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 The Effect of Electroacupuncture with Different Frequencies on Muscle Oxygenation in Humans

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Kenichi Kimura ◽  
Takayoshi Ryujin ◽  
Makoto Uno ◽  
Ikuro Wakayama
Keyword(s):  
Blood Pressure ◽  
Near Infrared ◽  
Tissue Oxygenation ◽  
Recovery Period ◽  
Oxygenation Index ◽  
Muscle Oxygenation ◽  
Healthy Male ◽  
Baseline Recording ◽  
Tissue Oxygenation Index ◽  
Tissue Hemoglobin

The aim of the present study was to investigate the effect of electroacupuncture (EA) with different frequencies on muscle oxygenation in humans. The subjects were 8 healthy male volunteers. Muscle oxygenation was measured using near-infrared spectroscopy (NIRS). Blood pressure (BP) and heart rate (HR) were monitored simultaneously. After baseline recording, EA was given for 15 min and recovery was measured for 20 minutes. The procedure of EA at 1 Hz, at 20 Hz, and at control followed in the same subjects. Tissue oxygenation index (TOI) decreased during EA at 20 Hz (P<0.05) and increased during the recovery period. Normalized tissue hemoglobin index (nTHI) also decreased during EA at 20 Hz and increased during the recovery period (P<0.05), whereas TOI and nTHI in the EA at 1 Hz did not change significantly throughout the experiment. The peak TOI and nTHI values at 20 Hz during the recovery period were higher than the values at 1 Hz and in the control (P<0.05). BP and HR remained constant. These data suggest that the supply of oxygen to muscle decreased during EA at 20 Hz and increased after EA at 20 Hz, without any changes in HR and BP.

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.

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.

Lactic acid infusion in dogs: effects of varying infusate pH

1983 ◽  
Vol 54 (5) ◽  
pp. 1254-1260 ◽  
Author(s):  
L. B. Gladden ◽  
J. W. Yates
Keyword(s):  
Lactic Acid ◽  
Blood Lactate ◽  
Muscle Blood Flow ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Weak Acid ◽  
Muscle Lactate ◽  
Acid Infusion ◽  
Arterial Blood ◽  
Arterial Ph

This study had two purposes: 1) to determine the effects of varying the pH of lactic acid infusion solutions on the acid-base status of anesthetized dogs, and 2) to determine the effect of elevated blood lactate concentration on muscle lactate concentration. The experiments were performed on the in situ gastro cnemius-plantaris muscle group in 14 mongrel dogs. The infusions increased the arterial blood lactate concentration to 11.0 +/- 0.5 (SE) mM after 20 min. Above an infusate pH of 4.4, the arterial pH increased by 0.118–0.167 during infusion; the arterial pH was unchanged when the infusate pH was between 3.4 and 4.0; and the arterial pH decreased as infusate pH decreased below 3.0. The effect of lactic acid infusion on blood pH appears to be the result of two opposing effects: 1) an acidifying effect due to its weak acid properties, and 2) an alkalinizing effect due to the metabolism of sodium lactate. The estimated ratio between intracellular muscle lactate and venous plasma water lactate averaged 0.647 +/- 0.038, indicative of a substantial gradient between blood and muscle. The infusion produced a significant change from lactate output to lactate uptake by the muscles. The infusion also transiently increased muscle blood flow and oxygen uptake.

Predicting Lactate Threshold With Rate of Perceived Exertion in Young Competitive Male Swimmers

2021 ◽  
pp. 003151252110052
Author(s):  
Jhonny K. F. da Silva ◽  
Bruna B. Sotomaior ◽  
Carolina F. Carneiro ◽  
Patrick Rodrigues ◽  
Lee Wharton ◽  
...  
Keyword(s):  
Lactate Threshold ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Test Protocol ◽  
Male Athletes ◽  
Rate Of Perceived Exertion ◽  
Significant Difference ◽  
Maximal Deviation ◽  
Competitive Swimmers

The purpose of this study was to verify the effectiveness of the rate of perceived exertion threshold (RPET) for predicting young competitive swimmers’ lactate threshold (LT) during incremental testing. We enrolled 13 male athletes ( M age = 16, SD = 0.6 years) in an incremental test protocol consisting of eight repetitions of a 100-meter crawl with 2-minute intervals between each repetition. We collected data for blood lactate concentration ([La]) and Borg scale rate of perceived exertion (RPE) at the end of each repetition. The results obtained were: M RPET = 4.98, SD = 1.12 arbitrary units (A.U.) and M lactate threshold = 4.24, SD = 1.12 mmol.L−1, with [La] and RPE identified by the maximal deviation (Dmax) method without a significant difference ( p > 0.05) and large correlations between DmaxLa and DmaxRPE at variables for time (r = 0.64), velocity (r = 0.67) and percentage of personal best time (PB) (r = 0.60). These results suggest that RPET is a good predictor of LT in young competitive swimmers.

