446
Blood Lactate Threshold Differences Between Arterialized and Venous Blood R. A. Robergs, I Chwalbinska-Moneta 'K, J• B. Mitchell, D. D. Pascoe, I Houmard, D. L. Gostill 1-luman Performance Laboratory, Ball State University, Muncie, Indiana 47306
Introduction
venous and arterialized blood. Seven endurance-trained
Various methods exist for the evaluation of exercise performance and submaximal aerobic energy production during incremental exercise. Of notable merit is the anaerobic threshold (AT), which was first introduced in 1968 by Wasserman and Mcllroy (24). Despite conjecture over the causal mechanisms of the AT concept, a concise definition is that it represents the exercise intensity corresponding to an abrupt increase in blood lactate accumulation (5, 25). More recent measurement of the inflection point of blood lactate accumulation has been termed the lactate threshold (LT) (6, 7, 18). The LT and AT measurements have been determined from lactate accumulation in both venous and arterialized blood (5, 10,
college males performed an incremental bicycle ergometer
18, 23, 25, 27).
R. A. Robergs, J. Chwalbinska-Moneta, I B. Mitchell, D. D. Pascoe, ,J. Houmard, and D. L. Costill, Blood
Lactate Threshold Differences Between Arterialized and Venous Blood. Tnt J Sports Med, Vol 11, No 6, pp 446—451, 1990.
Accepted after revision: January 30, 1990
The purpose of this study was to investigate the differences between lactate thresholds determined from exercise test until exhaustion. At the end of each 3 mm stage,
blood was sampled simultaneously from a hyperemized ear-lobe and an antecubital vein for the measurement of blood lactate (La-). Two-minute rest intervals separated each stage. Arterialized blood La-concentrations ([La-]) were significantly higher than venous blood at 350 W (14.5
and 9.7 mmoll'), maximal exercise (15.5 and 11.39 mmoll 1), and throughout recovery. Arterialized [La-] was significantly higher than venous blood at the onset of
blood La- accumulation (OBLA) (4.0 and 2.8±0.1
mmoll — 1), the individual anaerobic threshold (IAT)
(3.4±0.3 and 2.1 mmollt), and the ventilatory threshold (VT) (4.7±0.9 and 3.2±0.6 mmol-L1). No
In addition to the AT methods of exercise per-
formance evaluation, Kindermann et a!. (14) proposed a 4 mmoll — 1 fixed blood lactate threshold. Sjödin and Jacobs (21) referred to this method as the onset of blood lactate accu-
mulation (OBLA). These fixed blood lactate tests were initially derived from arterialized blood lactate measurements attained from incremental exercise involving stage durations in excess of three minutes (9, 14, 23). The OBLA testing protocol identified that an arterialized blood lactate concentration of 4 mmol l — represented the upper threshold of steady state energy metabolism (9).
significant differences were found between either La-thre-
Another method has been proposed by Steg-
shold for arterialized or venous blood. The oxygen con-
2.8 0.2 lmin 1). No significant differences existed be-
man et al. (23). These authors measured arterialized blood lactate, and determined the AT from the time course of lactate accumulation and removal. This method has been termed the individual anaerobic threshold (TAT). Interestingly, each of the
tween the LT, OBLA, and TAT threshold-V02 determinations from arterialized blood; however, significant differ-
LT, OBLA, and TAT methods of AT detection have been shown to correlate highly with endurance exercise perform-
sumption (V02) at OBLA was significantly lower when de-
termined from arterialized blood La (2.3 0.2 and
ences were found between IAT-OBLA (2.1±0.2 and
2.8±0.2 lmin1) and LT (2.2±0.2 lmin')-OBLA from venous blood. These results indicate that differences between venous and arterialized blood [La-] need to be considered when comparing different anaerobic threshold determinations.
ance (14, 20, 21, 25).
Considerable research has focussed on dietary and acid-base causes for differences between blood lactate and/or ventilatory methods used to evaluate blood lactate accumulation (18, 27, 28). The discrepancies that have been detected may be attributed to differing test procedures and/or
Key words
Onset of blood lactate accumulation, individual anaerobic threshold, ventilatory threshold, lactate
uptake mt. J. Sports Med. 11(1990)446—451
GeorgThieme Verlag StuttgartNew York
* J.
Chwalbinska-Moneta, M. D., was a visiting Fellow of the
National Research Council, National Academy of Sciences and Polish Academy of Sciences. Current address; Department of Applied Physiology, Medical Research Centre, Polish Academy of Sciences, 17 Jazgarzewska St., 00-730 Warsaw, Poland.
