I am 70 years old. Last Dec. 8th my sgpt was 70 only , 72 was the upper normal limit. Last Jan.28th my sgpt went up 122. My ultrasound indicated I have fatty liver. I do a lot of strenuous exercises. Could the strenuous exercises contributed to the abrupt rise in my sgpt  or is it caused purely by my fatty liver condition?
No, Its mainly because of your fatty liver. It needs to be evaluated further with LFT. Considering your age, Blood test including AFP, Bag, anti HCV and ferritin should be done