[remotemass (OP)]

Is there any research and/or evidence on changes in our ability to identify different smells according to how relaxed one is? For instance, if one is particularly relaxed, with a particularly low heartbeat and very low-stress levels measured with a GSR meter (Galvanic Skin Response) will one be more accurate in identifying different smells?

[chiralSPO]

That's an interesting and testable (falsifiable) hypothesis. I can't think of any mechanism that would significantly influence the ability of recognizing smells based on state of relaxation, but I am no expert.

I think there would be more significant effect by having the smell exposure being in the setting that it is familiar to have the smell. For example, it might be more difficult to identify the smell of sage when in a gymnasium locker room, than when in a kitchen. At the same time, the smell of sweaty feet might be more difficult to identify in the kitchen than in the locker room...

As I understand it, smell and episodic memory are often closely linked (a smell can "take you back" to a specific setting or event in your memories).

One significant complicating factor is that ,often the chemical makeup of a specific smell might have several (to several dozen) different chemical compounds, and the exact precise ratios can have profound influence on what the smell is. And some compounds can smell like one thing at a very low concentration, and something else entirely at higher concentrations!