Having reigned about Thirty-Two Years, and lived above Sixty, he still had a Sound Body
He completed the time of his reign in two and thirty years, wanting a few months and days, and his whole life extended to about twice that period. At this age he still possessed a sound and vigorous body, free from all blemish, and of more than youthful vivacity; a noble mien, and strength equal to any exertion; so that he was able to join in martial exercises, to ride, endure the fatigues of travel, engage in battle, and erect trophies over his conquered enemies, besides gaining those bloodless victories by which he was wont to triumph over those who opposed him.
Source: Life of Constantine (New Advent)