scholarly journals A novel device for detecting anaerobic threshold using sweat lactate during exercise

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuta Seki ◽  
Daisuke Nakashima ◽  
Yasuyuki Shiraishi ◽  
Toshinobu Ryuzaki ◽  
Hidehiko Ikura ◽  
...  
Keyword(s):  
Lactate Threshold ◽  
Ventilatory Threshold ◽  
Recovery Period ◽  
Lactate Concentration ◽  
Continuous Increase ◽  
Mean Values ◽  
Additional Information ◽  
Novel Device ◽  
Mean Differences ◽  
Lactate Sensor

AbstractThe lactate threshold (LT1), which is defined as the first rise in lactate concentration during incremental exercise, has not been non-invasively and conveniently determined in a clinical setting. We aimed to visualize changes in lactate concentration in sweat during exercise using our wearable lactate sensor and investigate the relationship between the lactate threshold (LT1) and ventilatory threshold (VT1). Twenty-three healthy subjects and 42 patients with cardiovascular diseases (CVDs) were enrolled. During exercise, the dynamic changes in lactate values in sweat were visualized in real-time with a sharp continuous increase up to volitional exhaustion and a gradual decrease during the recovery period. The LT1 in sweat was well correlated with the LT1 in blood and the VT1 (r = 0.92 and 0.71, respectively). In addition, the Bland–Altman plot described no bias between the mean values (mean differences: − 4.5 and 2.5 W, respectively). Continuous monitoring of lactate concentrations during exercise can provide additional information for detecting the VT1.

Abstract 13134: A Novel Device for Detecting Anaerobic Threshold Using Sweat Lactate Acid During Exercise

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Yuta Seki ◽  
Daisuke Nakashima ◽  
Ryuzaki Toshinobu ◽  
Hidehiko Ikura ◽  
Kotaro Miura ◽  
...  
Keyword(s):  
Real Time ◽  
Healthy Subjects ◽  
Time Series Data ◽  
Ventilatory Threshold ◽  
Recovery Period ◽  
Series Data ◽  
Exercise Tests ◽  
Continuous Increase ◽  
The Mean ◽  
Lactate Sensor

Background: Continuous monitoring of lactate acid (LA) levels during exercise has not been possible. We aimed to visualize real-time changes in LA levels in sweat during exercise and to investigate the relationship between the lactate threshold in sweat (sLT) and LT in blood (bLT) and the ventilatory threshold (VT). Methods: Twenty-three healthy subjects (age: median; 20 [interquartile range; 20, 21] years old) and 22 consecutive patients (age: 65 [57, 73] years old) with cardiovascular diseases (CVDs) underwent exercise tests with a RAMP protocol ergometer, simultaneously monitoring changes in the LA values in sweat using a wearable lactate sensor. The sLT was identified as the first significant increase in LA above baseline based on the graphical plots and change finder scores calculated by the Change Finder algorithm using the time-series data of the LA values during exercise. We applied the Bland-Altman method to verify similarities for each threshold. Results: During exercise, the dynamic changes in LA values in sweat were successfully visualized in real-time with a sharp continuous increase up to volitional exhaustion and a gradual decrease in the recovery period. In healthy subjects, the work rate (WR) at the sLT (WR-sLT) was substantially correlated with the WR at the bLT (r=0.90). The Bland-Altman plot described a strong agreement (the mean difference: -3.0 watt). Among 22 patients, there were 8 patients whose LA values in sweat were not measured due to a non-response in the sensor. In the remaining 13 cases, except for a patient in whom the VT could not be detected, the sLT was well correlated with bLT and VT (r=0.81 and 0.65, respectively); the mean differences were -8.3 and 3.4, and there was no bias between the mean values. Finally, the logistic regression analysis revealed that a non-response in the sensor was associated with NYHA 3/4 and low peak VO2 (Odds ratio [OR] 0.01 [95% confidence interval (CI); 0.00-0.13], OR 1.45 [95% CI; 1.09-2.20], respectively) Conclusions: Our wearable device enabled a continuous and real-time LA measurement in sweat during incremental exercise in a subset of patients with CVDs as well as healthy subjects. This can provide additional information for detecting the VT.

