Trusted by 300,000+ users
Train like a pro with Lumen

Many people train harder but stay stuck — stalled results, slow recovery, and low motivation. The problem? Guesswork. With Lumen as your AI fitness coach, just measure your breath to get your personalized fitness plan and transform plateaus into personal bests.

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How Lumen works

1

Planning to hit the gym? Take a breath

In 20 seconds, Lumen reveals what your 
body is burning for energy: carbs or fats.
2

Get your customized nutrition plan and macros

Receive your personalized nutrition plan daily, including tailored macros and carb recommendations, and track your meals with AI food logging to reach your goals, whether fitness performance or body recomposition.
3

Find out if you should fuel up or work out fasted

Based on your real-time results, the app lets you know if you should eat something to support your energy levels and avoid muscle breakdown
4

See real results at the gym

The more you use the app, the more insights
and strategies you’ll unlock to supercharge
your metabolic health and weight loss.

Real people. Real results.

See how Lumen works for some of our 300K+ users who cracked the code to sustainable weight loss.

How your metabolism works

Your daily lifestyle choices impact your metabolic health, 
and you can see it all in your breath. 

Digestion
When you consume food, it first enters the stomach, where digestive enzymes begin to break it down. The partially digested food then moves into the intestine, where it’s further broken down into nutrients, including glucose and fatty acids.
Metabolism
Mitochondria, the powerhouses of your cells, burn glucose and fat from the food you eat, or your body’s carb and fat stores, into energy you use daily. When your mitochondria and your metabolism are healthy, your body can make energy efficiently.
Breath
By measuring your breath, you can determine whether your mitochondria are burning glucose or fat for energy. This helps you understand your metabolism and the impact of your lifestyle choices on your fat burning and weight loss.
How Lumen measures your metabolism
The most advanced technology and sensors
Lumen uses ​​CO2 sensors, flow meters, barometric pressure, and temperature sensing technology to determine whether you’re burning carbs or fats for energy and sends this data to the app.
The Lumen app
The app then reveals what your body is burning for energy, and provides insights and strategies to help you reach your fitness goals.
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40+ integrations
Sync Lumen with your favorite health apps and wearables for a seamless, data-driven experience.

Benefits of using Lumen for fitness

Fuel smart to build your
muscles, hit your PRs, and
avoid muscle breakdown
Burn more fat, even at rest, to aid body recomp goals
Know when you can work out on an empty stomach
Train your body to use carbs efficiently for endurance and high-intensity training
Hit your macros daily with AI-powered meal plans tailored to your body
Recover better
with precise metabolic
insights post-workout
Finally understand your body and reach your fitness goals.
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Innovative research,
groundbreaking applications

Lumen’s accuracy is clinically validated, giving you the confidence to let go of generic fitness plans for good and trust your body’s own signals
FAQ

Lumen tailors your fitness plans based on real-time metabolic measurements through your breath. Your breath holds a lot of information, including whether you’re burning carbs or fat for energy. Based on your measurement result, which only takes 20 seconds, Lumen can coach you on how to fuel up before and after workouts and gauge your recovery post-workout. Lumen also trains you to improve your metabolic flexibility, which is how easily your body can shift between burning carbs and fats for fuel. This can help you supercharge your workouts, build and maintain muscle, burn more fat, reshape your body, and recover smarter.

Take a pre-workout breath measurement to determine if you should fuel up before your high-intensity workout. If you’re burning fat, that’s a sign your glycogen stores are low, and you should eat a fast-digesting carb source like a banana to avoid muscle breakdown.
Take a metabolic measurement again 30–45 minutes following your workout, after your heart rate has stabilized. This measurement gauges how intense your exercise was and how well your body is recovering.
During high-intensity workouts like sprinting or weightlifting, your mitochondria rely on carbs for a quick and powerful energy boost. Afterward, your body enters a recovery phase, replenishing glycogen stores and repairing muscle tissue. During this time, it burns mostly carbs.
Once you’ve shifted to fat burn, it means recovery is complete. A longer shift back to fat burn means you had an intense workout.

Choose your workout in the Lumen app, then take a pre-workout breath measurement. Depending on whether the workout is low- or high-intensity and your current fuel usage, Lumen will recommend whether you need to eat some carbs to avoid muscle breakdown.

A Lumen level 4 or 5 is recommended for strength training, as your body needs carbs for anaerobic training and to avoid muscle breakdown. A Lumen level 1 or 2 will help you tap into deeper fat burn for low-intensity cardio training like walking.

Yes, by inputting your desired workout in the Lumen app and measuring your metabolism before exercising, you can find out whether you can safely train fasted. For example, if you’re going to go on a Zone 2 walk and your breath measurement shows you’re mainly burning fats, then you can work out on an empty stomach. However, if you’re going to a HIIT session, you’d need to fuel up with carbs to avoid muscle breakdown.

Lumen automatically adjusts your macros when you input a workout session in the app.

You can connect to 50+ apps directly through the Lumen app.

Yes, you can use Lumen to optimize your pre- and post-workout fueling and recovery for HIIT, CrossFit, or triathlon training by measuring your metabolism before and after your chosen workout session.