Hello, Dizziness and sweating during intercourse commonly occurs due to anxiety, low blood pressure or low blood sugar. It can occur as a side effect to certain medications like Viagra, Levitra etc. It may also occur due to positional vertigo due to changing of the positions too fast. The cardiac symptoms may trigger dizziness and sweating due to arrhythmia caused by a large amount of Adrenalin released due to sexual activity. Get him have a thorough medical check up to rule out any developing cardiac pathology, middle ear problem (BPPV), CBC for diabetes, lipid function tests, urinalysis etc. Keep him well hydrated to maintain the blood electrolyte levels to normal. Let him take home made food, avoid sex for a couple of days, stay away from addictions if any, do regular exercises. Hope I have answered your query. I will be glad to answer any further question about this. Take care. Regards, Dr. Nupur K General & Family Physician