my husband felt sudden weakness in legs, with pain and slight shivering as we do expirience on the onset of fever. but there was no fever. this has happened for the third time in past two months. he remains weak for the next two three days after this, and takes paracetamol or ibugesic plus. his age is 52, he is on amcard lp, bidaily and atorvas and librium at bedtime. his bp remains normal now and when the medicatiopn started two years back his bp used to be 90/140. what could be the reason , before this he was always energetic even after long travels or heavy workload in office. he hgas long office hours involving long sitting.