What is the ventilatory threshold 1 (VT1)?

Ventilatory threshold 1 (VT1) is a key concept in exercise physiology, particularly when assessing aerobic fitness and training intensities. At VT1, the body begins to transition from primarily using fat as a fuel source to a greater reliance on carbohydrates. This shift occurs due to an increase in exercise intensity, requiring a more rapid energy supply that carbohydrates can provide more quickly than fat.

During aerobic exercise, the body can efficiently metabolize fat until a certain intensity is reached. When exercise intensity increases and surpasses a specific threshold, the body starts to produce lactate, which leads to an increased respiratory response to help eliminate this lactate through breathing. Thus, VT1 is marked by a noticeable change in breathing patterns that corresponds with the increase in carbohydrate metabolism. At this point, individuals might also start to feel that the exercise is becoming more challenging, reflecting their shift in energy expenditure.

Understanding VT1 is essential for personal trainers, as they can utilize this knowledge to help design effective training programs that optimize fat oxidation and improve cardiovascular fitness by keeping clients within appropriate intensity levels.