Cardio Load vs Strain

Bevel provides two different ways to understand how much effort your body is experiencing: Cardio Load and Strain. While they’re related, they measure very different things.

Understanding the distinction can help you interpret your data correctly and avoid confusion. For both Strain and Cardio Load to work properly, Bevel requires accurate heart data, including Resting Heart Rate (RHR) and correct Heart Rate Zones. RHR is typically derived from Sleep data, which requires wearing your device to bed.

If Cardio Load is missing, it’s often because sleep or RHR data isn’t available, or heart rate zones haven’t been set up. 

Cardio Load is based on the standard ATL (Acute Training Load) vs. CTL (Chronic Training Load) model, which is widely used across fitness apps and devices.

A key characteristic of this model is that it only includes logged workouts. If an activity isn’t recorded as a workout, it does not contribute to Cardio Load.

Because of this, Cardio Load represents a focused view of intentional training Stress. It’s best used to track how hard and how often you train over time.

Cardio Load Status shows how your recent cardiovascular training compares to your longer-term fitness trend. It helps you understand whether you’re maintaining, improving, or overreaching.

• Calibrating: Building your training profile. Keep training for more accurate insights. The algorithm is designed to show “Calibration” instead of displaying a potentially inaccurate status when it does not have enough stable data to work with. Cardio Load requires 6 weeks of data to provide accurate cardio fitness insights.

• Detraining: Losing progress. Time to scale up your cardio training.

• Maintaining: Training is steady and balanced.

• Peaking: Peak condition and well recovered. You’re in ideal race condition.

• Productive: Making strong cardio gains.

• Fatigured: Pushing but not recovering well.

• Overtraining: At risk of injury. It’s important to scale back your cardio training.

Note: Logging low-effort activities (like casual walks) as workouts can artificially inflate your Cardio Load. Even easy activities add “Training Stress” in this model and may push your acute load higher than intended, potentially showing overtraining when you’re not actually training hard.

Strain measures your total daily exertion.

In addition to movement and heart rate, Strain can also capture muscular load when you use Strength Builder. This allows Strain to reflect effort from strength training, even when heart rate alone may not fully represent the intensity.

Cardio Load, on the other hand, is based solely on heart rate data and is therefore best suited for cardio-focused activities. Strength workouts without sustained heart rate elevation may contribute little or no Cardio Load.

Unlike Cardio Load, Strain uses 24/7 movement data, which includes:

• Logged workouts

• Daily activities like walking, housework, and general movement

• Heart rate data throughout the day

This provides a big-picture view of how much effort your body expends throughout the entire day, not just during workouts.

Cardio Load is a longer term view of your training status. Strain is a daily metric you can track, and Target Strain will adjust daily depending on Strain history and current recovery.