If it felt like everyone around you was sick at once this winter, you weren’t imagining it.
This year’s flu season peaked around mid-December, with a sharper, narrower curve than in previous years, according to Dr. Hugh Guan, associate medical officer of health at the Middlesex-London Health Unit, meaning more people were sick at the same time.
Ariana Bhatia, a third-year psychology and Ivey Business student, has noticed a pattern, contracting the flu this past month, as well as in December and October. Research suggests that stress may play a role.
“I’ve noticed that every time I have an exam, I get sick,” Bhatia recalls. “Even if it’s not an exam, just any sort of heavy academic stress usually ends up making me feel unwell. And I don’t think I’m the only one. We recently had a 24-hour report, and our entire group wasn’t feeling great.”
Guan points to the infectious disease triad used by infectious disease specialists: the agent, the host and the environment.
“The agent is the disease itself — in this case, the influenza virus. The host is the person, like you or me. And the environment is the broader context we live in,” says Guan. “All three influence how likely someone is to get sick and how severe that illness might be. Stress falls under the host’s response.”
Guan adds that stress is a well-documented factor in immune function.
“In immunology, we know that both internal and external factors can affect how well the immune system works. Stress counts as an external factor. For students, exam season is inherently stressful, and that stress can trigger changes in the immune system, increasing susceptibility to infectious diseases like influenza,” says Guan.
Wataru Inoue, an associate professor in the department of physiology and pharmacology at the Schulich School of Medicine & Dentistry, researches how the brain interprets and regulates stress.
“We still don’t fully understand the relationship between stress and immunity,” he explains. “But one well-documented mechanism is that stress elevates cortisol — a hormone that can suppress T-cell immune function. When that happens, our resistance to infectious disease decreases, making it easier for us to get sick.”
The solution, however, is not as simple as avoiding stress. Instead, Inoue says it requires recognizing that mental and physical health are deeply interconnected, and that stress should be treated with the same seriousness as any physical health risk.
Inoue recommends meditation as a medically supported strategy for stress reduction.
He also brings good news for sweet treat lovers.
“We’ve observed that things that make you feel good, like eating sweet foods, can suppress activity in brain areas involved in stress responses,” he says.
But, Inoue cautions that these effects are temporary.
“It may help manage stress in the moment, but it’s not a long-term solution,” he says. “Like many rewarding stimuli, repeated exposure can lead to desensitization, meaning it may stop working as effectively over time.”
Bhatia, a busy student, plans to implement yoga and mindfulness practices into her routine to support both her mental and physical health.
“I think we often neglect our mental health because we see it as just a barrier to productivity,” Bhatia says. “But during exam season, our brains are working overtime. The least we can do is give them a break once in a while.”