What’s Happening In Your Blood After a Workout

What is going on in your blood during recovery? And when are you actually recovered? Scientists looked at markers for inflammation and injury and how long they stick around after a workout.

When it comes to exercise, recovery is the name of the game. Being able to recover faster, and having a better recovery routine will make or break any athlete’s long-term success. Understanding this critical component of exercise is of the utmost importance.

A variety of things occur to our body during and intense exercise. Muscle damage is one such event, and can result in the delayed onset muscle soreness (DOMS) with which we are all familiar. This muscle damage leads to inflammation that can persist for some time, and which may be responsible for signaling various recovery mechanisms in the body. A recent study in the Journal of Strength and Conditioning went into detail about each of these processes and how long they take.

In the study, researchers subjected the participants to a workout designed to induce a need for recovery. They then tested the blood of each subject three times that same day following the exercise. They tested again a full day, two days, and three days afterward. The participants were elite cyclists who did a squat and bench workout of six sets each, and then cycled for an hour. The workout was pretty intense, probably more so than a normal workout, but within the realm of something a person might actually do.

Researchers found that strength was reduced by about 14% three hours after exercise, but had returned to normal some time between twelve and 24 hours later. Good thing for those of us doing two-a-days.

Researchers also found injury markers in the blood, indicative of the muscular damage that had been done. These took longer to return to normal than the strength, being elevated still after a full day, but returning to normal after 48 hours. The researchers did note that other studies indicated these markers typically took longer to show up and then return to normal, being as long as 72 hours after exercise.

In addition to injury, participants experienced an immune response as well. First, there were neutrophils, which are a kind of white blood cell that removes cellular debris, essentially cleaning out the blood from damaging waste post exercise. These appeared within three hours and were gone after a day. This would indicate a good window in which to keep blood flow high through massage and other recovery means. You don’t want neutrophils to hang out for too long or they may damage the cells as well.

Second to appear were the lymphocytes, which didn’t begin showing up until twelve hours and stuck it through the three days of the study. These probably helped mediate larger cellular damage, but appeared to decline in the presence of antioxidants, and the researchers suggested that recovery was more or less complete by 72 hours.

Interestingly, researchers also learned that the inflammation caused by exercise was only local to the damaged muscles, and had no systemic effect after exercise. The oxidative stress markers also seemed to be non-existent, which they attributed to these particular athletes having a greater level of health.

Ultimately it was inflammation that carried the greatest recovery time within the 72-hour window. The inflammation was ameliorated by white blood cells carried in the blood, and I would guess could be hastened by methods that improve blood flow. I’d also suggest that this study shows people may be waiting too long between working the same muscle, which seemingly needs only about three days to recover.


1. Artur Bessa, et. al., “Exercise intensity and recovery: Biomarkers of injury, inflammation and oxidative stress,” Journal of Strength and Conditioning Research, DOI: 10.1519/JSC.0b013e31828f1ee9

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