Early hunter gathers had fewer communicable disease risks due to vastly lower population sizes. So, for example they did not get the seasonal flue. Consider, there was lot's of EU to America disease spread, but almost nothing went the other way. Despite the fact that south America had fairly large scale farming and population growth.

Excluding communicable diseases, most people stay fairly health until 50+ and many hunter gathers likely lived into there early 90's. Infection likely a major risk, but antibiotics are very recent and less necessary than frequently assumed.