiratory muscle endurance has mainly focused on inspiratory muscles. A new method to measure expiratory muscle endurance, through incremental threshold loading using a weighted plunger valve, has recently been described. OBJECTIVES To evaluate the mechanical features of the plunger valve and the reproducibility of the method from the standpoint of both mechanics and metabolism. METHODS Four untrained healthy subjects performed an incremental test with expiratory threshold loading (50 g every 2 min) on each of three non-consecutive days; each test continued until the subject could no longer open the valve. Mouth pressure was recorded continuously during each test; on the first two test days, oxygen consumption (VO2) was also measured. RESULTS Opening and closing pressures were the same and were independent of expiratory flow, with a linear load-pressure relationship (4 cmH2O) for every 10 g of weight). The maximal tolerated load (MTL) in the three tests was stable for two of the subjects, whereas the maximal load was reached by the other two subjects in the second and third tests, respectively. When MTL was reached in the third test, mean and peak mouth pressures (the latter expressed as percent of maximal expiratory pressure [MEP]) were 49 +/- 4% and 71 +/- 4%, respectively; the expiratory tension-time index measured at the mouth ([PMEANmouth/MEP] x [TE/Ttot]) was 0.25 +/- 0.02 (TE: expiratory time; Ttot: total time). In the first and second tests, we also measured oxygen consumption of the recruited muscles, which were mainly the expiratory muscles (VO2respmax); consumption in the last test was 213 +/- 65 ml O2/min (2.9 +/- 1.1 ml O2/kg/min). The intraindividual coefficient of variation ranged from 6.3% to 19.5% for the mechanical parameters and from 14% to 21% for the metabolic ones. CONCLUSIONS The expiratory endurance test using a threshold valve allows quantification of muscle and metabolic reserve under incremental expiratory loads. The valve has appropriate mechanical characteristics for this purpose and reproducibility is acceptable, through the precise determination of the may require up to three tests.
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Affiliation(s)
- A Ferrer
- Servei de Pneumologia, Hospital del Mar, Universitat Pompeu Fabra, Barcelona.
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Suzuki J, Tanaka R, Yan S, Chen R, Macklem PT, Kayser B. Assessment of abdominal muscle contractility, strength, and fatigue. Am J Respir Crit Care Med 1999; 159:1052-60. [PMID: 10194145 DOI: 10.1164/ajrccm.159.4.9803025] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We evaluated abdominal muscle contractility and fatigue by measuring twitch gastric pressure (Pgat) after percutaneous supramaximal electrical stimulation of the abdominal wall before and after sit-ups to task failure. Mouth pressures during maximal voluntary expulsive maneuvers (PEmax) at TLC and FRC with superimposed twitches, and maximum voluntary ventilation (MVV) were also assessed. Mean fresh Pgat was 36.1 +/- 3.0 cm H2O with a coefficient of variation that ranged between 3.0 to 4.8%. Pgat decreased by 25% (p < 0.001) and 37% (p < 0.001) at 1 and 30 min after sit-ups. During maximal voluntary contraction twitch occlusion never occurred. PEmax at TLC and FRC decreased by 15% (p < 0.001) and 11% (p < 0.017) at 1 min, and 8% (p < 0.036) and 9% (p < 0.030) at 30 min after sit-ups, respectively. Despite the abdominal muscle fatigue, MVV values at 1 and 30 min after sit-ups were not significantly different from the value obtained before the sit-ups. We conclude that (1) Pgat is a useful objective indicator of abdominal muscle contractility and fatigue; (2) during maximal voluntary expulsive maneuvers the abdominal muscles are never fully activated; (3) sit-ups lead to substantial low-frequency fatigue but little high-frequency fatigue of the abdominal muscles, which has little effect on maximal breathing capacity.
