When guys who work out regularly do intense training, their blood DNA levels go up — and go back down when they rest. This might mean DNA levels can show how stressed their bodies are from too much...

When guys who work out regularly do a 12-week strength training program, the more they train, the more DNA floating in their blood goes up — and that might be a sign their body is dealing with hidden inflammation from overdoing it.

After a super intense sprint workout, your body releases a tiny bit of DNA into your blood — and the more tired your muscles feel afterward, the more DNA shows up. This could mean that measuring this DNA helps doctors tell how hard your muscles were pushed.

After just three weeks of short, intense bursts of running, older men had less of a biological marker in their blood that signals stress or damage in the body—this might mean their bodies are under less strain as they age.