Releasatory? Releaseful?

I suggest unwinding: (from M-W)

To unwind:

• to relax and stop thinking about work, problems, etc.

also satisfying:

• providing abundant nourishment; "a hearty meal"; "good solid food";
• that gratifies the need, desire, or expectation of.

I'd use cathartic, from

ca·thar·sis noun \kə-ˈthär-səs\

: the act or process of releasing a strong emotion (such as pity or fear) especially by expressing it in an art form http://www.merriam-webster.com/dictionary/catharsis

I think MW overstates the importance of art though.

You're looking for "relieving". Merriam-Webster gives the following definition of "relieve" as an intransitive verb:

relieve: to bring or give relief

Technically speaking the most suitable word is probably relaxing - assuming the effect OP refers to is much bound up with taut/tight/contracted muscles that need to relax/loosen up.