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Affiliation(s)
- J Suzuki
- Meakins-Christie Laboratories, Montreal Chest Institute, Royal Victoria Hospital, McGill University, Montreal, Quebec, Canada
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Suzuki S, Sato M, Okubo T. Expiratory muscle training and sensation of respiratory effort during exercise in normal subjects. Thorax 1995; 50:366-70. [PMID: 7785008 PMCID: PMC474277 DOI: 10.1136/thx.50.4.366] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND The sensation of respiratory effort may increase as expiratory muscles become fatigued during expiratory loading. A study was performed to determine whether expiratory muscle training (EMT) affects the sensation of respiratory effort during exercise in healthy subjects. METHODS Six subjects performed EMT for 15 minutes twice daily for four weeks using a pressure threshold device; another six subjects served as a control group. The expiratory threshold was set at 30% of the individual's maximum expiratory mouth pressure (PEmax). The sensation of respiratory effort was evaluated during a progressive exercise test using the Borg scale. RESULTS After EMT PEmax increased by 25% in the training group. The Borg score increased as exercise grade increased before and after EMT, but scores for each grade were lower after EMT. Minute ventilation during exercise decreased after EMT, as did the breathing frequency during exercise, while the expiratory time increased. Although there was no difference in the relationship between Borg score and minute ventilation before or after EMT, the curve shifted to a lower Borg score after EMT. There were no changes in PEmax, Borg score, minute ventilation, or breathing pattern after the four week study period in the control group. CONCLUSION These findings suggest that EMT increases expiratory muscle strength and reduces the sensation of respiratory effort during exercise, presumably by reducing minute ventilation.
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Affiliation(s)
- S Suzuki
- First Department of Internal Medicine, Yokohama City University School of Medicine, Kanagawa, Japan
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Goldstein RS. Pulmonary rehabilitation in chronic respiratory insufficiency. 3. Ventilatory muscle training. Thorax 1993; 48:1025-33. [PMID: 8256233 PMCID: PMC464822 DOI: 10.1136/thx.48.10.1025] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Suzuki S, Yoshiike Y, Suzuki M, Akahori T, Hasegawa A, Okubo T. Inspiratory muscle training and respiratory sensation during treadmill exercise. Chest 1993; 104:197-202. [PMID: 8325069 DOI: 10.1378/chest.104.1.197] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We studied whether inspiratory muscle training (IMT) changed respiratory sensation during exercise in 12 healthy women; IMT was performed twice daily, for 15 minutes, using a pressure threshold device and continued for 4 weeks. The inspiratory threshold was set to 30 percent of each individual's maximal inspiratory pressure (Pimax). Breathing effort was evaluated during a progressive exercise test using Borg scale. After IMT, both Pimax and maximal transdiaphragmatic pressure increased by 30 percent in the training group (p < 0.05) but did not change in the control group. Prior to IMT, the Borg score increased in proportion to exercise grade. The difference in the sensory score-exercise stage curves before and after IMT in the training group was not significant. No significant difference was noted in the relationship of the Borg score to minute ventilation before and after 4 weeks in either group. We concluded that IMT may not affect respiratory sensation during exercise in normal subjects, although IMT increases diaphragmatic strength.
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Affiliation(s)
- S Suzuki
- 1st Department of Internal Medicine, Yokohama City University School of Medicine, Kanagawa, Japan
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Powers SK, Grinton S, Lawler J, Criswell D, Dodd S. High intensity exercise training-induced metabolic alterations in respiratory muscles. RESPIRATION PHYSIOLOGY 1992; 89:169-77. [PMID: 1439299 DOI: 10.1016/0034-5687(92)90048-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Limited information exists concerning the effects of high intensity interval exercise training (HIET) on metabolic alterations in both inspiratory and expiratory muscles. To test the hypothesis that HIET will improve the oxidative capacity of the diaphragm and major expiratory muscles, we examined Krebs cycle and beta oxidation enzyme activities in the diaphragm and three groups of expiratory (abdominal) muscles in rats subjected to 12 weeks (5 days.wk-1) of treadmill exercise. Two groups of female Sprague-Dawley rats (age ca 120 days) were studied: (1) HIET group (n = 10; animals performed 6 x ca 5-min running intervals.day-1 at ca 90-95% VO2max); (2) sedentary control group (n = 7). When compared to controls, HIET resulted in significantly elevated (P less than 0.05) activities of 3-hydroxy-acyl-Co-A dehydrogenase (HADH) and citrate synthase (CS) in the costal diaphragm, rectus abdominus, external obliques, and the plantaris muscles. In contrast, training did not increase (P greater than 0.05) the activities of CS or HADH in the crural diaphragm or the internal obliques/transversus abdominus muscles. By comparison, the training-induced increases in oxidative capacity (e.g., CS activity) in the costal diaphragm, rectus abdominus, and external obliques were relatively small (ca 23, 10, 12%, respectively) when contrasted to the exercise-induced increase in CS activity in the plantaris muscle (ca 47%). We conclude that HIET results in small but significant improvements in the oxidative and beta oxidation capacities of the costal diaphragm and at least two abdominal expiratory muscles.
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Affiliation(s)
- S K Powers
- Department of Exercise and Sport Sciences, University of Florida, Gainesville 32611
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