Which common NIRS variable reflects muscle estimated lactate threshold most closely?

2006 ◽  
Vol 31 (5) ◽  
pp. 612-620 ◽  
Author(s):  
Lixin Wang ◽  
Takahiro Yoshikawa ◽  
Taketaka Hara ◽  
Hayato Nakao ◽  
Takashi Suzuki ◽  
...  
Keyword(s):  
Lactate Threshold ◽  
Near Infrared ◽  
Ventilatory Threshold ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Oxygenation Index ◽  
Muscle Lactate ◽  
Tissue Oxygenation Index ◽  
The Mean ◽  
Tissue Hemoglobin

Various near-infrared spectroscopy (NIRS) variables have been used to estimate muscle lactate threshold (LT), but no study has determined which common NIRS variable best reflects muscle estimated LT. Establishing the inflection point of 2 regression lines for deoxyhaemoglobin (ΔHHbi.p.), oxyhaemoglobin (ΔO2Hbi.p.), and tissue oxygenation index (TOIi.p.), as well as for blood lactate concentration, we then investigated the relationships between NIRS variables and ventilatory threshold (VT), LT, or maximal tissue hemoglobin index (nTHImax) during incremental cycling exercise. ΔHHbi.p. and TOIi.p. could be determined for all 15 subjects, but ΔO2Hbi.p. was determined for only 11 subjects. The mean absolute values for the 2 measurable slopes of the 2 continuous linear regression lines exhibited increased changes in 3 NIRS variables. The workload and VO2 at ΔO2Hbi.p. and nTHImax were greater than those at VT, LT, ΔHHbi.p., and TOIi.p.. For workload and VO2, ΔHHbi.p. was correlated with VT and LT, whereas ΔO2Hbi.p. was correlated with nTHImax, and TOIi.p. with VT and nTHImax. These findings indicate that ΔO2Hb strongly corresponds with local perfusion, and TOI corresponds with both local perfusion and deoxygenation, but that ΔHHb can exactly determine deoxygenation changes and reflect O2 metabolic dynamics. The finding of strongest correlations between ΔHHb and VT or LT indicates that ΔHHb is the best variable for muscle LT estimation.

scholarly journals Validating Physiological and Biomechanical Parameters during Continuous Swimming at Speed Corresponding to Lactate Threshold

Proceedings ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 4
Author(s):  
Gavriil G. Arsoniadis ◽  
Ioannis S. Nikitakis ◽  
Petros G. Botonis ◽  
Ioannis Malliaros ◽  
Argyris G. Toubekis
Keyword(s):  
Lactate Threshold ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Maximum Speed ◽  
Front Crawl ◽  
Stroke Length ◽  
Mean Values ◽  
Speed Test ◽  
Biomechanical Parameters ◽  
The Individual

