In reply
We appreciate Ulfberg's comments to our article1 on snoring and headache. The association between snoring and headache has been previously discussed in other articles. It is likely that obstructive sleep apnea could underlie such an association, but this cannot be evaluated in the article because nocturnal measurements were not performed. The mechanism may be sleep fragmentation associated with microarousals, lack of sleep, or other manifestations of troublesome sleep, as suggested by Ulfberg. Other mechanisms may include nocturnal hypoxemia or, maybe, a relationship with the pronounced changes in cerebral hemodynamics during apnea.2