What are cardio load and target load?

Your heart is a powerful muscle at the center of your health, and its health is responsible for helping to improve your fitness. Fitbit’s cardio load is a personalized score to help you understand how hard your heart works during physical activity. Use cardio load to check how hard you pushed and avoid under or over training empowering you to reach your fitness goals while prioritizing your cardio health. Your daily target load is based on your cardio load and readiness levels that’s designed to balance recovery with performance.

Important:

• The cardio load tile is available in the Fitbit mobile app when you pair a supported device to your account.
• Cardio load is available on-device in Google Pixel Watch 3.
• Cardio load requires Fitbit mobile app version 4.26 or higher.
• Cardio load doesn’t accumulate during swimming exercises because heart rate tracking is disabled.

Expand all Collapse all

What is cardio load and target load?

Cardio load measures the strain on your cardiovascular system during exercise and daily activities. It considers not only the duration but also the intensity of your efforts, recognizing that higher-intensity exercise places greater demands on your heart. You receive more cardio load for longer and/or more strenuous activity based on your heart rate.

 Your target load is a suggested cardio load range that you can use to guide your training. Aim to get enough cardio load so that it lands in the target load range each day. It takes into account your fitness level, recent activity, and how recovered your body is, as well as whether you are looking to maintain or improve your cardio fitness level. Think of it as a "sweet spot" for exercise.

How do I use cardio load and target load?

• Track Your Progress: Track your cardio load over time to monitor your progress toward your fitness goals.
• Optimize Your Training: Use cardio load to guide daily activity levels and intensity, ensuring you're working out at the right intensity to reach your goals, while balancing recovery.
• Balance your Training Load: Use your results to help you understand if you’re accumulating cardio load the right amount for the goal you’ve set for yourself (maintaining or improving cardio fitness).

Additional Tips

• Individualized Metric: Remember that cardio load is personalized to you, based on your heart rate during physical activity. This helps ensure your daily target load is challenging enough while still being achievable.
• Varied Activities: Cardio load can be accumulated through activities that increase your heart rate including running, cycling, swimming, walking, and any of the 40+ activities in Fitbit device.
• Consult with Professionals: If you have concerns about your heart health or training intensity, you should always consult with a healthcare professional or certified trainer.

How is cardio load and target load calculated?

Cardio load is based on the TRIMP (TRaining IMPulse) model, a well-established method for assessing your training load. This model takes into account your heart rate during activity, and factors like your age, resting heart rate, and sex.

Fitbit calculates your target load using several factors:

• Training Target: Your target load is tailored to the fitness target you have set in the Fitbit app to maintain or improve fitness. Selecting “maintain cardio fitness” adjusts your target cardio load to be in line with your average cardio load over the last 4 weeks. Selecting “improve cardio fitness” adjusts your target cardio load to be slightly more than your daily average over the last 4 weeks. 
• Recent activity: Fitbit compares the last week of cardio load with the last month (often called Acute to Chronic Workload Ratio or ACWR) to ensure your target load is appropriate for your current level of training. If you’ve had a lighter last few days of activity, your target load might be higher while if you’ve taken on more recently, it might be lower to help you maintain balance and prevent overtraining.
• Daily readiness: Daily readiness determines your target load by checking how well your body has recovered from previous workouts and the stressors of everyday life. If your readiness is low, you’ll receive a lower target load that guides you to balance rest and recovery. For more information on how daily readiness is calculated, go to What's my daily readiness score in the Fitbit app?

Target load needs time to calibrate to you and your activity. Your first target load score appears after 7 consecutive days and nights of wearing the watch.

What is the minimum and maximum cardio load I can achieve in a day?

You start every day with zero cardio load. As your heart rate increases to the light zone and beyond, you'll begin to accumulate cardio load. At midnight, your cardio load resets to zero. There is no practical maximum to the load you can accumulate each day.

The maximum load represented by the end of the cardio load arc in the Fitbit app or on your watch is personalized based on your highest days of cardio load from the past 28 days. As you reach new maximum cardio load levels, you’ll notice this adjust as a result.

