Effects of a six month training program on serum lipids, glucose, insulin and adipose tissue lipoprotein lipase in young overweight females

EFFECTS OF A SIX MONTH TRAINING PROGRAM ON SERUM LIPIDS, GLUCOSE, INSULIN AND ADIPOSE TISSUE LIPOPROTEIN LIPASE IN YOUNG OVERWEIGHT FEMALES There are numerous studies indicating that lipoprotein lipase (LPL) is a key enzyme in establishing the balance between adipose tissue triglyceride stores and muscle energy requirements, in healthy subjects. Its activity, which is reported to be positively related to fat cell size and mass, decreases with caloric restriction and increases with physical activity and training. Loss in muscle mass due to lack of physical activity is a cause of insulin resistance, whereas circulating levels of this hormone increase. To determine the effect of a six month training program on fasting serum triglyceride, total-, HDL- and LDL-cholesterol, glucose and insulin concentrations, and abdominal adipose tissue LPL activity; and to assess any possible relationships with body composition change in young overweight females was the purpose of this study. Seven university students aged 18-21 who were considered to be overweight (mean BMI of 27.9 kg/m2) participated in the training program which consisted of an hour of light physical activity including a 20 min jogging, stretching and aerobics exercises in the gym, for 4-5 days/week. The control group consisted of seven females who were slightly overweight (mean BMI of 24.3 kg/m2), students of the same university, and who did not participate in any regular physical activity. All the subjects were told not to change their dietary habits. The training group lost weight significantly, with an accompanying significant decrease in BMI and body fat ratio. Their VO^max increased as well. The only serum lipid parameter which responded favourably was HDL-C. Similar changes, though not at a significant level, observed in the control group, were suggestive of a seasonal variation. LPL activity increased per unit mass of abdominal adipose tissue in the training group. The relationships between the parameters in question are discussed. Key Words: Adipose tissue, lipoprotein lipase, obesity, body mass index, overweight, fat distribution, high density lipoproteins, lipid metabolism.