Running Tolerance

Running tolerance is a feature designed to help you build mileage while balancing the risk of injury with performance gains. The running tolerance glance on your watch displays your acute impact load for today, a mileage estimate for the current training week, and a chart of your running tolerance and impact load trends over several weeks.

Impact load (mile or kilometer): Your impact mile (equivalent) is the amount of mechanical load on the body generated by running 1 mile on even ground, at an easy pace (baseline). Impact load is estimated using factors such as running intensity, whether you’re running uphill or downhill, and running dynamics data. For example, if you run 5 hard miles with hills, your impact load could be 8, meaning that the actual strain was equivalent to running 8 baseline miles. Similarly, if you run 3 slow and easy miles, it could have an impact load of 2.5.

Acute impact load: Acute impact load is a helpful indicator in the capacity you have to run that day, in the context of your weekly running tolerance. The impact load of each new run you record is added directly to your acute impact load, and the influence of that load diminishes gradually as time passes.

Weekly impact load: This value represents the unweighted sum impact of your runs for each training week. You can set the training week in your Garmin Connect settings. For the current training week, it displays how your “bucket” is filling throughout the week. It also provides the basis for the weekly historical view of impact load and running tolerance.

Tolerance: Tolerance reflects the maximum acute load your body can manage based on your running history. It is personalized, and it is adjusted at the beginning of each training week according to a science-based interpretation of your recent and long-term running history. For more information, go to Garmin.com/performance-data/running.

Understanding the results: Hard, fast running produces higher ground reaction forces and puts more wear and tear on your body than easy jogging. Walking segments during a run produce only half the impact of normal running. You can review a chart of the actual mileage plotted next to the impact load in your run activity history. A healthy approach to running will always involve listening to your body and using data together.