Abstract
Leptin values are higher in obesity. Physical exercise reduces fat mass (FM) and decreases
leptin levels. Intensity of physical training seems to play a role in reducing circulating
leptin. In 16 obese subjects (8 men and 8 women, age 38.6±3.9 years, BMI 35.9±1.8
kg/m2), leptin was sampled before and after 4 weeks of controlled training. Eight subjects
(4 men and 4 women) performed an aerobic training schedule (Group A), the remainders
an aerobic training program with a bout of work beyond the anaerobic threshold (AT)
(Group B). Training determined a reduction in leptin levels in both groups, which
was significant in Group A (12.2 vs. 27.8 μg/l, p<0.05), even when related to the
change in FM (0.372 vs. 0.762 μg/l/kg, p<0.05). FM decreased significantly in Group
B when compared to Group A (–7.4 vs. –2.6 kg, respectively, p<0.001). While in Group
A the slight loss of FM was aggregated to a significant decrease in leptin levels,
the opposite occurred in Group B. In Group A, leptin lowering was proportional to
the amount of total work performed (p<0.001, R2=0.89). In obesity, a reduction is observed in leptin levels after short-term training,
which is seemingly dissociated from concomitant decrease of FM. Aerobic training alone
appears to be linked to a greater leptin reduction, which is well correlated with
the amount of work performed.
Key words
leptin - insulin resistance - obesity - physical training - anaerobic threshold