Downloaded by: Queen's University. Copyrighted material.
Abstract
mt. J. Sports Med. 11(1990) 447
Blood Lactate Threshold D jfferences Between Arterialized and Venous Blood
Fig. 1 Blood lactate and ventilatory data
SUBJECT # 1
0 C.) Ui
.> C4
40 36
mmoll _1), individual anaerobic threshold (IAT= 2.8 and 2.4 mmol1 1), and onset of blood lactate accumulation (OBLA). The VT was detected from the ventilatory equiv-
F VENCO2
32 28
0
24
w
20
->
for subject #1. Arterialized and venous blood lactate values were determined for the lactate threshold (LT=1.4 and 1.6
D
.
VT
a
F
alent of oxygen (VE/VEO2) and carbon dioxide (VE/VCO2). During exercise, the exponential correlations between lactate and time for arterialized and venous blood were 1.0 and 0.98, respectively
F
arterialized blood venous blood
14 12
10•
x
8
6 E
2
12 15 18 2
0 Exercise
5
10
15
Recovery
TIME (mm) Table 1 Descriptive characteris tics of the subjects
Mean S. E.
Variable
25.7± 1.5
Age (yr) Height (cm) Weight (kg)
183.6
1.3
74.8±2.3 12.1±0.7
%Fat
VOmax (lmin1) Power output max (W)
3.9±0.2 357.1
different causal mechanisms. In addition, as the LI is usually derived from venous lactate accumulation, and the OBLA and IAT methods are derived from arterialized blood lactate concentrations, additional error may reside in lactate accumulation differences between arterialized and venous blood (1, 2, 19, 27). These differences may add to the uncertainty of detecting a lactate threshold value.
Limited evaluation of arterialized and venous blood lactate accumulation differences during progressive exercise have been performed (2, 19, 27). Consequently, the purpose of this study was to compare arterialized capillary and venous blood lactate concentrations during incremental exercise, and to contrast measurements of the LT, OBLA, IAT, and VT.
Methods
Subjects Seven endurance-trained males of varied aerobic fitness volunteered for this study. The physical characteristics and maximal exercise data for these subjects are presented in Table 1. Prior to testing, each subject was informed of
the risks, benefits, and procedures of the study before giving their written informed consent.
Experimental Protocol The subjects participated in an incremental ex-
ercise test conducted on an electronically braked bicycle ergometer. Each test started with a load of 50W at 60rpm for 3 mm, followed by a 2 mm rest interval. Subsequent loads were then increased by 50 W, with a 3 mm stage duration and 2 mm recovery repeated until exhaustion. Respiratory gas exchange
was analyzed continuously and computed every 30 s during each stage of exercise using an Applied Electrochemistry S-3A 02 analyzer and a Beckman LB-2 C02 analyzer integrated to a computer-based system. Heart rates were obtained by a radiotelemetry system (Quantum-XL). During cycling, subjects placed their forearms
on a padded rest positioned over the handlebars. A teflon catheter was placed percutaneously into an antecubital vein of
a forearm, and was kept patent by allowing free blood flow into a reserve syringe. Arterialized blood was sampled from a hyperemized ear-lobe. Blood was sampled for lactate determination simultaneously from the antecubital vein and ear-lobe at rest, immediately after each exercise stage, and at 2, 5, 10, and 15 mm post-exercise.
The methods of AT detection for subject 1 are illustrated in Fig. 1. The exponential increase in blood lactate
concentration made a linear based determination of the LI difficult. Consequently, since exponential correlations between time and lactate in either blood compartment were above 0.90, blood lactate accumulation in arterialized and venous blood was treated as an exponential function. Transformation of the increasing blood lactate concentrations to log values produced a linear log La - V02 (1-min 1) plot (Fig. 2) (26). A log-log model (log La - log V02) resulted in a two segment linear regression determination of each venous and arterialized blood LT (Fig. 3). The LT was determined as the point of intercept between each lower and upper regression line (3).
Downloaded by: Queen's University. Copyrighted material.
