We often mention lactic acid during exercise, and we all know that the production of lactic acid is harmful to the body. So what is the relationship between exercise and lactic acid?
Lactic acid (a compound present in sweat) is an important biomarker quantified during exercise. It occupies a very important position in functional systems and is a normal by-product in the human body. After strenuous exercise, people produce more in the blood. Lactic acid.
For example: lactate, which is produced during the breakdown of glucose in the absence of oxygen in tissues, is an important biomarker present in both blood and sweat, reflecting the intensity of physical activity and the oxygenation status of muscles.
During exercise, energy-requiring muscles quickly run out of oxygen and fall back on an alternate metabolic pathway to provide energy at the "cost" of accumulating lactate, which can cause pain and fatigue.
The lactate is then released into the bloodstream and partially eliminated through sweat, meaning wearable chemical sensors can measure the concentration of lactate in sweat to show exercise intensity or muscle condition in real time.
During training, the uncomfortable burning sensation in the muscles is not caused by lactic acid, but by hydrogen ions produced by the pH drop in the body. The fatigue of muscle strength is related to lactic acid, but the cause of discomfort and subsequent residual pain It's more related to acid in the blood, when muscle fatigue usually means acidosis or an increase in the accumulation of lactic acid in the blood.
Lactic acid is not the cause of fatigue, but it does correlate with training decline, so it can be thought of as part of a biochemical recycling to help with fatigue.
Recently, many researchers have been continuously researching the relationship between exercise and lactic acid and the application of lactic acid in sports training, and have achieved great results. functional status, etc.
With the further development of wearable sensors, the possibility of non-invasively implementing sweat lactate measurement and continuously tracking its evolution during exercise, in addition to traditional chemical colorimetry, seems close to us in terms of detecting lactate content.
Recently, ACS (American Chemical Society) published an article - Can Wearable Sweat Lactate Sensors Contribute to Sports Physiology? It's incomplete, but exercise physiologists are investigating whether the technology could improve athletic performance while preventing injuries.
The researchers said that the goal of lactate sensor technology is to monitor the lactic acid content in the human body in real time and connect it to the state of human exercise, so as to confirm in real time whether the force exerted by the athlete is too large or too small, and improve the training efficiency. At present, the goal is still far away. There is also a lack of understanding of the relationship between sweat and blood lactate and other biomarkers, as there is insufficient evidence for the relationship between athletic performance and lactate concentrations.
Lactic acid is a by-product measured by a sports scientist or coach to assess the level of athletic performance of an athlete during fitness testing, and real-time sweat lactate measurement, along with other biomarkers, allows training sessions to be thoroughly monitored and adjusted, which ensures that athletes do not Training too hard or too little, thereby providing the right training regimen that enables the athlete to perform better in the long term.
Temperature and pH often affect electrochemical readings of lactic acid, resulting in measurements that are much lower than expected, so the researchers developed a method that uses a specially designed polymer layer outside the sensor to separate lactic acid from sweat.
The polymer protects the reactive enzymes in the sensor from reacting with anything other than lactic acid and enables the sensor to read higher concentrations of lactic acid than is typically read by electrochemical sensors.
The researchers are currently using the technology for physical tests, where blood and sweat measurements correlate with athletic performance in athletes, and sweat samples are taken to validate the sensor's performance in the lab.
In a recent study, Tokyo University of Science and Technology developed a soft and non-irritating microfluidic sensor to measure the concentration of lactic acid in sweat in real time, a wearable device that will help during intense physical exercise or Monitor the state of your body during work.
The researchers employed a method called "electron-beam-induced graft polymerization," in which functional molecules are bound to carbon-based materials that can spontaneously bind enzymes.
The researchers made the material into a liquid ink that could be used to print electrodes. The final part was to use a flexible electrode sensor to make it compatible with screen printing, a lightweight process that can be scaled up. After completing the sensing mechanism, the researchers studied The personnel devised a suitable system to collect sweat and transmit it to sensors.
This is achieved by a micro-sweat collection system made of polydimethylsiloxane (PDMS) material, which includes multiple small inlets, an outlet, and a chamber for between the sensors, which can Direct contact with skin.
The detection of the sensor and its operating range for lactate concentrations have been determined to be suitable for studying the "lactate threshold," the point in time at which aerobic metabolism changes to anaerobic metabolism during exercise.
Real-time monitoring of physical phenomena is important for related applications such as human health and medical care, and monitoring lactate thresholds will help optimize the training of athletes and exercise routines for rehabilitating patients and the elderly, and control the progress of movement.
The researchers are already testing the implementation of the sensor in real-world scenarios, and advances in this research will help develop the field of wearable chemical sensors that help us better track bodily processes and stay healthy.
Many studies have shown that lactate testing can help us clarify and understand the principle of training, regulate and control training intensity, assess and predict training level, so lactate is often called "training ruler".
The sweat lactate sensor has been confirmed as a promising solution to overcome the typical shortcomings of most blood tests.
At present, with the continuous improvement of lactic acid testing methods and the trend of professional development of mass fitness training, lactic acid testing and evaluation will be more and more widely used in sports science.
Two flexible interdigital electrodes developed by a sensing company are based on PI and PET respectively. Using PI/PET to be flexible and stretchable, the electrodes can closely fit the human skin and are now widely used in wearable devices. Sensors such as sweat lactate sensing detection.
PI flexible interdigital electrode is an organic polymer film, which is not only resistant to hydrolysis, high temperature and corrosion, but also has good biocompatibility and beneficial insulation.