Effect of Storage Techniques on Blood Lactate Concentration and Determination of Various Lactate Threshold Definitions

2006 ◽  
Vol 38 (Supplement) ◽  
pp. S514
Author(s):  
Matthew J. Garver ◽  
Leland J. Nielsen ◽  
Jared M. Dickinson ◽  
Derek S. Campbell ◽  
Charilaos Papadopoulos ◽  
...  
Keyword(s):  
Blood Lactate ◽  
Lactate Threshold ◽  
Lactate Concentration ◽  
Blood Lactate Concentration

Lactate Threshold in 50- to 55-Year-Old Men

1996 ◽  
Vol 4 (3) ◽  
pp. 286-296
Author(s):  
Fiona Iredale ◽  
Frank Bell ◽  
Myra Nimmo
Keyword(s):  
Blood Lactate ◽  
Lactate Threshold ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Peak Oxygen Uptake ◽  
State Test ◽  
The Absolute ◽  
Lactate Levels ◽  
Old Men ◽  
Treadmill Protocol

Fourteen sedentary 50- to 55-year-old men were exercised to exhaustion using an incremental treadmill protocol. Mean (±SEM) peak oxygen uptake (V̇O2peak) was 40.5 ± 1.19 ml · kg1· min−1, and maximum heart rate was 161 ± 4 beats · min−1. Blood lactate concentration was measured regularly to identify the lactate threshold (oxygen consumption at which blood lactate concentration begins to systematically increase). Threshold occurred at 84 ± 2% of V̇O2peak. The absolute lactate value at threshold was 2.9 ± 0.2 mmol · L−1. On a separate occasion, 6 subjects exercised continuously just below their individual lactate thresholds for 25 min without significantly raising their blood lactate levels from the 10th minute to the 25th. The absolute blood lactate level over the last 20 min of the steady-state test averaged 3.7 ± 1.2 mmol · L−1. This value is higher than that elicited at the threshold in the incremental test because of the differing nature of the protocols. It was concluded that although the lactate threshold occurs at a high percentage of V̇O2peak, subjects are still able to sustain exercise at that intensity for 25 min.

Relationship Between Running Velocity of 2 Distances and Various Lactate Parameters

2006 ◽  
Vol 1 (3) ◽  
pp. 270-283 ◽  
Author(s):  
Charilaos Papadopoulos ◽  
J. Andrew Doyle ◽  
Brian D. LaBudde
Keyword(s):  
Lactate Threshold ◽  
Lactate Concentration ◽  
Correlation Coefficients ◽  
Time Trial ◽  
Venous Catheter ◽  
Maximal Exercise Test ◽  
Straight Line ◽  
The Mean ◽  
The Relationship ◽  
Trained Runners

Purpose:The purpose of this study was to determine the relationship between various lactate-threshold (LT) definitions and the average running velocity during a 10-km and a 21.1-km time trial (TT).Methods:Thirteen well-trained runners completed an incremental maximal exercise test, a 10-km TT, and a 21.1-km TT on a motorized treadmill. Blood samples were collected through a venous catheter placed in an antecubital vein. Pearson's correlation coefficients were used to determine the relationship between the running velocity at the different LT definitions and the average running velocity during each TT. A dependent t test was used to determine statistical differences for the mean lactate response between the 2 running distances.Results:The LTDmax, the point on the regression curve that yielded the maximal perpendicular distance to the straight line formed by the 2 endpoints, was the LT definition with the highest correlation for both 10-km (r = .844) and 21.1-km TTs (r = .783). The velocity at the LTDmax was not, however, the velocity closest to the performance velocity for either distance. The mean running velocity at each LT was significantly different and tended to overestimate the mean TT performance velocities. The mean lactate concentration during the 10-km TT (3.52 ± 1.58 mmol) was significantly higher than during the 21.1-km TT (1.86 ± 0.90 mmol).Conclusion:These results indicate that a single LT point cannot be reliably associated with different running distances. Furthermore, these data suggest that a different methodology for estimating the LT that considers individual responses might be required for different running distances.

