Do You Know Your “Biological Prime Time?”

Your most productive hours of the day are dependent on your DNA. Determining when you work best will improve your overall productivity.

February 29, 2016

Everyone has their own methods for increasing productivity. It’s a personal thing.

For example, I just listened to the same three songs on repeat while I wrote this article. To some of you, that makes me a crazy person. Others can probably relate.

But it turns out there is at least one universal way to determine how you work best, and that is by determining when you work best.

To do so, you must find your “biological prime time.”

What it is and how it helps increase productivity

The term biological prime time (BPT) was coined by Sam Carpenter in his 2011 book, Work the System: The Simple Mechanics of Making More and Working Less.

It is the time of day when you have the most energy and are, therefore, most productive.

Everyone’s is different.

Determining your BPT can be critical to success in the workplace by allowing you to dedicate your most productive hours to your most important tasks.

In addition, easier tasks like checking email can be left for your less productive hours.

And for all you coffee lovers out there, it can even help make those Starbucks runs more valuable.

Instead of guzzling down a large iced coffee during prime time (when you really don’t need it), drink one during sleepy time, instead, for a crucial energy boost.


How to determine your biological prime time

Like many things in life, there are two ways to go about this – the easy way and the hard way.

The easy way takes about 10 minutes, and while it’s a pretty lazy way of arriving at your answer, it gets the job done.

The hard way takes some time and requires more effort, but it could dramatically change your life.

The easy way

Since your BPT is based on your internal body clock, determining your “chronotype” – the scientific term for whether you’re a morning person or a night owl – can have many of the same positive effects on productivity.

The easiest way to determine your chronotype is to take the Horne-Ostberg questionnaire.

It’s a 10-minute survey and asks questions like when you’d go to sleep if you had no plans the following day, what time you prefer to hit the gym, and how you feel after waking up.

I took the survey and got “intermediate,” with an ideal bedtime of midnight. These results suggest that I should get to work slightly later than normal and dive into my most important tasks around mid-day.

While the “easy way” doesn’t provide you with your specific BPT, it does narrow it down. And even something as simple as taking mental notes of when you feel most alert within that time frame could help you narrow it down even further.

The hard way

If you’re really committed to learning about your internal body clock and becoming a more productive person, author Chris Bailey has you covered.

Chris wrote The Productivity Project, a book detailing the year he spent testing all kinds of productivity strategies.


In it, he chronicles the experiment he performed in order to determine his BPT, fully committing himself to observing his body’s natural energy levels without outside stimulants.

Note: While Chris spent three weeks on his experiment, this length of time isn’t mandatory. In fact, Chris says 21 days was a “personal preference” to guarantee accurate results. So, spending three days could still produce actionable results. It’s more about the intention.

Here’s what he did:

  • Cut all caffeine and alcohol from his diet
  • Ate as little sugar as possible
  • Woke up without an alarm each morning
  • Recorded his energy levels in a log every hour (see below)


By the end of the three weeks, he had determined his BPT was between 10 a.m. and noon, and between 5 p.m. and 8 p.m.

Armed with this information, Chris was able to restructure his daily routine moving forward so that he tackled his most important tasks during these times.

“The most productive people don’t just manage their time well, they also manage their energy and attention well,” Bailey said. “Rearranging your day around when you have the most energy is one simple way to work smarter instead of just harder.”

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Kendall BakerKendall Baker // The Hustle
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