Zone 2 refers to a moderate aerobic intensity, roughly the pace at which you can hold a conversation but would find it hard to sing, typically 60 to 70 percent of maximum heart rate. It trains the aerobic energy system and mitochondrial efficiency without the strain of high-intensity work.
A strong body of exercise physiology research links regular Zone 2 training to improved VO2 max, better fat metabolism and lower cardiovascular risk over time. It is a cornerstone of endurance training and increasingly discussed in longevity contexts because of its link to mitochondrial health.
Low risk for most healthy adults. The main pitfall is training too hard to actually stay in Zone 2 without a heart rate monitor, which changes the training effect.
Before starting a new cardio routine if you have known heart disease, uncontrolled blood pressure, or have been sedentary for a long period, particularly if over 40 or with other cardiovascular risk factors.
Free (walking, cycling, jogging). A heart rate monitor, optional, is a modest one-off cost.
Exercise physiology literature on aerobic base training and mitochondrial adaptation. ACSM exercise guidelines. Educational information only. Speak to a qualified healthcare professional before starting a new exercise programme.