Wearing your tracker too loosely or too tightly could lead to inaccurate or interrupted heart rate measurements, which will cause the test to abort. In this situation, you may receive the following error message: "Your tracker's heart rate detection is weak". The test requires a stable, consistent heart rate reading in order to calculate a VO2 submax score. You can ensure an accurate heart rate reading by:

  • Making sure your tracker is fitted correctly - tight enough to not move around the arm, but loose enough to not cause constriction of blood vessels or other discomfort.
  • Positioning the device correctly on your wrist - we recommend two finger breadths above the wrist bone as a general rule of thumb.
  • Preventing any obstructions (sunblock, clothing or moisture) from getting between the tracker and your skin.
  • If the test is performed under very cold conditions, blood flow to the extremities may be reduced significantly enough to prevent your tracker from taking accurate measures. If the test keeps failing, retry the test in warmer conditions, and take care to warm up enough to restore blood flow to your wrist.