AIM: The purpose of this study was to validate the physiological responses and biomechanical parameters during continuous swimming at intensity corresponding to lactate threshold previously calculated by an intermittent, progressively increasing speed test (7 × 200-m). MATERIAL & METHOD: Nine competitive male and female swimmers (age, 19.2 ± 2.3 years; height, 175.3 ± 7.5 cm; body mass, 67.6 ± 8.7 kg; VO2max, 46.5 ± 15.6 mL/kg/min) performed a 7 × 200-m front crawl test reaching maximum speed in the last effort. Blood lactate concentration (BL) and oxygen uptake (VO2) were determined after each repetition, while heart rate (HR) was recorded continuously. Stroke rate (SR) and stroke length (SL) were measured in each 200-m effort. The speed at lactate threshold (sLT) was calculated using the individual speed vs. BL, and subsequently BL, VO2, HR, SR, and SL corresponding to sLT were calculated (BL-sLT, VO2-sLT, HR-sLT, SR-sLT, and SL-sLT). On a subsequent day, swimmers performed 30-min continuous swimming (T30) with a constant speed corresponding to sLT. BL, V02, HR, SR, and SL (BL-T30, V02-T30, HR-T30, SR-T30, and SL-T30) were measured in the 10th and 30th minutes of the T30 test, and the mean values were used for the statistical analysis. RESULTS: The speed corresponding to sLT was not different from the speed at T30 (1.33 ± 0.08 vs. 1.32 ± 0.09 m/s, p > 0.05). There was no difference between tests in VO2 (VO2-sLT, 34.9 ± 13.3 vs. VO2-T30, 32.1 ± 11.4 ml/kg/min, p = 0.47). However, not all swimmers were able to complete T30 at sLT, and BL, HR, and SR were higher, while SL was lower at the end of T30 compared to sLT (BL-sLT, 3.47 ± 0.60 mmol/L vs. BL-T30, 5.28 ± 3.15 mmol/L, p = 0.05; HR-sLT, 163 ± 10 vs. HR-T30, 171 ± 11 b/min, p = 0.03; SR-sLT, 28.0 ± 4.0 vs. SR-T30, 33.8 ± 3.2 strokes/min, p < 0.001; SL-sLT, 2.6 ± 0.4 vs. SL-T30, 2.4 ± 0.3 m/cycles, p < 0.001). A Bland-and-Altman plot indicated agreement between 7 × 200 and T30 in BL (bias 1.8 ± 2.4 mmol/L), VO2 (bias −2.9 ± 11.4 ml/kg/min), HR (bias 10.3 ± 12 b/min), SR (bias 5.3 ± 3.4 strokes/min), and SL (bias −0.3 ± 0.2 m/cycle), but the range of physiological and biomechanical data variations was large. CONCLUSIONS: Continuous swimming at speed corresponding to lactate threshold may not show the same physiological and biomechanical responses as those predicted by a progressively increasing speed test of 7 × 200-m.

A Novel Approach for Lactate Threshold Assessment Based on Rating of Perceived Exertion

2013 ◽  
Vol 8 (3) ◽  
pp. 263-270 ◽  
Author(s):  
Nicolas Fabre ◽  
Laurent Mourot ◽  
Livio Zerbini ◽  
Barbara Pellegrini ◽  
Lorenzo Bortolan ◽  
...  
Keyword(s):  
Lactate Threshold ◽  
Perceived Exertion ◽  
Ventilatory Threshold ◽  
Lactate Concentration ◽  
Cycle Ergometer ◽  
Rating Of Perceived Exertion ◽  
Strongly Correlated ◽  
Incremental Test ◽  
Distance Method ◽  
Novel Approach

This study tested the hypothesis that the DMAX (for maximal distance) method could be applied to ratings of perceived exertion (RPE), to propose a novel method for individual detection of the lactate threshold (LT) using RPE alone during an incremental test to exhaustion. Twenty-one participants performed an incremental test on a cycle ergometer. At the end of each stage, lactate concentration was measured and the participants estimated RPE using the Borg CR100 scale. The intensity corresponding to the fixed lactate values of 2 or 4 mmol · L−1(2mM and 4mM), the ventilatory threshold (VT), the respiratory-compensation point (RCP), and the instant of equality of pulmonary gas exchange (RER=1.00) were determined. Lactate (DMAX La) and RPE (DMAX RPE) thresholds were determined using the DMAX method. Oxygen uptake (VO2), heart rate, and power output measured at DMAX RPE and at DMAX La were not statistically different. Bland-Altman plots showed small bias and good agreements when DMAX RPE was compared with the DMAX La and RER=1.00 methods (bias = −0.05% and −2% of VO2max, respectively). Conversely, VO2 from the DMAX RPE method was lower than VO2 at 4 mM and at RCP and was higher than VO2 at 2 mM and at VT. VO2 at DMAX RPE was strongly correlated with VO2 at DMAX La (r = .97), at RER=1.00 (r = .97), at 2 mM (r = .85), at 4 mM (r = .93), at VT (r = .95), and at RCP (r = .95). The combination of the DMAX method with the RPE responses permitted precise and individualized estimates of LT using the DMAX method.

