title: Acute reduction in maximal oxygen uptake after long-distance running.
abstract: Nine male marathon runners, 24 to 39 years of age, were studied during steady state and maximal graded treadmill exercise under control conditions (C) and immediately after a paced outdoor 21.1-km run averaging 89.5 min (E). The half-marathon run and both treadmill trials were performed at 239 +/- 33 m/min. Oxygen uptake (VO2), respiratory exchange ratio (RER), heart rate (HR), plasma lactate concentration (PLa), and rating of perceived exertion (RPE) were measured in the steady state at 0% grade and at the fatigue end point. Compared to C, mean values in E were significantly lower (p less than 0.05) for time to exhaustion (6.0 vs 4.1 min), VO2max (60.0 vs 56.3 ml/kg/min), peak RER (1.18 vs 1.06), and PLa (9.7 vs 7.8 mM/L), whereas maximal HR (184 vs 184 b/min) and peak RPE (19.6 vs 19.9) were not significantly different between trials. Submaximal VO2 during steady-state runs was similar between C and E (44.4 vs 45.0 ml/kg/min; p = NS). Since the attainable VO2max decreased after E, the percentage of VO2max utilized during steady-state runs was higher, averaging 74% in C and 80% in E (p less than 0.05). In the steady state during E, HR (153 vs 161 b/min) and RPE (13.2 vs 14.8) were higher (p less than 0.05), and the increase in PLa from rest (2.7 vs 1.9 mM/L) was lower (p less than 0.05). Submaximal HR during graded exercise in E was 7 to 8 b/min higher (p less than 0.05) at a given VO2, indicating reduced heart rate reserve.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Human Performance & Sport, New Mexico Highlands University, Las Vegas 87701.
authors.forename: R H
authors.initials: RH
authors.lastname: Dressendorfer
mesh_terms: D000328:Adult; D006339:Heart Rate; D006801:Humans; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008297:Male; D010101:Oxygen Consumption; D010465:Perception; D005082:Physical Exertion / Q000502:physiology*; D012044:Regression Analysis; D012119:Respiration; D012420:Running; D013647:Task Performance and Analysis; D013997:Time Factors
chemical_list: D007773:Lactates; D019344:Lactic Acid