Catecholamine and blood lactate responses to incremental rowing and running exercise

1994 ◽  
Vol 76 (3) ◽  
pp. 1144-1149 ◽  
Author(s):  
A. Weltman ◽  
C. M. Wood ◽  
C. J. Womack ◽  
S. E. Davis ◽  
J. L. Blumer ◽  
...  

Ten collegiate rowers performed discontinuous incremental exercise to their tolerable limit on two occasions: once on a rowing ergometer and once on a treadmill. Ventilation and pulmonary gas exchange were monitored continuously, and blood was sampled from a venous catheter located in the back of the hand or forearm for determination of blood lactate ([La]) and plasma epinephrine ([Epi]) and norepinephrine ([NE]) concentrations. Thresholds for lactate (LT), epinephrine (Epi-T), and norepinephrine (NE-T) were determined for each subject under each condition and defined as breakpoints when plotted as a function of O2 uptake (VO2). For running, LT (3.76 +/- 0.18 l/min) was lower (P < 0.05) than Epi-T (4.35 +/- 0.14 l/min) and NE-T (4.04 +/- 0.19 l/min). For rowing, LT (3.35 +/- 0.16 l/min) was lower (P < 0.05) than Epi-T (3.72 +/- 0.22 l/min) and NE-T (3.70 +/- 0.18 l/min) and was lower (P < 0.05) than LT for running. Within each mode of exercise, Epi-T and NE-T did not differ. Because LT occurred at a significantly lower VO2 than either Epi-T or NE-T, we conclude that catecholamine thresholds, per se, were not the cause of LT. However, for both modes of exercise LT occurred at a plasma [Epi] of approximately 200–250 pg/ml (rowing, 221 +/- 48 pg/ml; running, 245 +/- 45 pg/ml); these concentrations are consistent with the plasma [Epi] reported necessary for eliciting increments in blood [La] during Epi infusion at rest. Plasma [NE] at LT differed significantly between modes (rowing, 820 +/- 127 pg/ml; running, 1,712 +/- 217 pg/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

2005 ◽  
Vol 10 (1) ◽  
Author(s):  
A. THOMASSIAN ◽  
M.J. WATANABE ◽  
A.L.G. ALVES ◽  
C.A. HUSSNI ◽  
J.L.M. NICOLETTI ◽  
...  

Com este estudo objetivou-se avaliar as alterações da concentração de lactato sanguíneo e determinar o V4 de cavalos da raça Árabe submetidos ao teste de exercício progressivo em esteira de alta velocidade. Onze eqüinos adultos foram submetidos a um período de condicionamento e ao teste de exercício progressivo em esteira de alta velocidade. Nas condições em que foi realizado o experimento foi possível concluir que o protocolo de exercício proposto para aplicação do teste padrão de exercício progressivo, mostrou-se eficaz na indução de respostas metabólicas e fisiológicas para várias intensidades de exercício de cavalos da raça Árabe durante o trabalho físico em esteira de alta velocidade. As concentrações de lactato sanguíneo elevam-se exponencialmente a partir da velocidade de exercício de 8,0m/s, determinada como o V4 para o presente estudo. Blood concentration of lactate and determination of V4 in Arabian horses during a incremental exercise test performed at a high-speed treadmill Abstract The purpose of this study was to evaluate the changes in the blood lactate concentrations and to determine the V4 in Arabian horses, submitted to incremental exercise test performed on a high-speed treadmill. Eleven adult horses underwent a conditioning period as well as incremental exercise test performed on a high-speed treadmill. Under the circumstances that the experiment was developed, it was possible to conclude that the results obtained during the incremental exercise test were useful to assess the horse’s metabolic capability. The blood lactate levels exponentially increase beyond the speed of 8.0 m/s, determined as the V4 for this study.