I AT
U
448 mt. J. Sports Med. 11 (1990)
R. A. Robergs, .1. Chwalbinska-Moneta, J. B. Mitchell, D. D. Pascoe, J. Houmard, F. L. Costill Fig. 2 The relationship between blood lac-
tate concentrations expressed as log values (log [La-I) and oxygen consumption (V02) during progressive exercise
1 0)
0
-J
0.0
0.5
1.5
1.0
2.0
3.0
2.5
3.5
4.0
4.5
Fig. 3 The relationship between blood lactate concentrations and oxygen consumption when both are expressed as log values (log [La-I and log V02). The V02 at the intercept of the two lines for each blood compart-
ment represented the lactate thresholds (LT)
-j C)
0
-J
0
0.1
0.2
0.3
log
0.4
0.5
0.6
O2
The AT was also determined at a fixed blood lactate concentration of 4 mmolF 1(0BLA) (14), at the individual anaerobic threshold (IAT) (20, 23), and ventilatory threshold. The ventilatory threshold (Vi') was detected from plots of minute ventilation and the ventilatory eyuivalents of oxygen and carbon dioxide (VE/ V02 and VEt VCO2, respectively) at each stage according to the criteria of Wasserman et al. (25) and Davis et al. (5). The IAT was detected by graphing
blood lactate concentrations during exercise and recovery,
and the point where the recovery lactate concentration equalled blood lactate at maximal exercise was determined. A tangent line was then drawn connecting this point to the arterialized blood lactate accumulation curve (20, 23). The point of intercept was the IAT (Fig. 1).
centrifuged, and stored at —20 °C for subsequent spectrophotometric analysis of lactate (17).
Statistical Analyses
Differences between the arterialized and venous AT measurements were evaluated by 2-way ANOVA with repeated measures. Selected post-hoc comparisons were tested for significant differences using 1-way ANOVA with appropriate repeated factor error terms, and the Tukey test.
Additional differences between means were tested using a paired t-test. Significance was set at the 0.05 level of confidence. All data are reported as means standard error (SE). Results
Analytical Techniques Blood samples (25 .iI) for lactate determination were immediately deproteinized in perchioric acid (8%),
Comparisons between mean values for lactate accumulation are illustrated in Fig. 4. Arterialized lactate con-
centrations increased at a greater rate than venous lactate during the progressive exercise test, and was significantly
Downloaded by: Queen's University. Copyrighted material.
x min 1)
mt. J. Sports Med. 11(1990) 449
Blood Lact ate Threshold D jfferences Between Arterialized and Venous Blood
Fig. 4 Lactate accumulation in arterialized and venous blood during progressive exercise and recovery. * = p
Blood Lactate Threshold Differences Between Arterialized and Venous Blood R. A. Robergs, I Chwalbinska-Moneta 'K, J• B. Mitchell, D. D. Pascoe, I Houmard, D. L. Gostill 1-luman Performance Laboratory, Ball State University, Muncie, Indiana 47306
Introduction
venous and arterialized blood. Seven endurance-trained
Various methods exist for the evaluation of exercise performance and submaximal aerobic energy production during incremental exercise. Of notable merit is the anaerobic threshold (AT), which was first introduced in 1968 by Wasserman and Mcllroy (24). Despite conjecture over the causal mechanisms of the AT concept, a concise definition is that it represents the exercise intensity corresponding to an abrupt increase in blood lactate accumulation (5, 25). More recent measurement of the inflection point of blood lactate accumulation has been termed the lactate threshold (LT) (6, 7, 18). The LT and AT measurements have been determined from lactate accumulation in both venous and arterialized blood (5, 10,
college males performed an incremental bicycle ergometer
18, 23, 25, 27).
R. A. Robergs, J. Chwalbinska-Moneta, I B. Mitchell, D. D. Pascoe, ,J. Houmard, and D. L. Costill, Blood
Lactate Threshold Differences Between Arterialized and Venous Blood. Tnt J Sports Med, Vol 11, No 6, pp 446—451, 1990.
Accepted after revision: January 30, 1990
The purpose of this study was to investigate the differences between lactate thresholds determined from exercise test until exhaustion. At the end of each 3 mm stage,
blood was sampled simultaneously from a hyperemized ear-lobe and an antecubital vein for the measurement of blood lactate (La-). Two-minute rest intervals separated each stage. Arterialized blood La-concentrations ([La-]) were significantly higher than venous blood at 350 W (14.5
and 9.7 mmoll'), maximal exercise (15.5 and 11.39 mmoll 1), and throughout recovery. Arterialized [La-] was significantly higher than venous blood at the onset of
blood La- accumulation (OBLA) (4.0 and 2.8±0.1
mmoll — 1), the individual anaerobic threshold (IAT)
(3.4±0.3 and 2.1 mmollt), and the ventilatory threshold (VT) (4.7±0.9 and 3.2±0.6 mmol-L1). No
In addition to the AT methods of exercise per-
formance evaluation, Kindermann et a!. (14) proposed a 4 mmoll — 1 fixed blood lactate threshold. Sjödin and Jacobs (21) referred to this method as the onset of blood lactate accu-
mulation (OBLA). These fixed blood lactate tests were initially derived from arterialized blood lactate measurements attained from incremental exercise involving stage durations in excess of three minutes (9, 14, 23). The OBLA testing protocol identified that an arterialized blood lactate concentration of 4 mmol l — represented the upper threshold of steady state energy metabolism (9).
