As a general rule, Kapalabhati should not be recommended for women during pregnancy and menstruation and those who suffer from high blood pressure, vertigo, fluid in the ears, hernia, gastric ulcer, active heart disease, a bleeding nose, epilepsy, glaucoma, slipped disc.
During kapalabhati, you use your abdominal muscles to pull inwards to exhale effortfully, it influences spine and back muscles as well. So, if you are suffering from lower back pain, it is better to first treat your back pain properly, in consultation with your physician, physiotherapist or qualified yoga therapist, through proper asanas (bhujangasana, shalabhasana, setubandhasana, tadasana to help strengthen the back muscles etc.), relaxation and diet and avoiding forwarding bending as well, and then practice kapalabhati slowly.
