GLOSSARY

Sleep Deprivation and Leptin links sleep and leptin with intake and energy-state effects.

Leptin mainly conveys adipose information about energy stores and availability and also responds to intake changes. Its relation to fat mass is not perfectly fixed; reduced intake can affect it before major weight change. High leptin does not necessarily mean greater satiety, nor is low leptin always a separate disease. Leptin resistance is a regulatory concept not conclusively diagnosed from hunger or one concentration alone without clinical context.

Adipose tissue contains several cell types, so adipokines are not restricted to adipocyte secretion. Molecules can associate with inflammation or insulin sensitivity without proving causation or treatment utility. Human and animal sources may differ. Adipokine ratios are not universal athletic targets; assays, units and energy state must be specified. A research pathway cannot alone justify a supplement or establish that changing one circulating protein will improve performance.

Low energy availability means insufficient energy remains after exercise for required bodily functions; it is not synonymous with low carbohydrate or weight loss alone. Problematic exposure can affect reproductive, thyroid, bone and appetite systems with variable patterns. Restoring supply and reviewing training load are central to assessment. One normal hormone or a universal numerical cutoff cannot confirm or exclude every case, so symptoms, history and clinical evaluation must be integrated.

Reduced or increased energy intake can change appetite, storage and expenditure signals; these responses are not simply matters of willpower. A short postmeal change differs from adaptations over weeks of weight change. An energy deficit need not immediately produce large weight loss, and surplus does not become exclusively muscle. In sport, the rate of change, training quality, energy availability and health matter more than pursuing a supposed fat-burning hormone.

For practical use, record meal and training timing, sleep and hunger alongside actual intake and performance trends. When a marker changes, first examine measurement conditions and plausible explanations; food decisions should support adequate supply, tolerance and recovery rather than ending the assessment at one molecular signal or assuming a concentration change automatically establishes a useful intervention.

Hormonal axes use feedback and often pulsatile and time-dependent patterns. A rise can be compensatory and a decline temporarily adaptive, neither diagnosing disease without context. Hormone ratios depend on numerator, denominator, timing and units. Sports nutrition does not aim to maximize every hormone; the practical goal is adequate supply and appropriate physiological responses, evaluated with health and performance rather than an isolated ratio or peak.

Exercise mode, intensity, duration, recruited muscle, training history and prior food influence hormonal responses. Acute changes differ from baseline adaptations after training. Higher concentration does not necessarily mean greater secretion or tissue effect, because clearance, plasma volume and receptors also matter. Performance develops through combined adaptations, so targeting a hormone peak is not sufficient for session design or supplement selection; actual recovery and performance must remain part of evaluation.