How do I track my cardio load trends?

Fitbit app

1. From the Today tab , tap the Cardio load tile.
2. Switch between the tabs at the top of the page to check your load trends over the course of a day, week, month, or year.

Tip: In the day view, you can check your total cardio load, your target, and the breakdown of the activities that contributed to that day’s cardio load. Tap the arrows to navigate to a different day.

Google Pixel Watch

1. Open the Fitbit Today app.
2. Tap the cardio load card to check the details on your current cardio load, your target load, a breakdown of what activities have contributed to today’s cardio load, and a graph of your cardio load trend over the week.

Fitbit Today App	Fitbit Cardio Load Details	Tile

Tip: To check how much cardio load you accumulate during a workout, customize your workout views, choosing cardio load as one of the key metrics during a workout, or check out your workout summary afterward.

Who is Target Load best for?

Target Load is best for people who regularly train their cardiovascular system, ideally in a consistent pattern of days.

How do I meet my target load?

You can achieve your target load by performing physical activities that earn cardio load. These are any activities that raise your heart rate into or above the "light" intensity zone (a personalized zone based on your fitness level and other factors). The more intense your activity, the faster you accrue cardio load and the sooner you reach your target load. Remember that your target load is for the whole day, and not just for a dedicated workout.

• Daily Goal: Aim to accumulate enough cardio load throughout the day to fall within your target load at the end of the day.
• Visual Guide: The Today section in the Fitbit app and watch displays your daily progress toward your target load goal to help you stay on track.
• Adjustments: Your target load may change over time as your fitness improves or if your activity levels change.

What is my training status?

Fitbit measures how active you’ve been over the last 7 days in comparison to how active you've been in the last 4 weeks to determine your training status.

If you take on too much cardio load too quickly, you’re at risk of overtraining. When you're overtrained, your body is constantly fighting to recover. Instead of improving your endurance and stamina, overtraining can lower your cardiovascular performance. You might find it harder to maintain your usual pace or distance, and you might feel more easily fatigued.

Conversely, if you stop training for a period of time, you’re at risk of undertraining. While taking breaks is essential, long periods of inactivity can reverse the gains you've made in your cardiovascular fitness. Your heart and lungs become less efficient at delivering oxygen to your muscles. You'll notice that you tire more easily and can't sustain your previous levels of exercise intensity or duration.

The sweet spots between undertraining and overtraining are maintaining or improving. Maintaining means you’re getting a consistent amount of cardio load and you regularly reach your target range. Improving indicates you’re regularly reaching the top of your target range or slightly exceeding it, helping improve your fitness.

Your target load guides you to maintain or improve depending on what goal you choose when you onboard. To change your goal:

1. From the Today tab  in the Fitbit app, tap the Cardio load tile.
2. Tap Adjust my target under the Fitness target section.
3. Choose Improve cardio fitness or Maintain cardio fitness to select your goal.

Why is target load Important?

• Just-right Training: Your target load takes your current fitness level and recent activity patterns into account. Hitting your target load consistently can help you achieve your fitness goals safely and effectively.
• Injury Prevention: Staying within your target load range can help to prevent overtraining, reducing the risk of injuries and burnout.
• Motivation: Tracking your progress toward your target load can be a great motivator to keep you engaged and excited about your workouts.

Remember: Target load isn't a rigid rule, but a helpful guide based on your body. Listen to your body, prioritize rest when needed, and enjoy the journey to a healthier, fitter you.

Why are there sudden changes in my target load? 

One of the keys to successful training is balancing load and recovery. If you do much more activity one day, for example a big workout and other activities across the day, then your target load will reduce on the subsequent day or days to help your body to adapt and recover. This reduces the risk of overtraining.

Why does my target load seem way too low or too high?

General Considerations:

• Ensure you allow sufficient time for your watch calibration for each individual activity levels, establishing a baseline measurement.
• Certain medications affecting heart rate will influence cardio load and target load calculations.
• Infrequent or erratic training patterns can impede accurate target load calculation.

