Non-invasive detection of the anaerobic threshold by a neural network model of the heart rate—work rate relationship

2009 ◽  
Vol 223 (3) ◽  
pp. 109-115 ◽  
Author(s):  
A Erdogan ◽  
C Cetin ◽  
H Goksu ◽  
R Guner ◽  
M L Baydar
Keyword(s):  
Neural Network ◽  
Heart Rate ◽  
Blood Lactate ◽  
Test Data ◽  
Anaerobic Threshold ◽  
External Validation ◽  
Lactate Concentration ◽  
Work Rate ◽  
Non Invasive ◽  
Rate Relationship

The heart rates (HRs) indicating the anaerobic threshold, which corresponds to a fixed blood lactate concentration of 4mmol/l (heart rate at the onset of blood lactate accumulation (HR-OBLA)); are predicted on the basis of the heart rate—work rate relationship during exercise performance. The predictor is a multi-layer perceptron (MLP). For training and testing, 225 male soccer players (mean age, 21.6±4.5 years) performed an incremental running test on a treadmill with 3-min runs and 30-s blood sampling sessions for lactate assessment. In addition to the treadmill test data, the ages, masses, heights, body mass indices, and playing positions of half of the subjects ( n=113) were used to train the MLP and the remaining 112 were used for external validation. The results showed that the HR values recorded in the last stages before exhaustion were strong predictors of HR-OBLA ( r=0.875; standard error of estimates, 4.17). Inclusion of other parameters did not improve the prediction rate. Although additional work is needed to generalize the method to training prescription, results suggest that a neural network is a promising non-invasive tool for accurately estimating the HR-OBLA from exercise test data.

Lactate removal ability and graded exercise in humans

1990 ◽  
Vol 68 (3) ◽  
pp. 905-911 ◽  
Author(s):  
S. Oyono-Enguelle ◽  
J. Marbach ◽  
A. Heitz ◽  
C. Ott ◽  
M. Gartner ◽  
...  
Keyword(s):  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Inverse Correlation ◽  
Continuous Model ◽  
Work Rate ◽  
Linear Relationships ◽  
Graded Exercise ◽  
Lactate Removal ◽  
The Individual

Venous lactate concentrations of nine athletes were recorded every 5 s before, during, and after graded exercise beginning at a work rate of 0 W with an increase of 50 W every 4th min. The continuous model proposed by Hughson et al. (J. Appl. Physiol. 62: 1975-1981, 1987) was well fitted with the individual blood lactate concentration vs. work rate curves obtained during exercise. Time courses of lactate concentrations during recovery were accurately described by a sum of two exponential functions. Significant direct linear relationships were found between the velocity constant (gamma 2 nu) of the slowly decreasing exponential term of the recovery curves and the times into the exercise when a lactate concentration of 2.5 mmol/l was reached. There was a significant inverse correlation between gamma 2 nu and the rate of lactate increase during the last step of the exercise. In terms of the functional meaning given to gamma 2 nu, these relationships indicate that the shift to higher work rates of the increase of the blood lactate concentration during graded exercise in fit or trained athletes, when compared with less fit or untrained ones, is associated with a higher ability to remove lactate during the recovery. The results suggest that the lactate removal ability plays an important role in the evolution pattern of blood lactate concentrations during graded exercise.

Exercise recovery above and below anaerobic threshold following maximal work

1981 ◽  
Vol 51 (4) ◽  
pp. 840-844 ◽  
Author(s):  
B. A. Stamford ◽  
A. Weltman ◽  
R. Moffatt ◽  
S. Sady
Keyword(s):  
Blood Lactate ◽  
Anaerobic Threshold ◽  
Maximal Exercise ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Base Line ◽  
Exercise Recovery ◽  
O2 Uptake ◽  
Vo2 Max ◽  
Individual Subject

The purpose of this study was to determine the effects of resting and exercise recovery above [70% of maximum O2 uptake (VO2 max)] and below [40% of VO2 max] anaerobic threshold (AT) on blood lactate disappearance following maximal exercise. Blood lactate concentrations at rest (0.9 mM) and during exercise at 40% (1.3 mM) and 70% (3.5 mM) of VO2 max without preceding maximal exercise were determined on separate occasions and represented base lines for each condition. The rate of blood lactate disappearance from peak values was ascertained from single-component exponential curves fit for each individual subject for each condition using both the determined and resting base lines. When determined base lines were utilized, there were no significant differences in curve parameters between the 40 and 70% of VO2 max recoveries, and both were significantly different from the resting recovery. When a resting base line (0.9 mM) was utilized for all conditions, 40% of VO2 max demonstrated a significantly faster half time than either 70% of VO2 max or resting recovery. No differences were found between 70% of VO2 max and resting recovery. It was concluded that interpretation of the effectiveness of exercise recovery above and below AT with respect to blood lactate disappearance is influenced by the base-line blood lactate concentration utilized in the calculation of exponential half times.

