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Conducting Maximal and Submaximal Endurance Exercise Testing to Measure Physiological and Biological Responses to Acute Exercise in Humans
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Intercostal muscle blood flow is elevated in old rats during submaximal exercise
Joshua R Smith1, K Sue Hageman2, Craig A Harms3
1Department of Kinesiology, Kansas State University, Manhattan, KS, 66506, United States; Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, 55901, United States.
Respiratory Physiology & Neurobiology
|March 3, 2019
Summary
Older rats exhibit increased intercostal muscle blood flow (BF) and vascular conductance (VC) during exercise compared to younger rats. This suggests age-related changes in respiratory muscle oxygen delivery during physical exertion.
Area of Science:
- Physiology
- Aging Research
- Cardiovascular Physiology
Background:
- Exercise increases respiratory muscle blood flow (BF) in young adults.
- Aging can alter pulmonary function and respiratory muscle performance.
- Investigating age-related changes in respiratory muscle BF is crucial for understanding exercise limitations.
Purpose of the Study:
- To test the hypothesis that old rats have greater intercostal muscle BF and vascular conductance (VC) than young rats during submaximal exercise.
- To compare respiratory muscle hemodynamics between young and old rats during exercise.
Main Methods:
- Mean arterial pressure and respiratory muscle BFs were measured in young and old Fischer 344 X Brown Norway rats.
- Radiolabeled microspheres were used to determine blood flow to respiratory muscles.
- Measurements were taken at rest and during submaximal exercise.
Main Results:
- At rest, no significant differences in diaphragm, intercostal, or transversus abdominis BFs and VCs were observed between young and old rats.
- During submaximal exercise, old rats showed significantly higher intercostal BF and VC compared to young rats.
- Diaphragm and transversus abdominis BFs and VCs did not differ between age groups during exercise.
Conclusions:
- Intercostal muscle blood flow and vascular conductance are elevated in old rats relative to young rats during submaximal exercise.
- These findings highlight age-specific adaptations in respiratory muscle circulation during physical activity.
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