In a fairly typical “conflict” situation there is not much recovery in
the stress and recovery chart (i.e. stress state is present during sleep
and share of recovery during sleep is poor), but the index that
describes sleep quality (RMSSD) is at a good level. In these cases, it
usually implies an acute stress state that is more readily reflected in
heart rate level, and the presence of stress or recovery state, but not
yet in heart rate variability. RMSSD is a value that describes how large
heart rate variability is, and it reacts more slowly than heart rate.
Especially young and physically fit people can have strong heart rate
variability, even if other signs of acute stress are present.
The “conflict situation” can also be the other way around, so that the stress chart looks pretty good or good during sleep (a lot of recovery), but RMSSD is very low (poor or hardly moderate). In these cases, it’s good to find out more about the person’s overall situation and make sure that there is no illness or longer-term overload in the background. It should also be determined if the measured resting heart rate value is reliable enough and decrease it if one or more of the conditions during which it’s appropriate to drop the resting heart rate is fulfilled (see: How is the resting heart rate calculated and when to decrease it). The person’s age affects the result strongly; heart rate variability can be naturally rather low when you are older (age is taken into account in the reference values). Certain medications and illnesses can also reduce heart rate variability.