This example demonstrates calculating, tracking, and fulfilling the need to sleep.

Calculating my needs

As a 25-year-old, I need approximately 4–6 sleep cycles per night, which would require 7–9 hours of sleep per night. However, I also have recognized that I often will sleep for 9 hours on average, meaning I probably need 6 sleep cycles, considering my genetic disposition and my typical level of physical activeness throughout the day.

Tracking my needs

Using the objective measurements of sleep needs, I try to measure the number of sleep cycles that my body undergoes, based on the length of time I sleep at night.


Calculate the number of sleep cycles per each period of uninterrupted sleep.

  • I fell asleep at approximately 11:30 PM (23:30) and woke up at approximately 2:30 AM for an estimated total time of 180 minutes.

    • This period of sleep had 2 full sleep cycles.
  • I fell asleep again at about 3:00 AM and work up at 7:00 AM for a total time of approximately 240 minutes.

    • This period of sleep had 2 full sleep cycles and about ⅔ of a third sleep cycle.

Calculate the sum of sleep cycles.

  • In sum, I slept for 4 and ⅔ sleep cycles.

Fulfilling my needs

If I subtract my current sleep fulfillment for the day from my calculated daily needs, then I know that I have a sleep deficit of approximately 2 sleep cycles. Also, I had a particularly active day today, because I played a long game of soccer. Therefore, I should strive for a full 6 or even 7 sleep cycles tonight.

Setting goals

Given these factors, I need to decide when to go to sleep tonight, knowing that I will have to wake at 7 AM tomorrow morning. I need approximately 9–10½ hours of sleep for 6–7 sleep cycles. Because I often require 30 minutes to fully fall asleep, I will go to bed around 8–9 PM (20:00–21:00) tonight.

Building patterns and habits

Over the course of the week, I will strive to keep track of which nights were most restful and set that average bedtime as my stable sleep schedule.