Hello, The hot flashes can be due to multiple reasons and to give an accurate without lab investigation it will be tough. The causes can be - increased uric acid levels, varicose veins or degenerative disc disease of the lumbar spine. Follow a step by step procedure of lab test so it can help investigate it properly. Start with blood and urine test then the Doppler scan of the lower limb veins and lastly the MRI of the lumbar spine. Based on the findings we can help conclude what could be causing this. Also, smoking, and drinking not doing doesn t mean there can not be pathological changes. Pathological changes can happen at any time. Smoking and drinking are the precipitating factors and not the actual reasons. Hope I have answered your query. Let me know if I can assist you further. Regards, Jay Indravadan Patel, Physical Therapist or Physiotherapist