ENDOCRINE CHANGES BEFORE AND AFTER THE MENARCHE

1973 ◽  
Vol 74 (4) ◽  
pp. 685-694 ◽  
Author(s):  
B.-A. Lamberg ◽  
R.-L. Kantero ◽  
P. Saarinen ◽  
O. Widholm
Keyword(s):  
Binding Proteins ◽  
Maturation Process ◽  
Hormone Binding ◽  
Maximal Level ◽  
Continuous Increase ◽  
Mean Values ◽  
Thyroxine Binding Globulin ◽  
Before And After ◽  
Free Thyroxine Index ◽  
Level 1

ABSTRACT In an endocrine survey of healthy girls aged 8 to 20 years before and after the menarche, the serum thyroxine (T4), uptake of triiodothyronine by Sephadex (T3U), and the binding capacities of thyroxine binding globulin (TBG) and pre-albumin (TBPA) were measured, and a free thyroxine index (FTI = T4 × T3U) was calculated. The subjects were grouped according to skeletal age (SA) until the menarche and after this in the post-menarcheal age (PMA), expressed in years. T4 and FTI increased concomitantly and reached peak values of 8.40 μg/100 ml and 8.40, respectively, at 2–3 years PMA. The corresponding mean values for post-menarcheal girls (7.74 μg/100 ml and 7.51) differed statistically significantly from the means before the menarche (7.03 μg/ 100 ml and 6.75). The TBG remained virtually unchanged during the whole period, whereas the TBPA showed a continuous increase and reached a maximal level 1–2 years after the menarche. The maturation process in girls in some way involves an increase in the total and free T4 level which is not dependent on hormone binding proteins.

Effect of induced metabolic acidosis on intracellular pH, buffer capacity and contraction force of human skeletal muscle

1985 ◽  
Vol 69 (5) ◽  
pp. 505-510 ◽  
Author(s):  
E. Hultman ◽  
S. Del Canale ◽  
H. Sjöholm
Keyword(s):  
Buffer Capacity ◽  
Recovery Period ◽  
Mean Values ◽  
Muscle Ph ◽  
Before And After ◽  
Ph Buffer ◽  
Total Capacity ◽  
Ph Decrease ◽  
Muscle Biopsies

1. Five volunteers were studied before and after oral administration of NH4Cl (0.3 g/kg body wt.) given in order to create a moderate acidosis. 2. The quadriceps femoris muscles were stimulated electrically for 75 s and muscle biopsies for determination of pH and metabolite content were taken before, at the end of contraction and after 10 min in the recovery period. 3. Muscle pH at rest (mean 7.04) was not significantly decreased after acidification despite an extracellular pH decrease of 0.15 unit. 4. After contraction muscle pH was significantly lower after NH4Cl. Mean values before and after acidification were 6.70 and 6.54 respectively. 5. The buffer capacity calculated as the total capacity of the muscle to buffer H+ produced during the isometric contraction before and after NH4Cl ingestion was reduced from 68.6 sl to 54.5 sl. 6. The force produced by contracting muscle was significantly lower at the end of the contraction period after NH4Cl ingestion, 44.6% of initial compared with 55.4% without NH4Cl.

scholarly journals Lactate, Heart Rate and Rating of Perceived Exertion Responses to Shorter and Longer Duration CrossFit® Training Sessions

2018 ◽  
Vol 3 (4) ◽  
pp. 60 ◽  
Author(s):  
Ramires Tibana ◽  
Nuno de Sousa ◽  
Jonato Prestes ◽  
Fabrício Voltarelli
Keyword(s):  
Heart Rate ◽  
Perceived Exertion ◽  
Recovery Period ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Cardiovascular Responses ◽  
Cardiovascular Fitness ◽  
Rating Of Perceived Exertion ◽  
Training Experience ◽  
Significant Difference

