Why I still track my sleep after 2 years
It's not just because I'm a weirdo
Top of the morning, sapien. Welcome to Common Sense Medicine, where I try and keep you up to date on the latest and greatest in longevity science.
This week, I’m focusing more on tracking. I think that tracking has changed my life in many ways, but the most important way that it has helped me contextualize my life is through sleep tracking. I think that without the Apple watch tracking my sleep, it’s hard to devote enough time to sleep because there are so many interesting things to do, and they all come to a head right before I’m supposed to sleep. I’m reminded of my three goals — writing one blog / one video a week, trying new recipes, and starting to run. I’m trying to keep those in mind as I’m tracking and biasing towards action. With that, let’s talk about sleep tracking.
THE WEEKLY DOSE
How Sleep Tracking Changed My Life (and How to Make It Work for You)
If you clicked on this post or email, chances are you’re like me—a busy professional trying to get healthy while being pulled in a hundred different directions. You’re probably wondering whether a sleep tracker can genuinely help improve your rest or if it’s just another gadget that’ll end up stressing you out more.
Out of curiosity—and maybe a little desperation—I tracked my sleep every night for two years. What I learned was extraordinary. It didn’t just improve my sleep habits—it gave me a deeper understanding of my body, helped me build better routines, and ultimately changed my life.
But it didn’t start out that way. In fact, sleep tracking worsened my sleep at first. Here’s what happened—and what I wish I knew earlier.
The McNamara Fallacy: When Metrics Go Too Far
To understand how things went wrong, we need to talk about something called the McNamara Fallacy.
During the Vietnam War, U.S. Secretary of Defense Robert McNamara became obsessed with metrics. He tracked numbers like body counts and enemy supply lines to determine whether the war was going well. When a general warned him that rural Vietnamese people hated the U.S. presence—an insight that wasn’t easily quantifiable—McNamara scribbled it down… and then erased it. “If I can’t measure it,” he said, “it doesn’t matter.”
That’s the trap I fell into.
I started checking my Apple Watch in the middle of the night. I’d wake up at 2 a.m., roll over, and instead of falling back asleep, I’d think: Did that ruin my deep sleep score?
Tracking sleep became the very thing that ruined it.
Why I Still Track My Sleep
Despite that, I still track it. And I’m glad I do—because when used properly, it’s powerful.
Here’s what I’ve learned after two years:
Sleep Is Based on the Foundation of Consistency
When you’re busy, it’s easy to overlook sleep patterns. You feel tired, but you don’t know why. By reviewing my weekly sleep data, patterns started to emerge.
Before tracking, I didn’t realize how often I was sabotaging my own REM sleep. For example, I used to go to bed at 10 p.m. and wake up at 5 a.m.—but didn’t give myself enough time to wind down. That wrecked my ability to get into deep sleep and left me groggy.
Now, I give myself a solid hour to prep: laying out gym clothes, packing food, and doing a proper wind-down routine. That one adjustment—grounded in data—dramatically boosted my energy and mood.
A Better Environment Beats Better Tech
The turning point came when I started thinking less like a data analyst and more like Bryan Johnson, the entrepreneur famous for optimizing his sleep environment.
Bryan cools his bedroom to a precise 67–69°F, dims his lights, plays meditative music, and ensures his meals are done hours before bedtime. His goal? A perfect sleep score.
While I’m not spending millions like he is, I found some affordable upgrades that made a huge difference:
Blackout curtains or an eye mask – Most cost-effective way to ensure darkness.
Room cooling – Whether it’s adjusting the thermostat or using a fan, keeping things cool helps.
Noise reduction – A white noise machine or earplugs go a long way.
(Optional): Philips Hue red light routines – I haven’t pulled the trigger on this yet, but there’s evidence that red light exposure before bed improves melatonin production.
No tracker can fix a room that’s too hot, noisy, or bright. You have to fix that yourself.
Progress Over Perfection
One of the most important lessons? You’re allowed to be imperfect.
If you’re anxious or struggling with sleep, a tracker can show what’s kind of working—even if the numbers aren’t flawless. The goal isn’t to hit 100 every night. The goal is to feel better.
Are These Devices Even Accurate?
It’s a fair question.
The Apple Watch sleep algorithm, trained on over 1,400 nights of EEG and PSG data, showed:
97.9% sensitivity (correctly detecting sleep),
75% specificity (correctly detecting wakefulness).
There is also another figure showing four-stage classification performance of the Apple Watch, which I think is accurate enough for someone who’s looking for a consumer-grade sleep tracker.
In a 2020 study published in Sleep, researchers compared seven top consumer trackers (including Fitbit and Garmin) against gold-standard polysomnography.
The takeaway? Most devices did just as well—or better—than actigraphy, the previous mobile standard, for measuring sleep duration. Sleep stage accuracy was more mixed, but improving.
Final Thoughts: Is Sleep Tracking Worth It?
After two years of tracking my sleep, here’s my verdict: 100% yes—if you use it as a tool, not a crutch.
It helped me build a healthier routine, improve my workouts, avoid burnout, and feel genuinely better every day. And honestly? It’s one of the best decisions I’ve made for my health.
If you’re thinking about tracking your sleep, start simple. Use it to guide your habits—not define your self-worth. Progress, not perfection.
FIGURE OF THE WEEK
Q1(+2) 2025: Hypertrophy Cycle Progress
The upshot: The weight keeps going up!
Context: I guess it wasn’t a complete waste of time to go back on the tracking spree for my calories. I think that there is a point at which I’m going to call it done, but that point is not today. Great progress all around here. I am feeling a little heavier though, can’t wait to bring the weight back down during the running portion.
REMEMBER, IT’S JUST COMMON SENSE.
Thanks so much for reading! Let me know what you thought by replying to this email.
See you next week,
Shree (@shree_nadkarni)
The information provided here is not medical advice. This does not constitute a doctor patient relationship and this content is intended for entertainment, informational, and educational purposes only. Always consult with a doctor before starting new supplementation protocols.
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