Association between the anaerobic threshold and the break-point in the double product/work rate relationship

1996 ◽  
Vol 75 (1) ◽  
pp. 14-21 ◽  
Author(s):  
M. Riley ◽  
K. Maehara ◽  
J. P�rsz�sz ◽  
M. P. K. J. Engelen ◽  
H. Tanaka ◽  
...  
Keyword(s):  
Anaerobic Threshold ◽  
Break Point ◽  
Work Rate ◽  
Double Product ◽  
Rate Relationship

Exercise in Merino sheep dash the relationships between work intensity, endurance, anaerobic threshold and glucose metabolism

1991 ◽  
Vol 42 (4) ◽  
pp. 599 ◽  
Author(s):  
DW Pethick ◽  
CB Miller ◽  
NG Harman
Keyword(s):  
Glucose Metabolism ◽  
Anaerobic Threshold ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Work Load ◽  
Respiratory Alkalosis ◽  
Work Rate ◽  
Glycerol Concentration ◽  
Work Intensity ◽  
Intensity Of Exercise

The effect of exercise intensity on (i) the ability of sheep to sustain exercise and (ii) glucose metabolism was investigated in fed non-pregnant adult Merino ewes. Five animals were prepared with cannulae to study the splanchnic tissues using the arteriovenous difference technique either at rest or during 8 levels of exercise: 3, 5, 7 and 9 km h-1 at either 0� or 9� incline. The anaerobic threshold, determined by elevation of blood lactate concentration or lactate/pyruvate ratio, occurred at a work rate of about 6-10 watts/kg body wt (7 km h-1 on 0� incline, 3 km h-1 on 9� incline). Only exercise well in excess of the anaerobic threshold resulted in ewes showing fatigue. Fatigue was not associated with carbohydrate depletion or lacticacidosis. Changes in the partial pressure of CO2 and the pH of blood indicated a marked respiratory alkalosis that was related to the severity of exercise, suggesting that thermoregulation may have been an important component of fatigue. Splanchnic blood flow declined when the intensity of exercise exceeded the anaerobic threshold; however, this did not compromise splanchnic function as assessed by oxygen and metabolite uptake. During exercise below the anaerobic threshold euglycemia was maintained while a pronounced hyperglycemia, that became more severe as the work rate increased, was found for exercise above the anaerobic threshold. The release of glucose by the liver increased significantly at all work rates and markedly so after the anaerobic threshold, such that the resultant hyperglycemia was consistent with an exaggerated hepatic glucose release due to 'feed forward' control. The contribution of lactate and glycerol to gluconeogenesis, assuming complete conversion, remained constant at 18-25% except at the highest work load where the contribution significantly declined to 9%. The decline was due to (i) saturation of hepatic lactate uptake and (ii) a failure for glycerol concentration and so uptake to increase beyond a work rate of 22 W kg-1. The requirement for gluconeogenic end products of digestion for animals grazed under extensive conditions would be 9-30% greater than for animals not exercising, depending upon the speed and inclination of exercise.

scholarly journals HRV (Heart Rate Variability) as a non-invasive measurement method for performance diagnostics and training control

2019 ◽  
Vol 5 (1) ◽  
pp. 97-100 ◽  
Author(s):  
Matthias Scherer ◽  
Johannes Martinek ◽  
Winfried Mayr
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Athletic Performance ◽  
Lactate Concentration ◽  
Bicycle Ergometer ◽  
Step Test ◽  
Total Power ◽  
Plateau Phase ◽  
Test Procedures ◽  
Non Invasive

