Background: There are regional differences in the response of fat mass distribution to increased physical activity, caloric restriction and hyper-caloric intake. We hypothesized that strict inactivity (bed-rest) would lead to regional differences in fat deposition.
Methods: Twenty-four male subjects underwent 60d bed-rest (2nd Berlin BedRest Study) and remained inactive (n=9), performed resistance exercise plus whole-body vibration (RVE; n=7) or resistance exercise only (RE; n=8). Fat mass was assessed via dual X-ray absorptiometry. Insulin sensitivity was quantified by the euglycemic hyperinsulinemic clamp technique. P-values were adjusted via the false discovery rate method to guard against false positives.
Results: In the inactive subjects, fat deposition differed between body regions (p=0.0005) with android region visceral adipose tissue increasing the most (+29% at end bed-rest), followed by remainder of the trunk (from chin to the iliac crest; +10%) and the arms and legs (both +7%). Insulin sensitivity reduced in the inactive subjects at the end of bed-rest (p=0.036). Resistive exercise alone (RE) did not have a significant impact on regional fat mass changes (p≥0.055). In the resistance exercise plus whole-body vibration (RVE) group, increases in visceral adipose tissue (-14%; p=0.028 versus inactive subjects) and in the arms (arms -8%, p=0.011 versus inactive) were not seen.
Conclusions: We conclude that strict physical inactivity leads to a preferential increase in visceral adipose tissue. Exercise during inactivity can modulate this response.
This work has been published in: Belavý, Möhlig, Pfeiffer, Felsenberg, Armbrecht (2014) International Journal of Obesity http://dx.doi.org/10.1038/ijo.2014.26