Your body isn't keeping score
Finding out you have a second child on the way is exciting but slightly terrifying.
You think about all the things you endured to get the first one off the ground. How the hell do you juggle two?
In the first trimester, the hospital brought in a geneticist to tell us our daughter had an 85% chance of a birth defect. They mentioned the abortion option. It’s not one for us, so we spent months in a deep cope, figuring out how to meet the level of care we’d need to provide.
News like that has a way of laser-focusing your mind. You stop deferring the things that matter. You start thinking of ways to manage yourself and your time more efficiently.
In a stroke of luck, she landed on the 15% and came out completely fine, but my resolve didn’t change one bit.
I’d spent the four years since my first daughter was born reading everything I could about productivity — how to protect energy, how to build systems, how to stay sharp under pressure.
I’d landed on a conclusion that felt right: productivity is mostly about managing your energy. Your energy is a function of sleep, and the things that support sleep — fitness, nutrition, mental health.
Get that cycle right and you can handle a lot. Get it wrong and everything costs more than it should.
I was determined to get the fitness part right. To build something that worked inside a busy and chaotic life — not a perfect one. I figured the sleep and nutrition part would naturally follow along behind it.
The question was how. The world isn’t short on advice. But most of it didn’t feel like an answer. And then I came across a book called Younger Next Year, and one idea made the whole thing click.
The Two Signals That Actually Matter
At its core, the body responds to two primary signals.
Movement. And intensity of movement.
Movement tells your body it exists in an active environment. Intensity tells your body it needs to adapt to that environment.
That’s it. Everything else is downstream.
Movement is the baseline signal. Walking, carrying groceries, climbing stairs, gardening — these tell your body that physical capability is worth maintaining.
Intensity is different. Intensity is what happens when you push. When your breathing changes. When your legs burn. When you take the hill instead of the flat route, or walk faster than is comfortable, or pick up something heavy.
Movement keeps the lights on. Intensity upgrades the system.
Most fitness programs are just different ways of combining these two signals. The problem is that most people — without realizing it — are only sending one of them.
Younger Next Year describes the body as responding to activity in a surprisingly binary way. While the science is more nuanced than a light switch, modern research points in the same direction.
The body operates in different metabolic states depending on the signals it receives. The part of your brain that takes the signal is the primitive brain — the brainstem, sometimes called the reptile brain — the one that developed before the limbic and rational brains layered on top of it.
Watch an actual reptile in action and you’ll get a sense of how binary the primitive brain is. It’ll sit there basking in the sun when nothing’s happening. Soon as it sees something move, it scurries away. Nothing moving = off (sits there). Sees movement = on (flees).
That’s what your body is doing, but it’s taking in two signals for one flip of the switch. Consistent movement, and occasional intense movement.
When movement and intensity are present, it shifts your body toward adaptation. Mitochondria become more active. Metabolic flexibility improves. The body gets better at producing and using energy. Cardiovascular fitness improves. Strength improves. Recovery improves.
When those signals are absent, the opposite happens. The body adapts to inactivity just as readily as it adapts to activity. Lower mitochondrial function, reduced energy production, slower recovery — the system downgrades itself to match the demand being placed on it.
The body is constantly asking one question: Should I adapt for capability, or should I conserve?
Your behavior answers that question every day. Whether you mean it to or not.
Why You’re Not Getting Results — and It’s Not What You Think
When people aren’t seeing results, they usually blame the same three things.
Not enough time. Not consistent enough. Wrong program.
Sometimes those are true. But often the real issue is simpler: they never cross the threshold that tells the body to change.
This is where a lot of us fool ourselves.
A workout can feel productive without being demanding enough to drive adaptation. Exercise researchers have documented this gap between perceived exertion and actual exertion — people consistently think they’re working harder than they are. A walk feels brisk because you’re tired. A set feels hard because you haven’t exercised in a while. A workout feels intense because you showed up.
But the body doesn’t respond to your perception. It responds to the signal.
This is what I think of as the “almost working” zone. Not sedentary. Not training. Hovering in the middle — active enough to feel like you’re doing something, not demanding enough to trigger anything.
The research on high-intensity interval training is useful here.
