Garmin Stress Metric

Your nightly stress levels probably are (and should) be "rest" (preferably <15), so to get an average stress of 30-35, you have to have higher stress during the day. Also, having constant "low stress" without rest periods during the day could already be classified as "Stressful Day".

But Garmin stress metrics are not super reliable, and mostly measure physiological stress anyway (not mental stress). Also, if you don't always start an activity when running, walking, etc, that might raise the average stress considerably (since those kinds of activites are high physiological stress no matter what). Recording that kind of exercise as an activity excludes those periods from average stress.

Bitti said:

Also, if you don't always start an activity when running, walking, etc, that might raise the average stress considerably

Not really, since Stress is not being measured when you move anyway. HRV (hence stress) can be (relatively) reliably measured only when you stay still (unless you use a chest strap), hence Garmin stops measuring stress as soon as you start moving, regardless whether you record it as an activity or not. On the graph, it is then marked gray as Active.

As to the question in the OP - we could better guess what the reason is, if we saw user's Stress graph of that day (and a few others for a comparison). Though generally, what Bitti wrote (no or few low-stress rest periods during the day) is the likely reason.

trux said:

Stress is not being measured when you move anyway

I've noticed myself that this really depends on what kind of "moving" I'm doing. For example, I recently started taking salsa lessons again, and I've noticed that during that kind of dancing (irregular movements, slightly evelated HR, with pauses in between when we watch the teacher) the watch just gives me stress readings of 90-100 for much of the lesson. If I'm walking, it definitely notices that and doesn't record stress.

If you look at the below images from the Garmin Connect App and the evening report on my F8, the app says that I had enough moments to balance out stress reactions, where as the evening report says I've had a stressful day.

It just seems contradictory. Also, isn't the stress an average taken over a whole 24 hour period which includes sleep "rest"? So an average of 34 in a 24 hour period still counts as a "low stress" day (between 26-50) and therefore shouldn't constitute a report of being a "Stressful Day".