significant differences were found between either La-thre-
Another method has been proposed by Steg-
shold for arterialized or venous blood. The oxygen con-
2.8 0.2 lmin 1). No significant differences existed be-
man et al. (23). These authors measured arterialized blood lactate, and determined the AT from the time course of lactate accumulation and removal. This method has been termed the individual anaerobic threshold (TAT). Interestingly, each of the
tween the LT, OBLA, and TAT threshold-V02 determinations from arterialized blood; however, significant differ-
LT, OBLA, and TAT methods of AT detection have been shown to correlate highly with endurance exercise perform-
sumption (V02) at OBLA was significantly lower when de-
termined from arterialized blood La (2.3 0.2 and
ences were found between IAT-OBLA (2.1±0.2 and
2.8±0.2 lmin1) and LT (2.2±0.2 lmin')-OBLA from venous blood. These results indicate that differences between venous and arterialized blood [La-] need to be considered when comparing different anaerobic threshold determinations.
ance (14, 20, 21, 25).
Considerable research has focussed on dietary and acid-base causes for differences between blood lactate and/or ventilatory methods used to evaluate blood lactate accumulation (18, 27, 28). The discrepancies that have been detected may be attributed to differing test procedures and/or
Key words
Onset of blood lactate accumulation, individual anaerobic threshold, ventilatory threshold, lactate
uptake mt. J. Sports Med. 11(1990)446—451
GeorgThieme Verlag StuttgartNew York
* J.
Chwalbinska-Moneta, M. D., was a visiting Fellow of the
National Research Council, National Academy of Sciences and Polish Academy of Sciences. Current address; Department of Applied Physiology, Medical Research Centre, Polish Academy of Sciences, 17 Jazgarzewska St., 00-730 Warsaw, Poland.
Downloaded by: Queen's University. Copyrighted material.
Abstract
mt. J. Sports Med. 11(1990) 447
Blood Lactate Threshold D jfferences Between Arterialized and Venous Blood
Fig. 1 Blood lactate and ventilatory data
SUBJECT # 1
0 C.) Ui
.> C4
40 36
mmoll _1), individual anaerobic threshold (IAT= 2.8 and 2.4 mmol1 1), and onset of blood lactate accumulation (OBLA). The VT was detected from the ventilatory equiv-
F VENCO2
32 28
0
24
w
20
->
for subject #1. Arterialized and venous blood lactate values were determined for the lactate threshold (LT=1.4 and 1.6
D
.
VT
a
F
alent of oxygen (VE/VEO2) and carbon dioxide (VE/VCO2). During exercise, the exponential correlations between lactate and time for arterialized and venous blood were 1.0 and 0.98, respectively
F
arterialized blood venous blood
14 12
10•
x
8
6 E
2
12 15 18 2
0 Exercise
5
10
15
Recovery
TIME (mm) Table 1 Descriptive characteris tics of the subjects
Mean S. E.
Variable
25.7± 1.5
Age (yr) Height (cm) Weight (kg)
183.6
1.3
74.8±2.3 12.1±0.7
%Fat
VOmax (lmin1) Power output max (W)
3.9±0.2 357.1
different causal mechanisms. In addition, as the LI is usually derived from venous lactate accumulation, and the OBLA and IAT methods are derived from arterialized blood lactate concentrations, additional error may reside in lactate accumulation differences between arterialized and venous blood (1, 2, 19, 27). These differences may add to the uncertainty of detecting a lactate threshold value.
Limited evaluation of arterialized and venous blood lactate accumulation differences during progressive exercise have been performed (2, 19, 27). Consequently, the purpose of this study was to compare arterialized capillary and venous blood lactate concentrations during incremental exercise, and to contrast measurements of the LT, OBLA, IAT, and VT.
Methods
Subjects Seven endurance-trained males of varied aerobic fitness volunteered for this study. The physical characteristics and maximal exercise data for these subjects are presented in Table 1. Prior to testing, each subject was informed of
the risks, benefits, and procedures of the study before giving their written informed consent.