Studies consistently show that short bursts of real effort produce greater improvements in cardiovascular fitness and metabolic health than longer, moderate workouts. The so-called “weekend warrior” studies are equally interesting: people who exercise intensely just once or twice a week achieve many of the same health benefits as those who work out daily.
The body isn’t counting days. It’s responding to signal strength.
You don’t necessarily need more time. You may simply need a stronger signal.
If you don’t send it, your master switch is set to hybernate. You are quite literally telling your body to slow down and store fat. Don’t do that.
The Simplest System You’ll Actually Do
This is where most fitness advice loses me. Everyone is searching for the optimal system. I think that’s the wrong question.
The better question: What’s the simplest system you’ll actually do?
The goal isn’t optimization. It’s sustainability.
A surprisingly effective approach looks like this: move every day, push yourself a few times a week, repeat for years. That’s not a fitness hack. It’s difficult mostly because it’s boring. But boring and consistent beats sophisticated and intermittent, every time.
Use variety strategically.
One of the more interesting threads in longevity research is the role of movement variety. There’s a moment in the Blue Zones research where something becomes obvious: the people living the longest aren’t “exercising.” They’re moving. But they’re not moving in straight lines.
In Sardinia and Ikaria, daily life involves hills, elevation changes, uneven terrain, constant variation in effort. Nobody is tracking heart rate zones. Nobody is chasing personal records. But their bodies are constantly receiving varied signals — sometimes easy, sometimes demanding, sometimes sustained, sometimes brief.
Modern life removes most of this variation. Flat floors, flat sidewalks, predictable environments, repetitive workouts. Same route. Same pace. Same resistance. Even consistent effort becomes a diminishing signal when the body adapts to it.
Japanese researchers formalized a version of this called interval walking: walk fast for three minutes, slow for three minutes, repeat. Simple. Studies show meaningful improvements in cardiovascular fitness, strength, blood pressure, and metabolic health. It’s essentially HIIT disguised as a walk.
The lesson: take the hill. Walk faster sometimes. Change your route. Vary the demand. The body responds remarkably well when the signal changes.
Build around habit, not motivation.
The best fitness program is rarely the most sophisticated — it’s the one that survives a busy week. Reduce friction. Reduce decisions. Make the barrier to entry as small as possible.
The fewer negotiations you have with yourself, the better.
Start with a daily walk. Track your steps. Upload your step counts to ChatGPT and it’ll congratulate the hell out of you.
Once you see a month’s worth of 8k+ daily steps, you’re halfway there. Then figure out how to get a 30-minute HITT workout once a week. Start by creating a YouTube playlist with as many of them as you can find so you don’t repeat the same intensity workout each week. Make that one weekly workout non-negotiable.
Eventually, doing the hard thing gets easier. You’ll start to look forward to your weekly workout and you’ll naturally work harder to protect it. Have faith. Remember, you’re stacking habits one at a time until you flip the master switch. From there, the benefits will compound.
Push voluntarily, occasionally.
There’s a benefit to intensity that doesn’t get enough attention: voluntary exertion changes your relationship with discomfort.
Every time you choose to walk a little faster, stay on the bike a little longer, take the extra hill — you’re practicing something deeper than fitness. You’re practicing effort. And that skill transfers. The ability to willingly do hard things is useful everywhere, not just in a workout.
The Benefits Are Bigger Than You Think
Most people start exercising for the visible stuff — lose weight, look better, improve a health marker. Those are legitimate goals.
But in my experience, the most valuable benefits show up somewhere else.
You have more energy. You sleep better. Your mood stabilizes. Stress becomes easier to manage. You become more resilient.
And your mind gets clearer.
That last one is strange until it happens to you. You don’t realize how much brain fog you’re carrying until it starts to lift. Focus sharpens. Decision-making improves. You feel more present. Productivity goes up in ways that have nothing to do with a productivity system.
In a world defined by information overload, algorithmic noise, and fragmented attention, that clarity has become more valuable than it’s ever been. Fitness isn’t just a health tool anymore. It’s a cognitive tool. A focus tool. A quality-of-life tool.
And ultimately, that’s why I think it matters — not because it helps you hit a number on a scale, but because it helps you show up better for your work, your family, and whatever you’re actually trying to build.
You don’t need a perfect plan.
You need a clear signal.
And once your body receives that signal, it starts working with you instead of against you.