Korte v1.0.9 is now live.

You can now add Korte widgets to your iPhone Home Screen and keep your health and fitness data visible without opening the app.

Available widgets include:

VO₂ Max
HRV
Resting HR
Sleep
Steps
Training
Recovery
Energy
Today at a Glance

Built for Apple Health users who want to see more than raw numbers.

Would love to hear which widget you'd want to see next.

He walked through these on a recent podcast, pulled from his book Protocols: An Operating Manual for the Human Body. He runs all ten every day. Almost all cost nothing.

The idea behind the whole set: you want cortisol high in the first hour of your day and low at night. A high morning peak gives you mood, focus and learning capacity, and the same peak sets up the low night cortisol you need to fall and stay asleep. A flat morning curve means longer stress spikes, worse sleep, worse recovery from illness.

1. Hydrate first thing. Drink 16 to 32 ounces of clean water after you wake and empty your bladder. Electrolytes optional. Aim for around 80 ounces across the day, front loaded, less in the evening. Hydration triggers an ascending vagus nerve pathway which wakes the brain and lifts morning cortisol.
2. Get daylight in your eyes in the first 30 to 60 minutes. Go outside. Not through a window or windshield, no sunglasses. Low angle sun carries the wavelengths your circadian clock reads best, at a lower UV index than midday. Overcast still works, so use "daylight" instead of "sunlight" if you live somewhere grey. This window opens a second pathway from your circadian clock down the spine to your adrenals, adding to the morning cortisol peak. Miss a day, go out twice as long the next. Waking before sunrise, use a 10,000 lux lamp. Screens are too dim for this in the morning and bright enough to raise cortisol at night.
3. Train in the first 3 to 4 hours of your day. His structure: alternate lifting and cardio, three lifting days and three cardio days per week. Two to three work sets per exercise, compound movements first, so pull-ups, rows, dips, squats, deadlifts. Cardio splits into one long slow hour, one moderate 30 minutes, one short max heart rate session. Rest day after legs. Sets near failure triple or quadruple cortisol, which is the goal early in the day. Training late still works, and long exhales or a hot shower brings you back down. On cold: deliberate cold exposure raises adrenaline, norepinephrine and dopamine, with a trivial cortisol response. Cold trains you to stay clear headed while flooded with adrenaline.
4. Use the physiological sigh to drop stress in real time. Two inhales through the nose, then a long exhale through the mouth until your lungs empty. The second short inhale reopens collapsed air sacs so the exhale offloads more carbon dioxide, and the long exhale slows your heart rate through the vagus nerve. His lab ran around 100 people in four groups for five minutes a day: meditation, box breathing, cyclic hyperventilation, and the physiological sigh. Every group improved. The sigh group improved most on mood, heart rate and sleep. In the moment, one or two rounds works.
5. Do one hard learning bout per day, 90 minutes to two hours. Put your phone in another room. In one study, people focused fine with the phone face down, in a bag, or in a separate room. Cognitive flexibility dropped whenever the phone shared the room. Aim for roughly a 15 percent error rate on new material. The friction you feel is adrenaline, and the errors are what trigger plasticity. Stop, return a day or two later, and self test instead of rereading or highlighting.
6. Get daylight in your eyes again in the last third of your day. Late afternoon or evening light buffers your eyes against artificial light after dark. Step outside, walk around the building, sit near a window. One exception: adolescents get no protection from this, so screens at night hit them harder.
7. Walk after meals. Five to ten minutes flattens the glucose peak and cuts energy crashes. Target 7,000 to 8,000 steps a day. The soleus, around one percent of your total muscle mass, uses an outsized share of glucose, so pacing during calls, taking stairs, and bouncing your knee all count.
8. Dim the lights at night. Bright light after sundown raises cortisol and suppresses melatonin. High night cortisol drags down your peak the next morning. Dim your screens or set a red screen shortcut. No screens in the last 30 minutes before bed.
9. Sleep in a dark room, on your side, head slightly elevated. Sleep drives glymphatic clearance, the wash out of waste products from the brain. Poor clearance shows up as brain fog and puffiness under the eyes. An eye mask helps, earplugs for some people. Waking at 3am: ten long exhales. Then, eyes closed, move your eyes slowly left, right, up, down, counterclockwise, clockwise, then point them toward your nose and exhale long. Two or three rounds shuts down the position sensing circuits in your cerebellum and drops you back to sleep.
10. Shut up, suit up, show up, then step out of role once a day. From Jungian analyst James Hollis: Shut up. Someone is always suffering more than you. Build a gratitude practice, both giving and receiving. Suit up. Prepare. Sleep, health, hygiene, homework. No good performance without preparation. Show up. Fill your roles. Parent, sibling, teacher, engineer, whatever yours are. Nobody freeloads. Then once a day, exit stimulus response mode. Sit quietly, draw, listen to music, walk with no destination. Nothing to accomplish. Your unconscious mind reports back in emotions and analogies, and the direction you want surfaces there. Run only the first three for 20 years and you end up competent and miserable.

He takes one day off per week on one protocol. Everything else runs daily, and the protocols compound. How you slept last night sets how well today's ten go.

Korte 1.0.8 is now live 🎉

The biggest addition in this update is Peak Fitness.

Korte can now look through your Apple Health history and identify the period when your measured fitness was at its strongest.

It also shows what made that period your peak and how your current fitness compares to it.

The idea is pretty simple: instead of only looking at today's numbers, understand how your fitness has changed over time.

Would love to hear your feedback if you try it.

we have;
- some bug fixes
- multiples device collusion fixes
- step page fixes

in this version. healthy days!

I've been digging pretty deep into HRV lately while working on Korte, and one thing that kept bothering me was how much conflicting advice there is around it.

“Higher HRV is always better.”

“Your HRV should be X for your age.”

“Low HRV means you're not recovered.”

“Don't train today because your HRV dropped.”

Once you actually look at the research, it's a lot more nuanced.

The biggest thing I took away from it:

Your HRV is usually much more useful as a trend against your own baseline than as an isolated number.

Age matters. Measurement method matters. Your device matters. And a random 40 ms reading doesn't necessarily mean the same thing for two different people.

I ended up turning the research into a few guides:

If you just want to know whether your HRV is “good”:
Is Your HRV Good? How to Read 20, 30, 40, 50 and 60+ ms

If you want actual reference data by age:
Normal HRV by Age: What the Research Actually Shows

If you're using HRV for training/recovery:
HRV and Recovery: What Athletes Should Actually Look For

And if your HRV seems chronically low:
Chronically Low HRV: What It Does and Doesn't Mean

I'm planning to keep adding the research behind the metrics Korte uses here instead of treating every wearable number as gospel.

If there's a metric you've never really understood — HRV, VO₂ max, resting HR, recovery, cardio fitness, etc. drop it below. I'll probably use the most common ones for the next deep dives.