Garmin Body Battery fails to fill when sick – why
Garmin watches, and other wearables have been reported to indicate early signs of illness. This leads to questions about whether fitness trackers can detect health changes or if users are overinterpreting the data. Garmin states that its devices are not medical tools and are not intended to diagnose or treat medical conditions. Those with health concerns are advised to seek professional guidance.
The Body Battery feature, powered by Firstbeat analytics, measures stress and recovery to track available energy levels. The autonomic nervous system (ANS) regulates these processes through two subsystems: the sympathetic nervous system, which prepares the body for activity, and the parasympathetic nervous system, which promotes rest and recovery. The ANS also influences heart rate and heart rate variability (HRV), providing insight into physiological states.
Source Garmin.com
HRV measures the variation in time between heartbeats, with lower HRV typically associated with stress and higher HRV linked to relaxation. While stress, including physical exertion, raises heart rate and lowers HRV, a well-balanced system shows a regular energy depletion and recovery cycle. Disruptions to this cycle, such as prolonged stress or insufficient rest, can affect Body Battery readings.
During illness, the body initiates an immune response, often triggering increased heart rate and sympathetic nervous system activity. HRV may decline gradually, though the extent and speed of these changes vary based on the severity of the illness. Early indicators of sickness, such as a rising heart rate, reduced Body Battery recovery, or increased stress levels, may accompany symptoms like fatigue, headaches, or a sore throat. Fever can further amplify these effects, as even a slight temperature increase can raise heart rate significantly.
Long-term stress can weaken the immune system and reduce the body’s ability to recover. Maintaining a balanced routine that includes exercise, rest, and healthy habits is essential for overall well-being. The Body Battery feature provides insights into daily energy levels, helping users make informed decisions about their activity and recovery.