What is Flow Index?

Flow Index is Lumia's read on your blood flow. A continuous, real-time number that reflects how much blood is moving through your arteries with every beat.

Think of it as a read on what your circulation is actually delivering in the moment. That your heart is beating is a given. Flow Index tells you how well it's moving blood through you right now.

Flow Index vs. Heart Rate: Heart rate tells you how fast your heart is going. Flow Index tells you how much each beat is delivering. A normal heart rate paired with a low Flow Index can mean your vessels are tight: your heart is working, but less is getting through. That gap is where the interesting information lives.

How Lumia reads it

Lumia reads your blood flow from your ear. Placement is the whole trick: the ear is one of the most accurate places on the body to pick up blood flow to your head, something that used to take specialized equipment in a clinic. Your earring takes readings throughout the day, so Flow Index is a continuous picture rather than a single snapshot.

Because it's always reading, you get a baseline that's truly yours, and you get to watch it move in real life, not just when you happen to be sitting in a doctor's office.

What your number means

There's no universal “good” Flow Index. It's a personal number, and it means the most when you read it against your own baseline over time. Like your temperature or your resting heart rate, what's normal for you is the reference that matters.

A higher Flow Index at rest usually means your system is relaxed and moving easily. A lower one now and then is normal and nothing to overthink. A lower one that stays down for several days is the kind of thing worth paying attention to, and worth mentioning to your doctor if it persists.

For most individuals, the Flow Index typical range is 60-80. Going about your normal day may have you in the 60s, while lying down can increase your Flow Index to the 90+ range. Extended periods of time below 50 can be concerning, especially if you are feeling light headed or fatigued. This is usually the result of overexertion. Lying down, drinking water, or taking a break can help.

What moves it, and what you can do

Your Flow Index shifts with the same everyday things that move blood flow generally. If you want to see yours trend in a good direction over time, the levers are the familiar ones:

• Sleep consistently: Rough nights show up fast; steady sleep tends to lift your morning number.

• Move regularly: Aerobic exercise builds stronger, more flexible vessels over time.

• Stay hydrated: Low water means lower blood volume and less efficient circulation.

• Go easy on alcohol: It shows up clearly in your overnight and morning readings.

• Manage stress: Ongoing stress keeps your vessels tight and your flow down.

• Stay warm: Cold constricts your vessels; comfort helps them stay open.

The real value is watching how each of these lands for you specifically. That feedback loop, seeing what a late night or a good week actually does to your number, is the point.

Flow Index is a wellness read, not a medical device or a diagnosis. It won't replace your doctor. What it gives you is a steady, personal look at one of your body's most basic systems.