My family’s favorites Aroma Therapy oils: Myrtle (single and milder), RC (Respiratory Care) and Breath Again. Latter two are blends. Apply topically, diffuse. I dilute RC and Myrtle with carrier oil (e.g. coconut, olive, jojoba, etc.) for topical application.
Use for anything respiratory-related, even if a cardio activity.
As always, remember that purity and potency are of paramount importance!