Hello, I'm a 64, 6' 3", 188 lb white male that under went surgery one year ago to fuse the C-3/C-4 and C-4/C-5 cervical vertebras due to bulging/ruptured discs. They entered from the right anterior of the neck. This injury was due to wear and tear of an active life(football, water skiing retired US Navy Deep Sea Diver, shipboard welder). Since the surgery I've had moderate problems with swallowing, some constipation but mainly I'm having problems during vigorous exercises (step class and bar exercise classes) especially when I push hard. My legs start shaking, excessive sweating and then tunnel vision ( at which point I remove myself from the class. [It's better to step out than to fall out]). Could this be attributed to the irritation of the vagus nerve from the surgery? Thank you fro your time.