Changes in hematopoietic stem cell numbers following acute exercise in non-athlete marathon runners

Hematopoietic stem cell (HSC) transplant is one of the curative methods for some patients with hematological malignancies. Granulocyte colony-stimulating factor (G-CSF) is the most common drug used to mobilize CD34⁺ cells, generally found in small numbers. Recent evidence showed that exercise causes transient mobilization in HSC. However, the type and intensity of exercise have not been fully revealed. We aimed to detect a significant increase in stem cell levels following 60 ​min of running at a personalized running pace.

Eighteen runners, 48.2 ​± ​1.9 years with peak oxygen consumption of 46.2 ​± ​1.4 ​ml/kg/min, were enrolled in the study. The cardiopulmonary exercise test was performed to determine the individual running pace, and the participants ran 60-min on a treadmill at an intensity close to their ventilatory threshold (VT). The blood sampling for HSC count was performed before, immediately after, at the 1st, 4th and 24th hour after the 60-min running.

The CD34⁺ HSCs were 13.9 ​± ​2.3 ​cells/μl before and significantly increased immediately after to 19.5 ​± ​3.6 ​cells/μl (p ​< ​0.05). The consecutive HSC counts were 15.3 ​± ​2.2, 19.5 ​± ​4.8 and 15.1 ​± ​3.4 ​cells/μl at the 1st, 4th, and 24th hour, respectively.

The individual data showed that some runners had higher HSC levels than the transplantation limit before and after the 60-min running trail, which was maintained for 24 ​h. Pre-running high CD34⁺ HSCs may reflect an adaptive response to regular exercise, with a 60-min run near the VT further elevating HSCs. Individualized exercise may be a valuable tool to mobilize the CD34⁺ HSCs in peripheral blood for donors.