Experts to Conduct Studies on The Effects of Shift-Works to Filipino Workers

Studies show evidences that shift-work or working on shift hours has implications to workers’ well-being or health.

According to the study conducted by the International Agency for Research on Cancer (IARC), working on shift hours may increase the risks of psychosomatic disorders of the gastrointestinal tract (colitis, gastroduodenitis, and peptic ulcer), cardiovascular disorders (hypertension, ischaemic heart diseases) and even cancer among shift-workers.

“This may be explained by the disruption of the circadian system that is caused by exposure to light at night that can alter sleep-activity patterns, suppress melatonin production, and deregulate genes involved in tumor development,” the IARC study further cited.

The human body is synchronized to a night and day pattern known as circadian or the body’s endogenous “biological” clock. This is a certain part of the brain that monitors the amount of light entering the body from time to time.

In the evening, when the light starts to wane, the body clock notices and prompts a flood of brain chemicals called melatonin, and signals the body to fall asleep. Overnight, melatonin levels remain high and drop at daybreak and remain low during the day.

At daytime, chemicals (neurotransmitters) such as noradrenaline and acetylcholine increase and keep the body awake. This system keeps the body synchronized affecting some body functions including temperature, digestion, heart rate and blood pressure.

Another study conducted by the School of Medicine and the Veterans Affair Healthcare System (SMVAHS) at the University of California has reported that continuous distracted sleeping pattern will lead to sleep deprivation that might adversely affect the brain and cognitive functions.

Shift-work is not a new concept among Filipinos,” said Professor Gayline F. Manalang of the Department of Environmental and Occupational Health, College of Public Health, University of the Philippines Manila during the 3rd PhilSHIFT colloquium held in UP Manila. “It is already been a practice in health care and manufacturing industries. However, this time, public awareness focuses on the call center industry or the business process outsourcing (BPO) industries in the Philippines because of the increasing number of individuals it employ, the encouragement the industry received from the government and its economic impact to the country.Given the alleged health related risks of shift-works to shift workers, this would be an aspect of interest begging for study.”

According to Professor Maria Eliza Ruiz Aguila from the College of Allied Medical Professions of UP Manila, “It is important to conduct a locally designed study to determine the chronotype of the Filipinos, that through research, we can devise strategies to take advantage of inter-individual variability on chronotype to improve the individual’s well being, performance and productivity without increasing the health risks.”

Professors Manalang and Aguila are both members of PhilSHIFT, a group of experts in the Philippines undergoing studies on the effects of shift-work to the health and wellness of shift-working Filipinos.

The PhilSHIFT is an interdisciplinary group that brings together the researchers from the College of Allied Medical Professions, College of Public Health and College of Medicine of the UP Manila and the Munich Institute of Medical Psychology of the Ludwig Maximillians University in Germany.

PhilSHIFT is currently populating a database on chronotypes of non-shift workers in the Philippines through an online survey using the Philippine Munich Chronotype Questionnaire ( This questionnaire is derived from the Munich Chronotype Questionnaire (MCTQ) and specifically tailored for Filipinos.

The information that will be gathered from the online survey will be the basis of the succeeding stages of the PhilSHIFT researches and will be used to investigate the characteristics of the circadian clock of shift workers in the Philippines.

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