Plasma Leptin and Exercise

Abstract

The cloning of murine and human obese genes in 1994, and the subsequent identification that the product of the obese gene, leptin, is secreted from adipose tissue, stimulated a tremendous amount of interdisciplinary interest in adipose tissue endocrinology and the potential role of this tissue in the regulation of energy balance. Exercise, with concomitant changes in fuel flux, systemic hormone levels and energy expenditure, may contribute to the regulation of plasma leptin levels and presumably, leptin action. The initial work characterising the leptin-exercise relationship was equivocal. Cross-sectional studies provided some mixed evidence regarding the relationship between aerobic capacity or habitual physical activity and plasma leptin. In contrast, studies on acute bouts of exercise and exercise training interventions have, with few exceptions, suggested that exercise does not alter systemic leptin independent of changes in fat mass. In general, these studies did not carefully control for energy balance, and sampled only a single fasting plasma leptin level. Two recent studies utilising experimental designs in which energy balance was controlled and 24-hour profiles of plasma leptin were determined have provided the most compelling evidence to date of the interaction between exercise, energy balance and systemic leptin in humans. These studies provide a clear explanation for the apparent lack of an acute effect of exercise on systemic leptin and underscore the importance of clearly defining the balance between energy intake and energy expenditure when studying the physiology of leptin. The aim of this brief review is to provide an overview of the interaction between energy expenditure during physical activity and systemic leptin level. Special emphasis will be placed on those studies in which energy intake/balance was carefully controlled.

Preserved Bone Health in Adolescent Elite Rhythmic Gymnasts despite Hypoleptinemia

“…Recent studies have provided the most compelling evidence to date of the interaction between exercise, energy balance and systemic leptin in humans [25]. In the present study, there was a negative correlation between physical activity and energy balance (r = –0.60, p < 0.01) probably due to its positive correlation with energy expenditure (r = 0.80, p < 0.001).…”

Effects of long-term forced exercise training on body mass, energy metabolism and serum leptin levels inApodemus chevrieri(Mammalia: Rodentia: Muridae)

“…However, it may be not a good indicator under an unstable state (Hickey & Calsbeek 2001). In the present study, there was a positive relationship between serum leptin levels and body fat mass in the control group, but no obvious tendency in the exercise-trained group.…”

Effect of Heavy Increase in Training Stress on the Plasma Leptin Concentration in Highly Trained Male Rowers

“…In humans, the systemic leptin level has been reported to be proportional to the body fat mass [2, 3]. In trained subjects, the circulating leptin level is low, and even at biologically extremely low levels of body fat, the leptin concentration is closely related to the body fat content in male athletes [3, 4]. …”

“…An exercise-mediated negative energy balance may contribute to the regulation of plasma leptin levels and presumably leptin action [3, 4]. Furthermore, it has recently been suggested that the regulation of leptin may also depend on factors at the metabolic level associated with certain long-term exercise regimens [4].…”

“…Furthermore, it has recently been suggested that the regulation of leptin may also depend on factors at the metabolic level associated with certain long-term exercise regimens [4]. Exercise training studies have generally suggested that changes in plasma leptin are dependent upon concomitant reductions in body mass [3]. However, systematic training over several years has usually led to profound changes in body composition with a strong reduction in total body fat mass as compared with sedentary controls [3].…”