Increase of glucose uptake in human bone marrow with increasing exercise intensity

Human bone marrow is a metabolically active tissue that responds to acute low-intensity exercise by having increased glucose uptake (GU). Here, the authors studied whether bone marrow GU increases more with increased exercise intensities. Femoral bone marrow GU was measured using positron emission tomography and [¹⁸F]-fluorodeoxyglucose in six healthy young men during cycling at intensities of 30% (low), 55% (moderate), and 75% (high) of maximal oxygen consumption on three separate days. Bone marrow GU at low was 17.2 μmol·kg⁻¹·min⁻¹ (range 9.0-25.4) and increased significantly (p = .003) at moderate (31.2 μmol·kg⁻¹·min⁻¹, 22.9-39.4) but was not significant from moderate to high (37.4 μmol·kg⁻¹·min⁻¹, 29.0-45.7, p = .26). Furthermore, the ratio between bone and muscle GU decreased from low to moderate exercise intensity (p < .01) but not (p = .99) from moderate to high exercise intensity. In conclusion, these results show that although the increase is not as large as observed in exercising skeletal muscle, GU in femoral bone marrow increases with increasing exercise intensity at least from low- to moderate-intensity effort, which may be important for bone and whole-body metabolic health.