Blood lactate, also known as lactic acid (not to be confused with lactating), is a molecule produced by the body as part of its energy production processes. Lactate used to be thought of as a waste product, however, new research has shown that it plays a crucial role in energy production, signaling, and metabolic regulation. It acts as a fuel source for muscles, including the heart, serves as a signaling molecule for adaptive responses to exercise, and contributes to the maintenance of metabolic homeostasis. Lactate plays several important roles in the body:

• Energy Production: Lactate is produced in the body at all times even when there is plenty of oxygen. It is produced in large quantities when the body needs to generate energy quickly, such as during high-intensity physical activities like sprinting or weightlifting. However, since it is continuously produced and utilized by the body, it is also used as a fuel during lower-intensity activities. Lactate provides a source of energy for muscle contractions and other physiological processes across all organs, not just muscles, highlighting its vital role in maintaining overall metabolic function.
• Fuel for Metabolism: Approximately 80% of lactate is metabolized in the body. The remainder is transported to the liver, where it is converted back into glucose (a process called gluconeogenesis). This glucose can then be stored or recirculated as an energy source.
• Energy Efficiency: Lactate can be used directly as a fuel source in most tissues, especially in the heart and slow-twitch muscle fibers. This can improve energy efficiency during endurance-related activities.
• Indicator of Metabolic Wellness and Fitness: The first lactate threshold is the lowest concentration at which lactate accumulates in the bloodstream faster than it can be cleared. By raising the lactate threshold through training, individuals can improve their metabolic efficiency, allowing sustainability of relatively higher intensities of physical activity for longer periods of time, which contributes to overall metabolic health and fitness.
• Monitoring and Training: Understanding the body's lactate response is valuable not only for training and performance optimization but also for overall health and wellness. Monitoring lactate levels during exercise can help athletes and coaches adjust training programs to improve performance and reduce the risk of over or undertraining. Additionally, maintaining efficient lactate metabolism can enhance cardiovascular health, support metabolic function, and contribute to improved management of chronic conditions such as diabetes and cardiovascular disease. By measuring and managing lactate levels, individuals can promote more effective training programs, improve recovery efficiency, reduce rates of fatigue, and support long-term metabolic health and wellness.
• Recovery and Fatigue: High levels of lactate can contribute to muscle fatigue and discomfort during intense exercise. Efficient management and clearance of lactate may reduce post-exercise muscle soreness, speed up recovery within and between bouts of training, and improve overall muscle metabolic health. This is particularly important for individuals with chronic conditions, such as cardiovascular disease or metabolic disorders, as better lactate management can enhance their physical capacity for daily activities and improve their overall physical well-being while living with a disease or condition.