1. Nat. Rev. Rheumatol. doi:10.1038/nrrheum.2017.172
Figure 2 Average total energy expenditure for adults under various conditions
Figure 2 | Average total energy expenditure for adults under various conditions. a | Patterns of energy expenditure change as healthy individuals age77. The resting metabolic rate (or basal metabolic rate) is the amount of energy expended by an individual in the morning, 30 minutes after awakening, while lying in bed, relaxed, undertaking no physical activity and in thermoneutral conditions after one night of fasting. Food-induced energy expenditure, the thermogenic effect of food, is ∼10% of the total energy expenditure under normal conditions. Activity-induced energy expenditure depends on the activity itself and whether it is volitional or non-volitional. b | An illustrative example of the average energy expenditure of a healthy 50 year-old individual; an individual with a 'dominant brain' (high levels of psychomotor activity and non-volitional physical activity); and an individual with a 'dominant immune system' (high levels of inflammatory activity and low levels of volitional physical activity). Notably, the energy expenditure of the immune system cannot yet be measured independently of the resting metabolic rate, so in this example the energy expenditure of the immune system is provided according to previous calculations1.
Straub, R. H. (2017) The brain and immune system prompt energy shortage in chronic inflammation and ageing
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