Stroke volume does not plateau during graded exercise in elite male distance runners

Citation
B. Zhou et al., Stroke volume does not plateau during graded exercise in elite male distance runners, MED SCI SPT, 33(11), 2001, pp. 1849-1854
Citations number
25
Categorie Soggetti
Medical Research General Topics
Journal title
MEDICINE AND SCIENCE IN SPORTS AND EXERCISE
ISSN journal
01959131 → ACNP
Volume
33
Issue
11
Year of publication
2001
Pages
1849 - 1854
Database
ISI
SICI code
0195-9131(200111)33:11<1849:SVDNPD>2.0.ZU;2-7
Abstract
Stroke volume (SV) responses during graded treadmill exercise were studied in 1) elite male distance runners (N=5), 2) male university distance runner s (N=10), and 3) male untrained university students (N=10). Methods: Cardia c output (Q)over dot and SV were determined by a modified acetylene rebreat hing procedure. Results: There were no differences in SV responses among th e three groups during the transition from rest to light exercise (P>0.05). However, the rates of change of SV during light to maximal exercise in untr ained subjects (slope = -0.1544 mL.beat(-1)) and university distance runner s (slope = 0.1041) did not change, whereas it dramatically increased (P<0.0 01) in elite distant runners (slope=0.6734). Moreover, the elite distance r unners showed a further slope increase in SV when heart rate was above 160 bpm, which resulted in an average maximal SV of 187<plus/minus>14 mL.beat(- 1) compared with 145 +/-8 and 128 +/- 14 mL.beat(-1) in the university runn ers and untrained students, respectively (P<0.001). Similarly, max (Q)over dot reached 33.8<plus/minus>2.3, 26.3 +/-1.7, and 21.3 +/-1.5 L.min(-1) in the three groups, respectively (P<0.001). On the other hand, there was a no nsignificant tendency for maximal arteriovenous oxygen content difference t o be lower in the elite athletes compared with the other groups. Conclusion : Results from university distance runners and untrained university student s support the classic observation that SV plateaus at about 40% of maximal oxygen consumption despite increasing intensity of exercise. In contrast, s troke volume in the elite athletes does not plateau but increases continuou sly with increasing intensity of exercise over the full range of the increm ental exercise test.