High-impact loading on the skeleton is associated with a decrease in glucose levels in young men.
OBJECTIVE
The skeleton has been suggested to be involved in energy metabolism through osteocalcin (OC), an osteoblast-specific molecule. The objective of this study was to investigate whether high-impact (HI) exercise stimulating bone formation would lead to changes in glucose and lipid metabolism independent of cardiorespiratory effects and whether OC mediates this association.


METHODS
Prospective intervention study.


METHODS
Fifty men aged 20-32 years were allocated to an intervention group or a control group. The intervention group completed six different types of jumps in sets of five, with the frequency of these exercises gradually increasing over 8 weeks. At baseline and after 8 weeks, glycerol concentrations were measured in fat tissue as a marker of lipolysis using microdialysis. Blood samples were assayed for OC and markers of glucose and lipid metabolism. Physical activity was measured using an accelerometer.


RESULTS
After adjustment for confounders at baseline and changes in physical activity during the intervention period, the intervention was associated with a decrease in levels of glucose (P = 0·04), adrenalin (P = 0·03) and OC (P = 0·04) after adjusting for baseline levels and changes in physical activity. No other differences between the groups were significant, although the trends of the metabolic variables favoured the intervention group.


CONCLUSIONS
The results of this study suggest that HI loading on the skeleton may affect glucose metabolism independent of the level of aerobic exercise.
Department of Surgical and Perioperative Sciences, Umeå University, Sweden.
Peder
P
Wiklund
Anna
A
Nordström
Magnus
M
Högström
Håkan
H
Alfredson
Patrik
P
Engström
Thomas
T
Gustafsson
Paul W
PW
Franks
Peter
P
Nordström
D000273:Adipose Tissue / Q000737:chemistry; D000328:Adult; D001786:Blood Glucose / Q000032:analysis*; D001842:Bone and Bones / Q000502:physiology*; D004837:Epinephrine / Q000097:blood; D015444:Exercise / Q000502:physiology*; D005990:Glycerol / Q000032:analysis; D006801:Humans; D008066:Lipolysis; D008297:Male; D011446:Prospective Studies; D016474:Weight-Bearing / Q000502:physiology*
D001786:Blood Glucose; D005990:Glycerol; D004837:Epinephrine