Is it normal to have blood glucose spike during intense cardio?

Yes, it is normal to experience a spike in blood glucose levels during intense cardio exercises. This phenomenon is attributed to the body's response to the high demand for energy during activities like heavy lifting, sprinting, or high-intensity interval training (HIIT). During intense exercise, the body releases stress hormones such as catecholamines and cortisol. These hormones signal the liver to release glucose into the bloodstream to meet the increased energy demands of the muscles[1].

Additionally, the rise in glucose is a physiological response where the body uses stored glucose (glycogen) to supply energy. This is different from a glucose spike caused by food intake, as the glucose generated during exercise is immediately used by the body, making it a beneficial process. Glucose spikes from intense exercise are generally not harmful and can even improve insulin sensitivity over time[2].