Biological Prime Time


Biological Prime Time is about finding and winning your biological advantage to work with the highest level of focus and energy that you may have.

Biological Prime Time was coined by Sam Carpenter, an author, politician and business executive.

In his book Work the System, he refers to the rhythms in the human body called ultradian rhythms - the cycles of energy that vary in crests and troughs through the 24 hours.

The biological prime time is the time when you feel highly focused. This is also called the "golden hour."

Sam suggests using these high-energy periods to do the difficult tasks quickly and low energy intervals to do other simpler chores.

Why does it work?

  • Instills self-awareness
  • Aligns your natural high-energy time with working hours
  • Gets more things done quickly
  • Gives you periods of recovery in between high energy hours
  • Helps organize work by providing a natural schedule

How does Biological Prime Time work?

Identify Your Peak Hours

Every individual has their respective biological prime time.

A simple observation-led model can help one find their most productive periods.

  • Use time tracker tool or notebook
  • Tools like a time tracker can help you log and track the hours spent on a task and the time of the day you worked most.

    You can log your energy levels in a journal or a notebook and spend time on different tasks in a day.

  • Log in your energy levels
  • Log your energy levels during the day, ranking them upon a scale of 1 to 10.

  • Persist for 3 weeks
  • To find your ultradian rhythm keep logging your energy levels for at least 3 weeks to find a pattern

  • Stick to your routine
  • During these weeks, try to stick to your routine like going to bed, waking up, having lunch or dinner etc., at the same time to have comparable data.

  • Avoid depressants
  • While you are logging your energy levels, avoid anti-depressants, sleep stimulants, irregular nicotine intake to have your natural energy levels unaltered


Look at your data after three weeks and find out the peak hours of energy when you felt most active, energetic and fresh.


Maximize your high-energy hours by working smart and not indulging in small tasks that may waste this time.

  • Make a list of tasks beforehand
  • Keep your calendar free
  • Leave less important tasks for other hours of the day


John was starting up with his remote job and found it difficult to follow a 9 to 5 routine.

He could barely get out of bed till 11.00 am. Most of his time was spent in meetings, responding to emails and listing things he needed to do.

After 6:00 pm, he usually felt charged up and could continue his work till 12:00 pm.

It always made him feel better to work in the quietness of the night with more focus and no distractions around the house.

However, his colleagues always snubbed him to join meetings in the first half of the day when he was usually most sleepy.

Attending a productivity workshop, John identified that he might be a night owl biologically and not intentionally.

He started to log his energy levels during the 24 hours in his notebook. After 3 weeks, he opened his notebook and scanned through it.

John had ranked his energy levels during the day around 5 and 6, while after 6:00 pm, he had ranked his energy levels up to 9. Around 10:00 pm, when he usually felt wide awake, he had ranked this hour with an energy level 10 persistently for around 2 weeks or more in a 3-week schedule.

Now he was clear why he always felt his best at night. This was his biological prime time.

So, he moved his remote job's working hours later in the evening. In a few days, John observed that he could complete all his tasks before deadlines and ran ahead of his schedule.

His biological prime time was supporting him to work efficiently and achieve more.

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