Experimental Protocol The subjects participated in an incremental ex-
ercise test conducted on an electronically braked bicycle ergometer. Each test started with a load of 50W at 60rpm for 3 mm, followed by a 2 mm rest interval. Subsequent loads were then increased by 50 W, with a 3 mm stage duration and 2 mm recovery repeated until exhaustion. Respiratory gas exchange
was analyzed continuously and computed every 30 s during each stage of exercise using an Applied Electrochemistry S-3A 02 analyzer and a Beckman LB-2 C02 analyzer integrated to a computer-based system. Heart rates were obtained by a radiotelemetry system (Quantum-XL). During cycling, subjects placed their forearms
on a padded rest positioned over the handlebars. A teflon catheter was placed percutaneously into an antecubital vein of
a forearm, and was kept patent by allowing free blood flow into a reserve syringe. Arterialized blood was sampled from a hyperemized ear-lobe. Blood was sampled for lactate determination simultaneously from the antecubital vein and ear-lobe at rest, immediately after each exercise stage, and at 2, 5, 10, and 15 mm post-exercise.
The methods of AT detection for subject 1 are illustrated in Fig. 1. The exponential increase in blood lactate
concentration made a linear based determination of the LI difficult. Consequently, since exponential correlations between time and lactate in either blood compartment were above 0.90, blood lactate accumulation in arterialized and venous blood was treated as an exponential function. Transformation of the increasing blood lactate concentrations to log values produced a linear log La - V02 (1-min 1) plot (Fig. 2) (26). A log-log model (log La - log V02) resulted in a two segment linear regression determination of each venous and arterialized blood LT (Fig. 3). The LT was determined as the point of intercept between each lower and upper regression line (3).
Downloaded by: Queen's University. Copyrighted material.
I AT
U
448 mt. J. Sports Med. 11 (1990)
R. A. Robergs, .1. Chwalbinska-Moneta, J. B. Mitchell, D. D. Pascoe, J. Houmard, F. L. Costill Fig. 2 The relationship between blood lac-
tate concentrations expressed as log values (log [La-I) and oxygen consumption (V02) during progressive exercise
1 0)
0
-J
0.0
0.5
1.5
1.0
2.0
3.0
2.5
3.5
4.0
4.5
Fig. 3 The relationship between blood lactate concentrations and oxygen consumption when both are expressed as log values (log [La-I and log V02). The V02 at the intercept of the two lines for each blood compart-
ment represented the lactate thresholds (LT)
-j C)
0
-J
0
0.1
0.2
0.3
log
0.4
0.5
0.6
O2
The AT was also determined at a fixed blood lactate concentration of 4 mmolF 1(0BLA) (14), at the individual anaerobic threshold (IAT) (20, 23), and ventilatory threshold. The ventilatory threshold (Vi') was detected from plots of minute ventilation and the ventilatory eyuivalents of oxygen and carbon dioxide (VE/ V02 and VEt VCO2, respectively) at each stage according to the criteria of Wasserman et al. (25) and Davis et al. (5). The IAT was detected by graphing
blood lactate concentrations during exercise and recovery,
and the point where the recovery lactate concentration equalled blood lactate at maximal exercise was determined. A tangent line was then drawn connecting this point to the arterialized blood lactate accumulation curve (20, 23). The point of intercept was the IAT (Fig. 1).
centrifuged, and stored at —20 °C for subsequent spectrophotometric analysis of lactate (17).
Statistical Analyses
Differences between the arterialized and venous AT measurements were evaluated by 2-way ANOVA with repeated measures. Selected post-hoc comparisons were tested for significant differences using 1-way ANOVA with appropriate repeated factor error terms, and the Tukey test.
Additional differences between means were tested using a paired t-test. Significance was set at the 0.05 level of confidence. All data are reported as means standard error (SE). Results
Analytical Techniques Blood samples (25 .iI) for lactate determination were immediately deproteinized in perchioric acid (8%),
Comparisons between mean values for lactate accumulation are illustrated in Fig. 4. Arterialized lactate con-
centrations increased at a greater rate than venous lactate during the progressive exercise test, and was significantly
Downloaded by: Queen's University. Copyrighted material.
x min 1)
mt. J. Sports Med. 11(1990) 449
Blood Lact ate Threshold D jfferences Between Arterialized and Venous Blood
Fig. 4 Lactate accumulation in arterialized and venous blood during progressive exercise and recovery. * = p
