Why does my heart rate stay elevated after zone 2 sessions, can someone explain the specific physiological mechanisms behind this phenomenon, particularly in relation to lactate threshold and aerobic capacity? Is it related to the accumulation of lactate in the muscles, or is there another factor at play, such as an increase in systemic vascular resistance or a delay in parasympathetic reactivation?
Ive noticed that after a 2-3 hour zone 2 ride, my heart rate takes significantly longer to return to normal, often taking 30-60 minutes to drop below 120bpm, even after a thorough cool-down and stretching routine. This has led me to wonder whether this is a normal adaptation to endurance training, or if its indicative of an underlying issue, such as inadequate aerobic conditioning or poor recovery strategies.
Some studies suggest that prolonged exposure to moderate-intensity exercise can lead to changes in cardiac function, including increased stroke volume and cardiac output, which can persist even after cessation of exercise. However, Im not convinced this fully explains the sustained elevation in heart rate observed after zone 2 sessions.
Can someone provide insight into the underlying mechanisms driving this phenomenon, and whether its something to be concerned about, or simply a benign adaptation to endurance training? Are there any practical implications for training and recovery strategies that can help mitigate or exploit this effect?