2008 ◽  
Vol 104 (3) ◽  
pp. 837-844 ◽  
Author(s):  
Babs R. Soller ◽  
Ye Yang ◽  
Stuart M. C. Lee ◽  
Cassie Wilson ◽  
R. Donald Hagan

The intensity of exercise above which oxygen uptake (V̇o2) does not account for all of the required energy to perform work has been associated with lactate accumulation in the blood (lactate threshold, LT) and elevated carbon dioxide output (gas exchange threshold). An increase in hydrogen ion concentration ([H+]) is approximately concurrent with elevation of blood lactate and CO2 output during exercise. Near-infrared spectra (NIRS) and invasive interstitial fluid pH (pHm) were measured in the flexor digitorum profundus during handgrip exercise to produce a mathematical model relating the two measures with an estimated error of 0.035 pH units. This NIRS pHm model was subsequently applied to spectra collected from the vastus lateralis of 10 subjects performing an incremental-intensity cycle protocol. Muscle oxygen saturation (SmO2) was also calculated from spectra. We hypothesized that a H+ threshold could be identified for these subjects and that it would be different from but correlated with the LT. Lactate, gas exchange, SmO2, and H+ thresholds were determined as a function of V̇o2 using bilinear regression. LT was significantly different from both the gas exchange threshold (Δ = 0.27 ± 0.29 l/min) and H+ threshold (Δ = 0.29 ± 0.23 l/min), but the gas exchange threshold was not significantly different from the H+ threshold (Δ = 0.00 ± 0.38 l/min). The H+ threshold was strongly correlated with LT ( R2 = 0.95) and the gas exchange threshold ( R2 = 0.85). This initial study demonstrates the feasibility of noninvasive pHm estimations, the determination of H+ threshold, and the relationship between H+ and classical metabolic thresholds during incremental exercise.


1996 ◽  
Vol 21 (3) ◽  
pp. 197-208 ◽  
Author(s):  
Lennart Gullstrand

Six highly trained male elite rowers performed five sets of intermittent exercise on a rowing ergometer at competition intensity. Each set consisted of eight cycles of 15 s work and 15 s rest (15/15). Each set was repeated at 30-s intervals. Oxygen uptake and heart rate were continuously measured during each set. During the period between sets, microsamples of arterialized blood were obtained and later analyzed for lactate concentration. On two separate days, each subject also performed a 6-min bout of "all-out " exercise and a continuous incremental exercise test to fatigue on the rowing ergometer. During the intermittent rowing, no significant differences were detected in any of the measured variables between sets. Heart rate, oxygen uptake, and blood lactate averaged 89, 78, and 32%, respectively, of peak values measured during the continuous incremental exercise test. It is concluded that with rowing, the investigated 15/15 intermittent exercise model demands relatively high aerobic loading and low glycolytic activity. This exercise protocol may be considered an alternative model for training which allows rowers to work for prolonged periods of time at or slightly above competition intensity. Key words: Intermittent exercise, blood lactate, heart rate, oxygen uptake


1995 ◽  
Vol 79 (4) ◽  
pp. 1134-1141 ◽  
Author(s):  
R. L. Hughson ◽  
H. J. Green ◽  
M. T. Sharratt

The interrelationships among blood lactate (La-) and plasma norepinephrine (NE) and epinephrine (Epi) were studied simultaneously with measures of ventilation (VE) and gas exchange during incremental exercise to exhaustion in nine healthy young men. We wanted to observe whether the tight coupling that exists during normoxic exercise between the concentrations of La- ([La-]) and of both NE and Epi would also be found in hypoxia (inspired O2 fraction = 0.14). In addition, we used recently advocated methods of V slope [CO2 output vs. O2 uptake (VO2)] to select the ventilatory threshold (VT) and log-log transformation of [La-] and VO2 to select the lactate threshold (LT). Peak VO2 was reduced from 4,164 +/- 184 ml/min in normoxia to 3,635 +/- 144 ml/min in hypoxia (P < 0.05). The increase in [La-] was linearly related to the increases in both NE and Epi concentrations in the normoxic and hypoxic tests (r = 0.92–0.96). Estimates of VO2 at VT were significantly greater than those at LT in both normoxia and hypoxia, but these estimates were poorly correlated (r = -0.11–0.46). VT and LT were reduced by hypoxia. Visual interpretation of the VT by examination of VE vs. VO2 and VE/VO2 vs. VO2 did not differ from the LT, but they were less than the VTs by the V-slope method (P < 0.05); yet, all were poorly correlated. The tight coupling between the increase in [La-] and the increase in plasma catecholamines might indicate a common mechanism for the increase or a causative link. VT and LT provided estimates of the general trend in the data, but the poor correlation between them questions the utility of attempting to predict one from the other.


