What types of training can improve aerobic exercise performance?

Low-intensity, high-volume training (<80% of maximal heart rate), threshold/tempo training (80–95% of maximal heart rate), and high-intensity interval training (HIIT) (>95% of maximal heart rate) can all improve aerobic exercise performance when performed 20–60 minutes per day, 3–5 times per week, for around 2–6 months.^[1] A well-designed training program may incorporate all types of training to attain peak performance, with some data suggesting a ratio of 80% low-intensity training and 20% high-intensity training is optimal.