The next phase of training is the Build Phase where you will build upon your aerobic engine you have just finished developing. Again, your “long runs” will be conducted in Zone 2 maybe 3 depending on your race distance. You will begin to decrease the amount of time spent in the aerobic training zone and increase the time in both lactate and anaerobic training zones. How much you increase is depended on the race distance. Short course will require a higher increase in anaerobic training zone and long course triathlete will increase more in the lactate training zone. This phase of training can last anywhere from 4-8 weeks.
The final phase is the taper leading into the race. This final phase can very greatly from athlete to athlete based on gender, race distance, age, experience, training base and training volume. As an example men typically need more time to recover than women. This time can be anywhere from 3 days to 3 weeks. The goal of this phase is to ensure the athlete is 100% recovered and at their peak on race day.
This article just covers the basics of training intensity and does not discuss recovery or nutrition, both of which play a role in your overall training. The higher the intensity and longer the training / race the longer the recovery and getting the appropriate nutrition after a workout will allow your body to recover quickly so you are prepared for the following days training event. It is key that you communicate with your coach and be honest with yourself when fatigue is setting in or training is too light.