The aim of this study was to analyze blood lactate concentration (LAC), heart rate (HR), and rating perceived exertion (RPE) during and after shorter and longer duration CrossFit® sessions. Nine men (27.7 ± 3.2 years; 11.3 ± 4.6% body fat percentage and training experience: 41.1 ± 19.6 months) randomly performed two CrossFit® sessions (shorter: ~4 min and longer: 17 min) with a 7-day interval between them. The response of LAC and HR were measured pre, during, immediately after, and 10, 20, and 30 min after the sessions. RPE was measured pre and immediately after sessions. Lactate levels were higher during the recovery of the shorter session as compared with the longer session (shorter: 15.9 ± 2.2 mmol/L/min, longer: 12.6 ± 2.6 mmol/L/min; p = 0.019). There were no significant differences between protocols on HR during (shorter: 176 ± 6 bpm or 91 ± 4% HRmax, longer: 174 ± 3 bpm or 90 ± 3% HRmax, p = 0.387). The LAC was significantly higher throughout the recovery period for both training sessions as compared to pre-exercise. The RPE was increased immediately after both sessions as compared to pre-exercise, while there was no significant difference between them (shorter: 8.7 ± 0.9, longer: 9.6 ± 0.5; p = 0.360). These results demonstrated that both shorter and longer sessions induced elevated cardiovascular responses which met the recommendations for gains in cardiovascular fitness. In addition, both training sessions had a high metabolic and perceptual response, which may not be suitable if performed on consecutive days.

scholarly journals Comparison of oxygen uptake during and after the execution of resistance exercises and exercises performed on ergometers, matched for intensity

2016 ◽  
Vol 53 (1) ◽  
pp. 179-187 ◽  
Author(s):  
José Vilaça-Alves ◽  
Nuno Miguel Freitas ◽  
Francisco José Saavedra ◽  
Christopher B. Scott ◽  
Victor Machado dos Reis ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Ventilatory Threshold ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Lower Limbs ◽  
Lower Body ◽  
Load Intensity ◽  
Moment Effect ◽  
The Moment ◽  
The Individual

AbstractThe aim of this study was to compare the values of oxygen uptake (VO2) during and after strength training exercises (STe) and ergometer exercises (Ee), matched for intensity and exercise time. Eight men (24 ± 2.33 years) performed upper and lower body cycling Ee at the individual’s ventilatory threshold (VE/VCO2). The STe session included half squats and the bench press which were performed with a load at the individual blood lactate concentration of 4 mmol/l. Both sessions lasted 30 minutes, alternating 50 seconds of effort with a 10 second transition time between upper and lower body work. The averaged overall VO2 between sessions was significantly higher for Ee (24.96 ± 3.6 ml·kg·min-1) compared to STe (21.66 ± 1.77 ml·kg·min-1) (p = 0.035), but this difference was only seen for the first 20 minutes of exercise. Absolute VO2 values between sessions did not reveal differences. There were more statistically greater values in Ee compared to STe, regarding VO2 of lower limbs (25.44 ± 3.84 ml·kg·min-1 versus 21.83 ± 2·24 ml·kg·min-1; p = 0.038) and upper limbs (24.49 ± 3.84 ml·kg·min-1 versus 21.54 ± 1.77 ml·kg·min-1; p = 0.047). There were further significant differences regarding the moment effect (p<0.0001) of both STe and Ee sessions. With respect to the moment × session effect, only VO2 5 minutes into recovery showed significant differences (p = 0.017). In conclusion, although significant increases in VO2 were seen following Ee compared to STe, it appears that the load/intensity, and not the material/equipment used for the execution of an exercise, are variables that best influence oxygen uptake.

