How well do you know your biological clock?

Jee Y. Geronimo

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How well do you know your biological clock?
As we go on with our daily activities, we observe 3 clocks: the biological clock, the solar clock, and the social clock. Are Filipinos able to synchronize these clocks every day?

MANILA, Philippines – It’s no secret that some people are more productive in the morning, and some at night. The field of chronobiology is still exploring the whys and hows.

Here in the Philippines, where the Business Process Outsourcing (BPO) sector is booming, the general public is just as curious as scientists on how this clock works. 

In 2010, research group PhilSHIFT began a project that aims to study chronotypes of Filipinos. A chronotype refers to one’s internal timing and reflects how the biological clock fits into the 24-hour day.

As we go on with our daily activities, said PhilSHIFT collaborator Gayline Manalang Jr, we observe 3 clocks: the biological clock, the solar clock, and the social clock. These are clocks we try to synchronize every day. 

While we consider the experience of those who work or study during the day as “natural,” working into the night has also become more common, she told Rappler.

(Look for the Philippine flag)

“All these notions about working against your biological clock – for example, working at night in a call center – before you say it causes something abnormal, you have to have reference with those who don’t do night work,” said Manalang, who also teaches at the College of Public Health at the University of the Philippines (UP) Manila. (READ: In defense of telephone operators)

In the survey, Filipinos who are non-shift workers can get to know what biological clock type or chronotype they have, and their sleep debt. 

Sleep debt is a symptom of the discrepancy between one’s internal timing and external timing.

This discrepancy is what Munich Chronotype Questionnaire developer Till Roenneberg calls the “social jetlag” – when the biological clock is not in sync with the solar clock or the social clock, this could lead to “unnatural” behaviors and health issues.

Recent research has shown relationships between social jetlag and obesity, which makes us wonder at the chronotype of Filipinos, whether they have social jetlag, and how this affects their health,” Manalang told Rappler. (READ: Working in shifts? Your brain could suffer loss of memory, power)

Chronotypes among Filipinos

The Philippine Munich Chronotype Questionnaire – used in the ongoing survey – determines one’s mid-sleep time to assign a chronotype.

“Because the most common mid-sleep times have been shown to differ between populations, someone in Europe may have the same chronotype category with a Filipino but their population’s mid-sleep reference are different. Therefore, we would like to look at Philippine chronotypes,” Manalang explained. 

The Philippine questionnaire distinguishes 7 chronotypes:

  • Extreme early
  • Moderate early
  • Slight early
  • Normal 
  • Slight late 
  • Moderate late
  • Extreme late

Through the survey, the researchers want to know the most common chronotype among Filipinos. 

The role of light

But Manalang said that one’s chronotype changes with age, and this may be due to many factors, particularly environmental factors.

“The strongest factor that influences internal timing is how much sun exposure you get. Some other factors [include] your social schedule, your work schedule…the timing of your meals,” she said.

If you take the survey, you will get an evaluation of your chronotype and suggestions on how you can experiment with the effects of bright light in order to fall asleep earlier (if your biological clock puts you to bed too late) or later (if your biological clock puts you to bed too early).

While reseachers are still in the process of developing a questionnaire for Filipino shift workers, the database of chronotypes from the Philippine Chronotype and Social Jetlag survey can provide the chronotype profile of Filipinos in key call center cities (Metro Manila, Metro Cebu, Metro Clark, and Metro Davao).

This profile can be analyzed to help give advice to Filipinos about chronotypes, staying healthy, sleeping well, and being productive.

Manalang’s research team from UP Manila is collaborating with Roenneberg and colleagues at the Ludwig Maximilians University Munich for this project, which has been registered with the Philippine Health Research Registry since 2014.

The project is funded by the UP Center for Integrative and Development Studies and the Philippine Council for Health Research and Development. –

Office worker on computer image from Shutterstock

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Jee Y. Geronimo

Jee is part of Rappler's Central Desk, handling most of the world, science, and environment stories on the site. She enjoys listening to podcasts and K-pop, watching Asian dramas, and running long distances. She hopes to visit Israel someday to retrace the steps of her Savior.