Basal metabolic rate, and the closely related resting metabolic rate (RMR), is the amount of daily energy expended while at rest in a neutrally temperate environment, in the post-absorptive state (meaning that the digestive system is inactive, which requires about twelve hours of fasting in humans).
- direct calorimetry
measurement of heat actually produced by the organism which is confined in a sealed chamber or calorimeter.
- indirect calorimetry
estimation of the heat produced by means of the respiratory differences of oxygen and carbon dioxide in the inspired and expired air.
Resting metabolic rate (RMR) or Resting energy expenditure (REE) is whole-body mammal (and other vertebrate) metabolism during a time period of strict and steady resting conditions that are defined by a combination of assumptions of physiological homeostasis and biological equilibrium. RMR differs from basal metabolic rate (BMR) because BMR measurements must meet total physiological equilibrium whereas RMR conditions of measurement can be altered and defined by the contextual limitations. Therefore, BMR is measured in the elusive "perfect" steady state, whereas RMR measurement is more accessible and thus, represents most, if not all measurements or estimates of daily energy expenditure.
Resting energy expenditure thyroid
UCP2 and Vitamin D
basal metabolic rate and copper
BMR+and+leptin. Complex relationship
BMR and Aging
As energy production in living organisms mostly depends on oxidative metabolism, BMR may be assumed as a reliable measure of energy production.
As the decrease of the BMR is a common feature of aging and of the increased risk of diseases and death it is worthwhile to describe it in detail.
BMR is evaluated on 30 min timelapse, in resting state.
The actual daily metabolic rate depends on our physical activity and may vary largely on this base. (Basic info on BMR in different species)
Invited Review: Aging and energy balance, 2003 Fulltext
Renormalized basal metabolic rate describes the human aging process and longevity, 2019
The question of why we age and finally die has been a central subject in the life, medical, and health sciences. Many aging theories have proposed biomarkers that are related to aging. However, they do not have sufficient power to predict the aging process and longevity. We here propose a new biomarker of human aging based on the mass‐specific basal metabolic rate (msBMR). It is well known by the Harris–Benedict equation that the msBMR declines with age but varies among individual persons. We tried to renormalize the msBMR by primarily incorporating the body mass index into this equation. The renormalized msBMR (RmsBMR) which was derived in one cohort of American men (n = 25,425) was identified as one of the best biomarkers of aging, because it could well reproduce the observed respective American, Italian, and Japanese data on the mortality rate and survival curve. A recently observed plateau of the mortality rate in centenarians corresponded to the lowest value (threshold) of the RmsBMR, which stands for the final stage of human life. A universal decline of the RmsBMR with age was associated with the mitochondrial number decay, which was caused by a slight fluctuation of the dynamic fusion/fission system. This decay form was observed by the measurement in mice. Finally, the present approach explained the reason why the BMR in mammals is regulated by the empirical algometric scaling law.
How to increase BMR
BMR depends on oxidative metabolism that takes place in the mitochondrion.
HCG: Human Chorionic Gonadotropin