Effect of aerobic fitness on capillary blood volume and diffusing membrane capacity responses to exercise

Abstract

Key points Endurance trained athletes exhibit enhanced cardiovascular function compared to non‐athletes, although it is considered that exercise training does not enhance lung structure and function.An increased pulmonary capillary blood volume at rest is associated with a higher V˙O2 max .In the present study, we compared the diffusion capacity, pulmonary capillary blood volume and diffusing membrane capacity responses to exercise in endurance‐trained males compared to non‐trained males.Exercise diffusion capacity was greater in athletes, secondary to an increased membrane diffusing capacity, and not pulmonary capillary blood volume.Endurance‐trained athletes appear to have differences within the pulmonary membrane that facilitate the increased O2 demand needed for high‐level exercise. AbstractEndurance‐trained athletes exhibit enhanced cardiovascular function compared to non‐athletes, allthough it is generally accepted that exercise training does not enhance lung structure and function. Recent work has shown that an increased resting pulmonary capillary blood volume (V C) is associated with a higher maximum oxygen consumption (V˙O2 max ), although there have been no studies to date examining how aerobic fitness affects the V C response to exercise. Based on previous work, we hypothesized that endurance‐trained athletes will have greater V C compared to non‐athletes during cycling exercise. Fifteen endurance‐trained athletes (HI: V˙O2 max 64.6 ± 1.8 ml kg−1 min−1) and 14 non‐endurance trained males (LO: V˙O2 max 45.0 ± 1.2 ml kg−1 min−1) were matched for age and height. Haemoglobin‐corrected diffusion capacity (DLCO), V C and diffusing membrane capacity (D M) were determined using the Roughton and Forster (1957) multiple fraction of inspired O2 (FIO2)‐DLCO method at baseline and during incremental cycle exercise up to 90% of peak O2 consumption. During exercise, both groups exhibited increases in DLCO, D M and V C with exercise intensity. Athletes had a greater DLCO and greater D M at 80 and 90% of V˙O2 max compared to non‐athletes. However, V C was not different between groups during exercise. In contrast to our hypothesis, exercise V C was not greater in endurance‐trained subjects compared to controls; rather, the increased DLCO in athletes at peak exercise was secondary to an enhanced D M. These findings suggest that endurance‐trained athletes appear to have differences within the pulmonary membrane that facilitate the increased O2 demand needed for high‐level exercise.

Assessment of Pulmonary Capillary Blood Volume, Membrane Diffusing Capacity, and Intrapulmonary Arteriovenous Anastomoses During Exercise

“…Secondly, the number of breath holds in one session should be limited to 12, due to an increase in CO backpressure, which may affect the Vc and Dm measurement530 and pose a health risk to the subject. Depending on the research design, it may be necessary to complete the testing across multiple sessions to allow for the clearance of CO and to limit participant fatigue.…”

Marine Lipid Fraction Pcso-524™ (lyprinol®/omega-xl®) Of The New Zealand Green-lipped Mussel Does Not Improve Pulmonary And Respiratory Muscle Function In Non-asthmatic Elite Runners

“…A possible reason for decreased D LCO could be pulmonary edema due to airway inflammation during a period of high training volume, as seen acutely following an endurance exercise bout (14, 23). This could occur as a negative result of high volume training, despite increased membrane diffusing capacity and thus higher DLCO found in trained populations versus controls (33). Possible reasons for decrease in FEF 25–75 in the treatment group could be due to small airway obstruction or bronchoconstriction, although unlikely because our athletes were non-asthmatic.…”

Pushing it to the limit: enhanced diffusing membrane capacity facilitates greater pulmonary diffusing capacity in athletes during exercise

“…In conclusion, Tedjasaputra et al . () demonstrate that pulmonary diffusion capacity at near‐maximal exercise is greater in endurance‐trained male athletes compared to non‐athletes, and that this is primarily a result of enhanced diffusing membrane capacity, independent of mean pulmonary flow or alveolar volume. This adaptation permits the transfer of oxygen from the alveoli to the blood without limitation during the performance of high intensity exercise.…”

“…In a recent issue of The Journal of Physiology , Tedjasaputra et al . () endeavoured to address these knowledge gaps, and investigated the changes in DLCO, V C and D M during submaximal exercise up to 90% in a group of endurance trained athletes and a group of healthy non‐athletes. The authors hypothesized that DLCO, V C , and D M would be higher in athletes compared to non‐athletes during incremental cycling exercise.…”

“…The study design utilized by Tedjasaputra et al . () has several strengths and limitations which merit discussion. Volunteers were appropriately selected with no history of pulmonary or cardiovascular disease.…”