You’ve been exercising habitually for weeks, performing moderate exercise for 60 minutes five times per week. You feel good and want to move on to the next phase – aerobic efficiency training. This phase concentrates on increasing the time of cardiorespiratory exercise and adds intervals. This training improves aerobic efficiency, fitness, and health.
Aerobic efficiency training includes increased duration of sessions, increased frequency, and the introduction of interval training (increased intensity). The warm-up, cool-down, recovery intervals, and steady-state cardiorespiratory exercise are done at a level where you can talk but is starting to feel uncomfortable when you do (RPE=3-4 or moderate to somewhat hard). Intervals are added and they are performed at RPE=5 or hard. Intervals start short, usually around 60 seconds, with a 180 second recovery interval (1:3 ratio). This progresses to a ratio of 1:2 and eventually 1:1. This increase should occur over several weeks, but depends on your goals and fitness level. The exercise load should increase no more than 10% each week.
Many people do not progress beyond the aerobic-efficiency phase. They may train at this phase for years. As fitness levels increase, steady state exercise can progress to a RPE of 5, up from RPE of 3-4. Below is a sample aerobic efficiency training plan.
Once you are able to perform 50% of your cardiorespiratory training at this higher intensity, and reach seven or more hours of training per week, you can progress to the anaerobic-endurance training phase.