Acute anemia increases lactate production and decreases clearance during exercise

1989 ◽  
Vol 67 (2) ◽  
pp. 756-764 ◽  
Author(s):  
S. G. Gregg ◽  
R. S. Mazzeo ◽  
T. F. Budinger ◽  
G. A. Brooks
Keyword(s):  
Blood Glucose ◽  
Blood Lactate ◽  
Lactate Concentration ◽  
Lactate Production ◽  
Blood Lactate Concentration ◽  
Flow Distribution ◽  
Plasma Catecholamine ◽  
Metabolic Clearance ◽  
Sprague Dawley ◽  
Mean Values

We evaluated whether elevated blood lactate concentration during exercise in anemia is the result of elevated production or reduced clearance. Female Sprague-Dawley rats were made acutely anemic by exchange transfusion of plasma for whole blood. Hemoglobin and hematocrit were reduced 33%, to 8.6 +/- 0.4 mg/dl and 26.5 +/- 1.1%, respectively. Blood lactate kinetics were studied by primed continuous infusion of [U-14C]lactate. Blood flow distribution during rest and exercise was determined from injection of 153Gd- and 113Sn-labeled microspheres. Resting blood glucose (5.1 +/- 0.2 mM) and lactate (1.9 +/- 0.02 mM) concentrations were not different in anemic animals. However, during exercise blood glucose was lower in anemic animals (4.0 +/- 0.2 vs. 4.6 +/- 0.1 mM) and lactate was higher (6.1 +/- 0.4 vs. 2.3 +/- 0.5 mM). Blood lactate disposal rates (turnover measured with recyclable tracer, Ri) were not different at rest and averaged 136 +/- 5.8 mumol.kg-1.min-1. Ri was significantly elevated in both control (260.9 +/- 7.1 mumol.kg-1.min-1) and anemic animals (372.6 +/- 8.6) during exercise. Metabolic clearance rate (MCR = Ri/[lactate]) did not differ during rest (151 +/- 8.2 ml.kg-1.min-1); MCR was reduced more by exercise in anemic animals (64.3 +/- 3.8) than in controls (129.2 +/- 4.1). Plasma catecholamine levels were not different in resting rats, with pooled mean values of 0.45 +/- 0.1 and 0.48 +/- 0.1 ng/ml for epinephrine (E) and norepinephrine (NE), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Effects of Successive Annual Training on Aerobic Endurance Indices in Young Swimmers

2017 ◽  
Vol 10 (1) ◽  
pp. 214-221 ◽  
Author(s):  
Gavriil G. Arsoniadis ◽  
Petros G. Botonis ◽  
Ioannis S. Nikitakis ◽  
Dimitrios Kalokiris ◽  
Argyris G. Toubekis
Keyword(s):  
Lactate Threshold ◽  
Lactate Concentration ◽  
Front Crawl ◽  
Female Age ◽  
Time Points ◽  
Training Adaptations ◽  
Before And After ◽  
Preparation Period ◽  
The Individual

Background: The magnitude of long-term changes on aerobic endurance indices provides useful information for understanding any training-induced adaptation during maturation. Objective: The aim of the present study was to compare changes in different aerobic endurance indices within two successive training years. Methods: Eight swimmers, (five male, three female; age: 14.1±1.5, height: 163.8±9.9 cm, body mass: 55.8±10 kg) were tested at four time-points, before and after the 12-week specific preparation period, within two successive training years (at year-1: start-1, end-1, at year-2: start-2, end-2). In each time-point were timed in distances of 50, 200 and 400 m front crawl to calculate the critical speed (CS). Subsequently, performed 5x200 m front crawl progressively increasing intensity and the lactate concentration was determined after each repetition. Using the individual speed vs. lactate concentration curve, the speed corresponding to 4 mmol.L-1 concentration (V4) and the speed corresponding to lactate threshold (sLT) were calculated. Results: Aerobic endurance was increased from year-1 to year-2 (effect of time, p<0.05) and no difference was observed between V4, sLT and CS at all time-points of evaluation (p>0.05). In year-1, V4, sLT and CS were unchanged even after the 12-week period (p>0.05). During year-2 of training it was only V4 that was increased from start-2 to end-2 (p<0.05), whereas sLT and CS were unchanged at the same period (p>0.05). Conclusion: The aerobic endurance indices change similarly throughout a two-year training, independent of the maturation. Possibly, V4 is more sensitive to detect training adaptations during the specific preparation period in young swimmers.

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