Q&A: Jason Jin on sleep, circadian health, and real energy

Jason Jin has spent the past decade studying how people sleep, wake, and move through their days. As a former sleep researcher and now founder of Zest, he’s focused on building tools rooted in circadian science. His work centers on one idea:modern life constantly pulls us out of sync with our biology, and it’s time to make alignment easier.

In this Q&A, he shares what he’s learned about real rest, the traps people fall into, and the simple habits that matter more than any gadget.

What have you learned about sleep since starting Zest?

Modern life is constantly pulling our sleep out of alignment. Bright screens push our bedtimes later, early alarms cut sleep short, and frequent or late eating disrupts the signals that keep our energy steady throughout the day.

“Our ancestors woke with the sun, moved throughout the day, ate earlier, and slept in darkness and cooler temperatures,” Jin says. Much of today’s fatigue is the downstream effect of fighting our own biology, and it’s what inspired him to build tools that counter that drift and reconnect with more natural energy cycles.

What do you think people misunderstand about feeling well-rested?

Jin has tested nearly every sleep hack and device on the market — first as a founder, and later while building Crescent’s massive dataset on what actually improves sleep. One pattern stood out: many people skip the basics and jump straight to expensive gadgets or supplements. “There’s a real power law in what actually drives better sleep,” he says. Most of the improvement comes from a small set of foundational habits.

His guidance is straightforward: get the fundamentals dialed in, like a good lifestyle routine, before trying to optimize.

What’s one habit that helps people wake up more alert?

“Expose your eyes to bright light within minutes of waking,” Jin says. That single habit does more to anchor your circadian clock and lift morning alertness than almost anything else.

He also recommends timing sleep in 90-minute increments — around 7.5 or 9 hours — to lower the chance of waking from a deep stage, which can make mornings feel jarring.

What do you wish more people understood about real rest or sustained energy?

“Your body is a highly adaptive, self-correcting system that adjusts sleep needs based on stress, illness, training load, emotional demands, and so many other lifestyle factors,” Jin says. He explains that sleep requirements aren’t fixed or one-size-fits-all — and that “there’s no biological free lunch.”

Almost every artificial spike in energy, alertness, or dopamine comes with a compensatory dip. The people who feel good consistently are the ones protecting stability and maintaining rhythms they can count on.