Lactate Threshold and Ventilator Threshold
In recent years, lactate thresholds (LT) have emerged as an essential diagnostic tool for evaluating endurance performance (Albesa-Albiol et al., 2019). When determining the appropriate intensity levels for endurance athletes' workouts, the LT serves as an important reference point. According to Ghosh et al., significant physiological variables in endurance sports are the aerobic to anaerobic transition intensity. Monitoring Lactate Threshold Training is essential in determining athletic performance (2004). These concepts were incorporated into the 'aerobic-anaerobic transition.' This is a method for determining a person's ability to engage in long-term endurance activities.
Anaerobic threshold/lactate threshold AT is a term used to describe the point during exercise at which metabolic acidosis and the related alterations in gas exchange in the lungs begin to take place (Ghosh et al., 2004, p.25). The anaerobic threshold is the amount of effort between aerobic and anaerobic training. During the activity, there comes a time known as the AT when your body must make the transition from an aerobic to anaerobic metabolism. In endurance sports, the AT is a helpful measurement to utilize when choosing the intensity of activity for both training and competition (Ghosh et al., 2004). Concentrations of lactate in the blood increase with the intensity of physical activity. As Ghosh et al. point out, the anaerobic/lactate threshold was developed to identify the point at which metabolic acidosis occurs in response to physical activity (2004). To put it in perspective states Ghosh et al., the ventilatory anaerobic threshold (VT) is the sharp rise in ventilation during progressive exercise at a given intensity (2004). The VT can be utilized as a noninvasive predictor of LT. It is a measure of intensity that may be detected in a person's breathing at a point where lactate begins to build in the blood. The research by Plato et al. explains why LT should be used as a benchmark for determining training loads for endurance athletes. Athletes have utilized VT as a noninvasive measure of lactate threshold, although it underestimates training intensity for many of them (2008). In order to determine whether noninvasive maximum exercise testing data can be utilized to predict lactate threshold, this research compared invasive and noninvasive exercise testing data (Plato et al., 2008). The concept of LT was described by Ghosh et al., who observed that the production of lactate in the muscle rises in proportion to the volume of work being done or the percentage of VO2 max obtained (2004). On the other hand, as the activity intensity increases, the hydrogen ion generated from lactic acid can no longer be buffered by the blood bicarbonate reserves, leading to metabolic acidosis (Ghosh et al., 2004). Ghosh and his colleagues elaborate on endurance training in their study. When it comes to endurance athletes, the maximum amount of oxygen that their bodies can take in is determined by the capacity of their cardiovascular and respiratory systems to transport oxygen to the working muscles (2004). When there is a change in the supply of oxygen, there is a corresponding change in VO2 max. The rise in VO2 max that occurs as a consequence of training is primarily due to increased maximum cardiac output. When muscles become hyperperfused due to exercise, they have an exceptionally high capacity for oxygen consumption. The metabolic changes in skeletal muscle are, on the other hand, necessary to improve submaximal endurance performance. At a constant VO2, endurance training enhances performance by increasing the rate at which fat is burned and reducing the amount of lactic acid that builds up. VO2max is an essential parameter that determines the top limit of an individual's endurance performance (Gosh et al., 2004, p.30).
As a result, the LT comes before the VT because of oxygen availability. When tissue is hypoxic, it produces lactic acid, which impairs performance and leads to LT, the point at which metabolic acidosis occurs.
Physiological testing is useful not only for predicting performance, states Pallarés et al., but also for designing effective training programs, and endurance training for performance is more effective when workloads are prescribed individually (2016). Thus, blood lactate concentration fluctuations during a graded exercise test are frequently used to measure performance and prescribe training (GXT). Graded activity tests may include big muscle groups such as hip and leg musculature to correctly measure the requirement, supply, and consumption of oxygenated blood. According to some writers, the "lactate threshold" is the work rate at which blood lactate concentrations rise above the resting level (Pallarés et al., 2016). Pallarés et al. identified in their study by evaluating the lactate concentration-workload connection during the GXT as the maximum workload that was not related to an increase in lactate concentration above baseline (2016). One of the goals of this investigation was to see if the workload at ventilatory thresholds matched the blood lactate concentration threshold. Pallarés et al. discovered that workloads at the VT might be calculated by monitoring the workload at which lactate begins to rise above resting levels. In the case of VT, it is unclear whether the lactate threshold best reflects the condition (2016).
The most precise method for measuring this metabolic event is indirect calorimetry, and the VT has been demonstrated to measure endurance performance gains in athletes correctly (Pallarés et al., 2016, p.12).
Reference:
Albesa-Albiol, Lluis, et al. “Ventilatory Efficiency During Constant-Load Test at Lactate Threshold Intensity: Endurance Versus Resistance Exercises.” PloS One, vol. 14, no. 5, 2019, pp. e0216824–e0216824, https://doi.org/10.1371/journal.pone.0216824.
Faulhaber, Martin, et al. “Effects of Acute Hypoxia on Lactate Thresholds and High-Intensity Endurance Performance—A Pilot Study.” International Journal of Environmental Research and Public Health, vol. 18, no. 14, 2021, p. 7573–, https://doi.org/10.3390/ijerph18147573.
Ghosh AK. Anaerobic threshold: its concept and role in endurance sport. Malays J Med Sci. 2004 Jan;11(1):24-36. PMID: 22977357; PMCID: PMC3438148.
Pallarés JG, Morán-Navarro R, Ortega JF, Fernández-Elías VE, Mora-Rodriguez R. Validity and Reliability of Ventilatory and Blood Lactate Thresholds in Well-Trained Cyclists. PLoS One. 2016 Sep 22;11(9):e0163389. doi: 10.1371/journal.pone.0163389. PMID: 27657502; PMCID: PMC5033582.
Plato PA, McNulty M, Crunk SM, Tug Ergun A. Predicting lactate threshold using ventilatory threshold. Int J Sports Med. 2008 Sep;29(9):732-7. doi: 10.1055/s-2007-989453. Epub 2008 Jan 23. PMID: 18214811.
