# Flow Index

> What is Flow Index     Flow Index is a unitless number that reflects how well blood is flowing during times Lumia is actively tracking A higher Flow Index ind

Source: https://support.lumiahealth.com/en_us/flow-index-r1vGXYBaex

Last updated: 2026-09-04T20:49:15.940Z

**What is Flow Index?**

Flow Index tracks the total volume of blood flowing to your head. A higher Flow Index indicates more blood flow, and a lower Flow Index indicates less blood flow.

It’s important to know that the Flow Index does not have diagnostic value. It is not designed to diagnose, treat, cure, or prevent any medical condition. Instead, it’s a personal wellness tool to help you better understand and manage how you feel on a daily basis.

  

**How it is Calculated**

Flow Index is calculated based on how long your heart takes to squeeze blood out during each pump. The more you fill your heart with blood before it squeezes, the longer it will take to squeeze. A longer squeeze results in a higher Flow Index.

  

**Using Flow Index to Understand How You Feel**

Changes in blood flow are influenced by everyday factors like hydration, sleep, and posture, all of which can affect your mental clarity, energy, and recovery.

There is no universal “healthy” or “unhealthy” value. Your Flow Index is entirely relative to you. By logging events in the app to track your real-time Flow Index value alongside daily habits or stressors, you can spot your unique patterns over time. This makes it easy to connect how you feel with what your body is doing so you can make informed choices that support your daily performance and wellbeing.

  

**How Flow Index Compares to CBF**

Flow Index is not the same as Cerebral Blood Flow (CBF). For more information on the differences, see the [How It Works page](https://lumiahealth.com/pages/how-lumia-helps). You can also follow our latest research on the [Science page](https://lumiahealth.com/pages/science) to understand how Lumia Flow Index™ technology compares to CBF.