Working Under Capacity: The Life Skill We Can’t Afford to Ignore

When I look back, I sometimes think about my toddler self in Hong Kong. The one whose nickname was “No Mackenzie Chan.”

Little Joan was bold and free. She said no easily, with no apology. She knew what she wanted and didn’t hesitate to set boundaries.

But that spirit didn’t last.

By the time my family moved to Canada, I was growing up in a household full of physicians, steeped in high achievement and high expectations, layered with the rules of a fundamentalist church. Everywhere I turned—at school, at home, at church—the message was the same: if you want to be valued, be a good girl.

So I became very good at being good.
Top marks. Every extracurricular. Following in my parents’ footsteps into medicine, a profession tailor-made for people-pleasers.

There’s a photo of me being hooded by my father at my medical school graduation. On the surface, it looks like the picture of success. What you can’t see is the anxiety thrumming underneath. For years, I measured my safety by how many people I could keep happy at once.

That worked .. until it didn’t.

Medicine Without a Curriculum

School had always provided a clear curriculum. Even medical training, with its contradictions, still came with structure and grades. But when I started practicing medicine as an independent attending, the ground shifted.

There were no more grades. No one standard of success. Instead, there were colleagues with differing opinions about what makes a “good doctor.” There were patients with even more conflicting ideas.

And I was trying to please them all.

At first, I doubled down on my old strategy: do more. Win awards. Join committees. Improve local healthcare systems. Outwardly, I was thriving. Inwardly, I was running on fumes.

I didn’t know how to do this job in a way that would make everyone happy. And the harder I tried, the more impossible it became.

The Pandemic Years

Then came COVID-19.

I gave birth to my second child in July 2020, masked in the delivery room. By early 2021, I was pumping milk between shifts as I stepped into the role of MD lead for our local vaccine clinic. That’s what you do when the world is on fire and you already have too much on your plate: you take on more.

For a while, it felt good. Thrilling, even. We were making a difference, all in it together. But as the months wore on and the sense of collective solidarity fractured, the overwhelm deepened.

My inbox was always overflowing. I’d see a patient and realize I hadn’t billed or finished charting their last visit. Meetings stacked on meetings. Efficiency hacks and productivity tricks could only carry me so far. The truth was simple: my plate was too full.

Breaking Points

By the winter of 2022, two things finally pushed me past my limit.

The first was professional. Viral illness spiked, as it does every year, but this time supply chain shortages meant we ran out of children’s Tylenol and antibiotics. Emergency rooms overflowed, and once again, the system’s answer was: “Family doctors, can you do more?”

I remember speaking on a provincial panel, being asked how we were fitting all the extra sick kids into our practices. I found myself thinking: This happens every year. Why is the only plan to stretch us thinner?

Other industries plan for seasonal surges. Walmart doesn’t ask the same static workforce to work triple hours through the holidays, they hire tens of thousands more staff. But in healthcare, there is no back bench. There is only us. And the message is always: do more.

The second breaking point was personal.

In early 2023, my husband was diagnosed with cancer. He is well now, after surgery and months of chemotherapy, but in that moment I had to face the absurdity of the system I was working in. If I got sick, or if someone I loved did, my patients would be orphaned. There was no backup, no surge capacity, no one to step in.

I realized I had to become more replaceable. I had to design my life and my practice so that stepping back didn’t equal collapse.

The Lesson I Couldn’t Ignore

Those crises revealed a truth I had been skirting for years: doing it all is literally impossible.

Not just practically, but mathematically. One study estimated that implementing all the clinical guidelines relevant to U.S. primary care would take 27.5 hours per day. Even Hermione’s time-turner couldn’t solve that one.

And yet, every time we do less, we feel guilty. Every time we do more than humanly possible, we still feel guilty for what’s left undone. That guilt reveals the depth of our conditioning: the belief that we should be able to do it all, even though the math doesn’t add up.

It’s time to let go of that illusion.

Because here’s the truth: anything we do is valuable. If you help one patient in a day, that is valuable. If you help ten, that is valuable. You are valuable, whether you care for patients or not, because your worth is not measured in output.

And if we want to survive in medicine and in life, we must learn to work under our capacity.

The 75% Rule

I began experimenting with what I call the 75% rule. I aim for my schedule to be about three-quarters full, leaving one-quarter intentionally open.

That white space is what allows me to handle the inevitable surprises—sick kids, urgent patient needs, personal crises—without collapsing. It’s what lets me eat dinner with my family every night, take a full lunch, and reserve time for music, nature, and therapy.

It’s what gives me the emotional bandwidth to meet my patients as humans, not burdens.

It’s what lets me think creatively about problems that cannot be solved by sheer endurance.

And it’s what makes me want to stay in medicine for the long haul.

The Stories We Tell Ourselves

Of course, this isn’t easy. Every time I talk about working under capacity, I hear the same objections.

• But what about the patients?
  We imagine we’re failing them if we work less. But honoring capacity is good patient care. A rested doctor makes fewer mistakes, listens more deeply, and stays in the profession longer.
  
  
• I can’t afford to work less.
  Overwork is expensive. It breeds billing errors, impulsive spending, and eventual medical leaves that cut income off entirely. Sustainable work is financially wiser than burnout.
  
  
• If I do less, the system will fall apart.
  But the system is already falling apart. Shouldering more only hides the cracks and ensures fewer people will want to follow us into this profession. By setting boundaries, we force leadership to see the true gap—and perhaps finally innovate.
  
  

These stories aren’t truths. They’re conditioning. And they keep us locked in cycles that harm us, our patients, and our system.

A Radical Act of Resistance

Choosing to work under capacity is not self-indulgence. It is resistance.

It is saying: I am not an infinite resource. My humanity matters. My care is precious, but it is not endless.

When we normalize working at 75%, we model a sustainable profession for the next generation. We create accurate data about what is truly possible. We invite creativity into spaces long held hostage by exhaustion.

And perhaps most importantly, we reclaim the child in us who once knew how to say no.

An Invitation

Healthcare does not need more martyrs. It needs more humans willing to stay human.

So here is the question I ask myself daily, and I invite you to ask yourself too:

If I take this on, can I still work under my maximum capacity?

If the answer is no, perhaps the most courageous act is to say no. Not because you don’t care enough. But because you care enough to stay.