1986 ◽  
Vol 60 (5) ◽  
pp. 1590-1598 ◽  
Author(s):  
M. D. Hammond ◽  
G. E. Gale ◽  
K. S. Kapitan ◽  
A. Ries ◽  
P. D. Wagner

Previous studies have shown both worsening ventilation-perfusion (VA/Q) relationships and the development of diffusion limitation during exercise at simulated altitude and suggested that similar changes could occur even at sea level. We used the multiple-inert gas-elimination technique to further study gas exchange during exercise in healthy subjects at sea level. Mixed expired and arterial respiratory and inert gas tensions, cardiac output, heart rate, minute ventilation, respiratory rate, and blood temperature were recorded at rest and during steady-state exercise in the following order: rest, minimal exercise (75 W), heavy exercise (300 W), heavy exercise breathing 100% O2, repeat rest, moderate exercise (225 W), and light exercise (150 W). Alveolar-to-arterial O2 tension difference increased linearly with O2 uptake (VO2) (6.1 Torr X min-1 X 1(-1) VO2). This could be fully explained by measured VA/Q inequality at mean VO2 less than 2.5 l X min-1. At higher VO2, the increase in alveolar-to-arterial O2 tension difference could not be explained by VA/Q inequality alone, suggesting the development of diffusion limitation. VA/Q inequality increased significantly during exercise (mean log SD of perfusion increased from 0.28 +/- 0.13 at rest to 0.58 +/- 0.30 at VO2 = 4.0 l X min-1, P less than 0.01). This increase was not reversed by 100% O2 breathing and appeared to persist at least transiently following exercise. These results confirm and extend the earlier suggestions (8, 21) of increasing VA/Q inequality and O2 diffusion limitation during heavy exercise at sea level in normal subjects and demonstrate that these changes are independent of the order of performance of exercise.


1984 ◽  
Vol 57 (4) ◽  
pp. 1030-1033 ◽  
Author(s):  
D. R. Seals ◽  
B. F. Hurley ◽  
J. Schultz ◽  
J. M. Hagberg

Seven men and four women (age 63 +/- 2 yr, mean +/- SD, range 61–67 yr) participated in a 12-mo endurance training program to determine the effects of low-intensity (LI) and high-intensity (HI) training on the blood lactate response to submaximal exercise in older individuals. Maximal oxygen uptake (VO2max), blood lactate, O2 uptake (VO2), heart rate (HR), ventilation (VE), and respiratory exchange ratio (R) during three submaximal exercise bouts (65–90% VO2max) were determined before training, after 6 mo of LI training, and after an additional 6 mo of HI training. VO2max (ml X kg-1 X min-1) was increased 12% after LI training (P less than 0.05), while HI training induced a further increase of 18% (P less than 0.01). Lactate, HR, VE, and R were significantly lower (P less than 0.05) at the same absolute work rates after LI training, while HI training induced further but smaller reductions in these parameters (P greater than 0.05). In general, at the same relative work rates (ie., % of VO2max) after training, lactate was lower or unchanged, HR and R were unchanged, and VO2 and VE were higher. These findings indicate that LI training in older individuals results in adaptations in the response to submaximal exercise that are similar to those observed in younger populations and that additional higher intensity training results in further but less-marked changes.


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