The following is shared by Reb Aharon Rubin, author of Eye to the Infinite, in response to our post on the origins of yoga…
The following is a bit delicate.
The (Jewish) meditations described by Abulafia might increase certain yetser horas (inappropriate desires) if one is not vigilant and holy; he himself refers to the point.
'Prophetic meditations' need extra added vigilance because one is drawing down spiritual energy via certain sefiros, which, if one is not pure, could give G-d forbid more energy to somewhere else.
Obviously this is a far cry from what you are describing (with yoga) but is the reason why the Talmidei Baal Shem stressed holiness and vigilance in this area, as part of their derech [the stress on davening, meditation, love and fear of G-d and use of the emotions in attaching to G-d] requires greater cleanliness in areas of holiness.