School of Graduate Studies

School of Graduate Studies
School of Graduate Studies

Shifting Our Thinking On Shift Work - Meet Salman Ahmadi

MSc Public Health Sciences, Field of Study Epidemiology   

by Phil Gaudreau, June 2021

Salman Ahmadi

The front desk at a hotel. The cockpit of an 18-wheeler. The nurse’s station at the intensive care unit. What do they all have in common? Typically, they are staffed by shift workers.

While essential to our economy, working the night shift can increase the risk for heart disease. These irregular schedules disrupt the body’s circadian rhythm, which is commonly (though somewhat misleadingly) referred to as its “day-night cycle”.

While the sleep-wake cycle is perhaps the most widely recognized process under circadian control, the vast majority of biological processes are governed by the circadian system. When we deviate from a normal cycle, it can lead to a phenomenon known as circadian disruption which is believed to be central to many chronic diseases.

This disruption to the circadian rhythm can affect the worker’s metabolism, cellular regeneration, nutritional intake, behaviour, and homeostasis (the regulation of their temperature, fluid balance, and other key health indicators). Shift work is also associated with an increase in stress behaviours like smoking and poor dieting, which further impacts their heart health.

This is not a small problem. CAREX Canada, an organization that shares knowledge about Canadians' exposures to known and suspected carcinogens, estimates that 1.8 million Canadians are shift workers.

Salman Ahmadi, an MSc candidate in Public Health Sciences, Field of Study Epidemiology, wants to help shift workers manage their health risks.

“Our circadian rhythms are ingrained through evolution as part of our biology and are dictated by the 24-hour light-dark solar cycle,” says Ahmadi. “While you may be able to mentally or physically adapt to working night shift, in a sense you are fighting the natural rhythms of your body.”

Ahmadi’s research focuses on the health impact of shift work, specifically looking at cardiovascular disease. Heart disease is the leading cause of death worldwide and the second leading cause of death among both sexes in Canada. 

“Disrupting our intrinsic circadian rhythms has a more significant impact on our health then we would think,” says Ahmadi. “While achieving seven or eight hours of sleep is critical, just shifting away from our normal cycle has pretty substantial impacts on our cardiovascular health. But in the modern world, unfortunately, we can’t remove shift work from equation of how services are demanded.”

“Ultimately, it’s not about complete abstinence from shift work, it’s about the reduction of harm,” he adds. “Perhaps in the future, when the research is more robust, advocacy can be put forth for structural changes in how shift schedules are organized.”

Salman became interested in public health during his undergraduate studies. He liked the combination of statistics and biology in the context of human health.

During his search for masters programs, Ahmadi learned that Queen’s has renowned facilities and researchers that work in chronic illnesses.

“I love my department – it’s small, tight-knit, and has a lot of great course offerings,” says Ahmadi.  “Leaping into graduate school is daunting, so the encouragement of my supervisors, Joan Tranmer and Kristan Aronson, and the professors help me to overcome a lot of the challenges.”

Once his masters is complete, Ahmadi would love to step into a role in healthcare.

“Working in an environment where I can apply my knowledge, learn new skills, and work in collaboration with a team would be the most rewarding,” says Ahmadi.

To learn more about graduate studies within the Department of Public Health Science, please visit their website.