What Constitutes Adaptive Thermogenesis

The quantitative assessment of adaptive thermo-genesis in the regulation of body weight and body composition is hampered by difficulties in determining which component(s) of energy expenditure may be contributing importantly to the changes in metabolic efficiency. As depicted in Figure 2, energy expenditure in the resting state is measured as basal metabolic rate (BMR) or as thermic effect of food (classically known as the specific dynamic action). Changes in the thermic effect of food (as percentage of calories ingested) or resting energy expenditure (after adjusting for changes in fat-free mass and fat mass) can be quantified, and they reflect changes in metabolic efficiency and hence in adaptive changes in thermogenesis. In contrast, any change in heat production from what is generally labeled nonresting energy expenditure is more difficult to quantify. The efficiency of muscular contraction during exercise is low (~25%), but that of spontaneous physical activity (SPA)— including fidgeting, muscle tone and posture maintenance, and other low-level physical activities of everyday life—is even lower since these essentially involuntary activities comprise a larger proportion of isometric work that is simply thermogenic. Since actual work done on the environment during SPA is very small compared to the total energy spent on such activities, the energy cost associated with SPA

How To Reduce Acne Scarring

How To Reduce Acne Scarring

Acne is a name that is famous in its own right, but for all of the wrong reasons. Most teenagers know, and dread, the very word, as it so prevalently wrecks havoc on their faces throughout their adolescent years.

Get My Free Ebook

Post a comment