What Causes Lowering Of Body Temperature During Nights?

My husband has a low body temp everyday. He complains of being cold alot. At night he will be freezing and cant warm up and then he will start sweating a lot and fells very hot. He appears to be healthy, works out with weights, but doesnt eat very well. He uses alot of suplements and always have. (no steroids). He has always had an acid problem. Takes alot of antacids, burbs alot, diarrhea.He is 43, about 172 lbs, medical history: His parents-Parkinsins disease, gout, high blood pressure, high cholestrol. As for him, nothing except acid reflux.