If the target load appears low:

• Check your recovery levels a lower level may require a target load adjustment.
• The actual daily cardio load, or the amount of stress placed on the cardiovascular system during physical activity, may be lower than an individual's perceived exertion. This discrepancy can arise from various factors, including individual fitness levels, exercise intensity, duration, and environmental conditions.

If the target load appears high:

• Target load is derived from your daily cardio loads accumulated over several days. Daily cardio load accrues throughout daily activities including running, cycling, swimming, walking, and any of the 40+ activities in Fitbit device, not solely during workouts. Thus, the target load encompasses the entire daily target, not a singular workout.
• Prioritize self-assessment. If readiness is high but you feel fatigued, listen to your body and take it break.
• This may indicate early stages of illness, not yet reflected in the readiness score, and may influence target load. Prioritize rest, taking breaks, and reducing the intensity of your workout.

List of supported devices

Cardio load is available in the Fitbit mobile app when you use one of the following devices:

Fitbit	Google Pixel Watch
Inspire 2 Inspire 3 Luxe Sense Sense 2 Versa 2 Versa 3 Versa 4 Charge 5 Charge 6	Pixel Watch 1 Pixel Watch 2 Pixel Watch 3

Set up cardio load

Fitbit app

From the Today tab in the Fitbit app, tap the Cardio load tile. Follow the instructions in the app to choose your goal and begin tracking cardio load.

Tip: Cardio load appears instantly and doesn't require time to calibrate.

[Optional] To set cardio load as your focus at the top of the Today tab:

1. From the Today tab in the Fitbit app, tap the pencil icon .
2. Under Set your focus, swipe through the options and select Build cardio fitness.
3. Tap Save.

Tip: Target load needs time to calibrate to you. Your first target load range appears after 7 consecutive days of accumulating cardio load and sleeping with your device. To get the most accurate target, wear your watch during the daytime, especially during periods of exercise. For best results wear continuously for 28 days.

Troubleshooting cardio load and target load

How do I delete cardio load data?

1. From the Today tab in the Fitbit app, tap the Cardio load tile.
2. Tap the menu icon   Manage data.
3. Tap Delete Data Cardio load.
4. Select the data range you want to delete.
5. Tap Delete.

Why is my target load low when my readiness is high?

Your target load guides you to maintain or improve your fitness based on your historic training data (your cardio load accumulated over the last 4 weeks). Training a little more than usual is good for improving fitness, but pushing yourself too hard relative to your 4 week baseline can result in overtraining, which puts excess strain on your body and heart and is counterproductive to your fitness goal. Even if your readiness is high, Fitbit may reduce your target for a day in order to keep you in the training status “sweet spot” (refer to What is my training status?).

Fitbit recommends using readiness and cardio load as tools to help your train smarter, but you should also listen to your body when choosing how much exercise to take on.

What happens if I go above my target cardio load?

Going above your target cardio load on any given day isn't a problem. As your body experiences fitness gains, you'll notice your target range increasing as a result. In fact, it’s a great way to push yourself to higher fitness gains. However, doing this too frequently can lead to overtraining. The goal is to balance out your training so that from a weekly and monthly perspective you’re maintaining a good balance to achieve your fitness target. To learn more about this, refer to What is my training status?

How can I add or remove the readiness and cardio load tile on my Pixel Watch 3?

You can add the combined readiness and cardio load tile to your Pixel Watch 3 by following these instructions:

1. From your watch face, swipe to any tile.
2. Long press on the tile to bring up the tile selector menu.
3. Tap the + icon to add a tile.
4. Scroll vertically to find the Readiness and Load tile and tap to select it.
5. Use the arrows to select where the tile should appear among the other tiles on your watch.
6. Press the crown to return to your watch face.

To remove the Readiness and Load tile from your Pixel Watch 3:

1. From your watch face, swipe left or right until you reach the Readiness and Load tile.
2. Long press on the tile to bring up the tile selector menu.
3. Swipe vertically from bottom to top to remove the tile.
4. Press the crown to return to your watch face.¹

_{¹Like all heart rate tracking technologies, accuracy is affected by physiology, location of device, and your movements and activity.}