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Strength Sessions

A Strength session is a dynamic visual and audio neurofeedback experience that uses Muse S Athena fNIRS sensors.

During your session, Muse measures the concentration of oxygenated blood in your prefrontal cortex. You’ll exert as much mental effort as possible and propel your owl to fly, all with the power of your mind! When your mental effort dips, your owl will slow down, cueing you to return to your exercise. When you're mental effort is strong, your owl will fly faster.

Learn more about Strength sessions and the data you get access to after you finish a session.

Starting a Strength session
During a Strength session
Tips for best accuracy
Understanding your session results

Starting a Strength session

Open the Muse app and connect your Muse S Athena by Bluetooth.
Tap the Train tab.
Tap the Strength button in the Biofeedback Soundscapes section of the Train tab.
Tap MindFlight to start the sensor signal check. Relax and allow the sensors to settle. It may take up to a minute to pass the check.
Once you pass the signal signal check, select the session length. Recommended: 5 minutes - shorter is better at first, as the mind becomes naturally fatigued.
Tap Next, to begin calibration. This is an important phase. During calibration, Muse is determining the baseline average blood oxygenation in your prefrontal cortex, to compare against the rise and fall of your blood flow while you make a mental effort during the session.
When calibration is complete, tap Start to begin.

During a Strength session

Muse S Athena fNIRS sensors detect blood flow oxygenation to your prefrontal cortex.

Focus on exerting as much mental effort as possible to propel an owl to fly toward the horizon.
The owl will fly faster as you concentrate and exert more mental effort.
Here are a few things you can try to increase your mental effort:

Count backwards from 300, reducing by 3 each time: 300, 297, 294, etc.
For a quick boost, count backwards from 100: 99, 98, etc.
Focus on a thought or feeling that feels important for you, and try to sustain and clarify it. An example could be gratitude for the special people in your life. Remember: we get better at what we practice, so practice what’s important to you.

Boost! When prompted, swipe up to give your owl a boost! This helps you stay engaged while exerting mental effort.

Tips for accuracy and performance

Just like starting out with physical fitness, starting your mental fitness Strength sessions can feel challenging. You may feel frustrated your owl isn’t moving as much as want or think it should. This is perfectly normal. You’re doing something new, and it takes time and practice to build the muscle of our mental fitness.

Here are a few tips you can use to set yourself up for success:

Before your Strength session, complete a 1-2 minute Visualize Your Brain Blood Flow session to give the sensors time to settle.
Begin your session in an environment with minimal distractions.
Sit upright in a comfortable position.
Avoid tilting your head forwards or backwards. This will effect blood flow, and will skew your results. The idea is to keep your head in a comfortable, consistent, upright position.

Understanding your session results

Your brain needs oxygen to function—just like muscles need oxygen during exercise. When you make a strong mental effort, your prefrontal cortex works harder and demands more oxygen. Blood carries oxygen and nutrients to fuel decision-making, focus, and problem-solving, so more oxygen flow means the better your cognitive endurance and sustained mental effort.

Mental Strength Score and Graph

You’ll receive a score out of 100. The score is the highest peak of oxygenation levels during your session.

Your score represents your ability to progressively increase your mental effort during your session by sustaining higher oxygenation levels. A higher score means you achieved a more sustained increase in oxygen supply (HbO) to the prefrontal cortex.

In other words, the higher your score, the more you were able to maintain a high mental effort for longer. This practice helps to build focus, cognitive stamina, and resilience under pressure.

Brain Oxygenation Graph

This graph shows how your brain directs energy during Strength sessions by tracking blood oxygen levels in the prefrontal cortex—the area responsible for focus and decision-making.

fNIRS sensors track changes in hemoglobin concentration, measured in micromolar units (μM). The increase and decrease plotted in your graph is in comparison to the baseline oxygenation levels measured during the calibration before your session.
HbO: oxygenated blood (red line): Increases when your brain is working harder, delivering more energy for sustained mental effort.
HbR: deoxygenated blood (blue line): Decreases as your brain efficiently uses oxygen to maintain focus and endurance.

When the red line rises and the blue line falls, it means your brain is successfully increasing effort and optimizing cognitive performance.

How does Muse S Athena determine the Strength session results?

The more you are able to sustain a high mental effort, the higher your Strength score.

fNIRS (functional near-infrared spectroscopy) sensors: uses light to measure brain activity by tracking blood flow in the prefrontal cortex.

The fNIRS sensor sends harmless infrared light into your skin.
Oxygenated and deoxygenated blood absorb and reflect light differently.
fNIRS measures these changes, showing how much oxygen your brain is using while you make your mental effort during the session.

Other Strength biofeedback stats and data

Another way to understand how your Strength session went is to look at your stats and other data from the Muse sensors.