AbstractThe aim of this study was to determine whether non-invasive heart rate variability (HRV) recordings can be used to monitor training exercises and to estimate athletic performance. Thus far, condition and performance have been evaluated with lactate test procedures and spirometry. Several tests were conducted to determine the relationship of data from lactate test samplings, spirometry and HRV recordings. Four groups of professional athletes in different disciplines such as ball sports (n=15), martial arts (n=17), endurance sports (n=8) and hobby athletes (n=6) underwent a standardized treadmill or bicycle ergometer step test while increasing load rates, e.g. 2 km/h or 20-50 Watt every 3.5 minutes, synchronized with standardized series of lactate test sampling, spirometry and ECG recording. An inclusion criterion for all athlete groups was a minimum training frequency of an hour, five days a week focusing on continuous performance improvement. Evidence shows that offline analysis of ECG data allows conclusions on actual individual athletic performance without the need for complex instrumentation and laboratory environment. The total power parameter of the HRV reaches a plateau phase in all tested subjects and this plateau phase reaches zero near the 2 mmol threshold of lactate concentration in all subjects recorded on a bicycle ergometer. Nine out of ten subjects measured on the bicycle ergometer had negatively correlating data of lactate concentration and total power of HRV (α < 0.05). Lactate measurements using treadmills require resting periods for blood sampling. As the HRV increases instantly in these resting periods, the use of bicycle ergometers, where no testing breaks are needed, is recommended for further research.

scholarly journals Effects of a 2-km Swim on Markers of Cycling Performance in Elite Age-Group Triathletes

Sports ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 82
Author(s):  
Jeffrey Rothschild ◽  
George H. Crocker
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Blood Lactate ◽  
Peak Power ◽  
Maximal Oxygen Consumption ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Cycling Performance ◽  
Age Group

The purpose of this study was to examine the effects of a 2-km swim on markers of subsequent cycling performance in well-trained, age-group triathletes. Fifteen participants (10 males, five females, 38.3 ± 8.4 years) performed two progressive cycling tests between two and ten days apart, one of which was immediately following a 2-km swim (33.7 ± 4.1 min). Cycling power at 4-mM blood lactate concentration decreased after swimming by an average of 3.8% (p = 0.03, 95% CI −7.7, 0.2%), while heart rate during submaximal cycling (220 W for males, 150 W for females) increased by an average of 4.0% (p = 0.02, 95% CI 1.7, 9.7%), compared to cycling without prior swimming. Maximal oxygen consumption decreased by an average of 4.0% (p = 0.01, 95% CI −6.5, −1.4%), and peak power decreased by an average of 4.5% (p < 0.01, 95% CI −7.3, −2.3%) after swimming, compared to cycling without prior swimming. Results from this study suggest that markers of submaximal and maximal cycling are impaired following a 2-km swim.

Determination of the anaerobic threshold by a noninvasive field test in runners

1982 ◽  
Vol 52 (4) ◽  
pp. 869-873 ◽  
Author(s):  
F. Conconi ◽  
M. Ferrari ◽  
P. G. Ziglio ◽  
P. Droghetti ◽  
L. Codeca
Keyword(s):  
Heart Rate ◽  
Blood Lactate ◽  
Field Test ◽  
Anaerobic Threshold ◽  
Initial Velocity ◽  
Running Speed ◽  
The Relationship

The relationship between running speed (RS) and heart rate (HR) was determined in 210 runners. On a 400-m track the athletes ran continuously from an initial velocity of 12–14 km/h to submaximal velocities varying according to the athlete's capability. The HRs were determined through ECG. In all athletes examined, a deflection from the expected linearity of the RS-HR relationship was observed at submaximal RS. The test-retest correlation for the velocities at which this deflection from linearity occurred (Vd) determined in 26 athletes was 0.99. The velocity at the anaerobic threshold (AT), established by means of blood lactate measurements, and Vd were coincident in 10 runners. The correlation between Vd and average running speed (mean RS) in competition was 0.93 in the 5,000 m (mean Vd = 19.13 +/- 1.08 km/h; mean RS = 20.25 +/- 1.15 km/h), 0.95 in the marathon (mean Vd = 18.85 +/- 1.15 km/h; mean RS = 17.40 +/- 1.14 km/h), and 0.99 in the 1-h race (mean Vd = 18.70 +/- 0.98 km/h; mean RS = 18.65 +/- 0.92 km/h), thus showing that AT is critical in determining the running pace in aerobic competitive events.

scholarly journals Fetal heart rate short term variation during labor in relation to scalp blood lactate concentration

2018 ◽  
Vol 97 (10) ◽  
pp. 1274-1280 ◽  
Author(s):  
Ke Lu ◽  
Malin Holzmann ◽  
Fahrad Abtahi ◽  
Kaj Lindecrantz ◽  
Pelle G Lindqvist ◽  
...  
Keyword(s):  
Heart Rate ◽  
Blood Lactate ◽  
Fetal Heart Rate ◽  
Fetal Heart ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Short Term ◽  
Term Variation
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