In Sanskrit word "rechaka" means exhale. Common jargon heard in any yoga training hall.

Usually rechaka is associated with marshalled pranayama practice ie. used by instructor to inform aspirants to exhale (possibly after a while of sustained breath retention ie. kumbhaka).

When feeling really ill and yet in a yoga shala, rechaka may sound and feel like great relief; especially when your nose runs and you can't breath very well. Probably next puraka will make you think the real reason why did you drag your sorry ass to a training hall when you really should have stayed in bed (well, one can always do the practice, it's just after the practice when it hurts...).

See also puraka.