- Excessive or undesirable pain during use,
- Dizziness, vertigo, or lightheadedness,
- Pregnancy (use at your own risk),
- Os Odontoideum,
- Bow Hunter's Syndrome,
- Taking blood thinners,
- Previous neck surgery,
- Chiari Malformation,
- Down's Syndrome,
- History of aneurysm or stroke,
- Vertebrobasilar Insufficiency (VBI), or
- Carotid Sinus Hypersensitivity (CSH)