Effect of prior exercise on pulmonary O2 uptake and estimated muscle capillary blood flow kinetics during moderate-intensity field running in men

2009 ◽  
Vol 107 (2) ◽  
pp. 460-470 ◽  
Author(s):  
Martin Buchheit ◽  
Paul B. Laursen ◽  
Said Ahmaidi
Keyword(s):  
Blood Flow ◽  
Response Time ◽  
Near Infrared ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Capillary Blood ◽  
Capillary Blood Flow ◽  
Moderate Intensity ◽  
Prior Exercise ◽  
Intensity Field

The effect of prior exercise on pulmonary O2 uptake (V̇o2 p) and estimated muscle capillary blood flow (Q̇m) kinetics during moderate-intensity, field-based running was examined in 14 young adult men, presenting with either moderately fast (16 s < τV̇o2 p < 30 s; MFK) or very fast V̇o2 p kinetics (τV̇o2 p < 16 s; VFK) (i.e., primary time constant, τV̇o2 p). On four occasions, participants completed a square-wave protocol involving two bouts of running at 90–95% of estimated lactate threshold (Mod1 and Mod2), separated by 2 min of repeated supramaximal sprinting. V̇o2 p was measured breath by breath, heart rate (HR) beat to beat, and vastus lateralis oxygenation {deoxy-hemoglobin/myoglobin concentration (deoxy-[Hb+Mb])} using near-infrared spectroscopy. Mean response time of Q̇m (Q̇m MRT) was estimated by rearranging the Fick equation, using V̇o2 p and deoxy-[Hb+Mb] as proxies of muscle O2 uptake (V̇o2) and arteriovenous difference, respectively. HR, blood lactate concentration, total hemoglobin, and Q̇m were elevated before Mod2 compared with Mod1 (all P < 0.05). τV̇o2 p was shorter in VFK compared with MFK during Mod1 (13.1 ± 1.8 vs. 21.0 ± 2.5 s, P < 0.01), but not in Mod2 (12.9 ± 1.5 vs. 13.7 ± 3.8 s, P = 1.0). Q̇m MRT was shorter in VFK compared with MFK in Mod1 (8.8 ± 1.9 vs. 17.0 ± 3.4 s, P < 0.01), but not in Mod2 (10.1 ± 1.8 vs. 10.5 ± 3.5 s, P = 1.0). During Mod2, HR kinetics were slowed, whereas mean deoxy-[Hb+Mb] response time was unchanged. The difference in τV̇o2 p between Mod1 and Mod2 was related to Q̇m MRT measured at Mod1 ( r = 0.71, P < 0.01). Present results suggest that local O2 delivery (i.e., Q̇m) may be a factor contributing to the V̇o2 kinetic during the onset of moderate-intensity, field-based running exercise, at least in subjects exhibiting moderately fast V̇o2 kinetics.

scholarly journals Detection of the Lactate Threshold in Runners: What is the Ideal Speed to Start an Incremental Test?

2015 ◽  
Vol 45 (1) ◽  
pp. 217-224 ◽  
Author(s):  
José Luiz Dantas ◽  
Christian Doria
Keyword(s):  
Blood Lactate ◽  
Lactate Threshold ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Endurance Athletes ◽  
Incremental Test ◽  
Average Speed ◽  
Third Stage ◽  
The Relationship ◽  
The Ideal

Abstract Incremental tests on a treadmill are used to evaluate endurance athletes; however, no criterion exists to determine the intensity at which to start the test, potentially causing the loss of the first lactate threshold. This study aimed to determine the ideal speed for runners to start incremental treadmill tests. The study consisted of 94 runners who self-reported the average speed from their last competitive race (10-42.195 km) and performed an incremental test on a treadmill. The speeds used during the first three test stages were normalised in percentages of average competition speed and blood lactate concentration was analysed at the end of each stage. The relationship between speed in each stage and blood lactate concentration was analysed. In the first stage, at an intensity corresponding to 70% of the reported average race speed, only one volunteer had blood lactate concentration equal to 2 mmol·L-1, and in the third stage (90% of the average race speed) the majority of the volunteers had blood lactate concentration ≥2 mmol·L-1. Our results demonstrated that 70% of the average speed from the subject’s last competitive race - from 10 to 42.195 km - was the best option for obtaining blood lactate concentration <2 mmol·L-1 in the first stage, however, 80% of the average speed in marathons may be a possibility. Evaluators can use 70% of the average speed in competitive races as a strategy to ensure that the aerobic threshold intensity is not achieved during the first stage of incremental treadmill tests.

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