Torpor is a state of decreased physiological activity in an animal, usually by a reduced body temperature and metabolic rate. Torpor enables animals to survive periods of reduced food availability. A torpor bout can refer to the period of time a hibernator spends at low body temperature, lasting days to weeks, or it can refer to a period of low body temperature and metabolism lasting less than 24 hours, as in “daily torpor”.
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Human beings are homeotherms. Maintaining a consistent body temperature of between 36 to 38 degrees is a homeostatic requirement for optimal enzyme function and metabolic health (fig 1). Poikilotherms will have four to ten enzyme systems that operate at different temperatures but because their metabolism is variable and generally below that of homeothermic animals, maintaining a large brain is generally beyond poikilotherm animals. The metabolism of poikilotherms favors strategies such as ambush hunting rather than stalking-sprinting or persistence-endurance type hunting with it’s high movement cost. As they do not use their metabolisms to heat or cool themselves, total energy requirement over time is low and for the same body weight, poikilotherms need only 5 to 10% of the energy of homeotherms.
A consistently low-morning-body temperature is associated with ageing and chronic stress and is a symptom of overtraining syndrome (OTS) in endurance athletes (fig 2).
Aside from unintelligent training behaviour (see BTR training zones), the biggest influence on ‘homeothermic ability’ is eating behaviour and nutrition. The low–carbohydrate diets and ‘intermittent fasts’ that are gaining popularity amongst the ‘barefoot running’ and ‘natural movement’ communities create stressful levels of gluconeogenesis that reduce the liver’s ability to convert circulating levels of inactive-thyroid hormone (T4) to the active form (T3). The amount of circulating T3 in the body is the biggest influence on cellular metabolism and heat production (thermogenesis). The low levels produced by the liver during fasting and low-carbohydrate dieting are responsible for the reduced Basal Metabolic Rate (BMR) observed in each phase of yo-yo dieting.
A low-carbohydrate diet invariably implies a high fat intake and/or high protein intake which, in western society, invariably implies a high PUFA (polyunsaturated fat) intake (fig 3) due to modern-industrialised-agricultural methods. The ‘essentiality’ of PUFAS (both omega 6 and omega 3) is open to debate but the physico-chemical realities of the autoxidation rates and free radical production of highly unsaturated oils at mammalian body temperatures is not (fig 4).
When the metabolic ‘insult’ of excessive lipoprotein oxidation (rancidity) due to high PUFA intake is added to the metabolic ‘injury’ of excessive gluconeogenesis created by low-carb dieting and fasting, the normally-stable homeothermic ability of mammalian physiology becomes unstable, and body temperatures can drop dramatically in response to environmental temperatures, leading to torpor and hibernation (fig 5).
BTR Considers the combination of low-carbohydrate intake, intermittent fasting and high PUFA intake is the perfect diet plan for Zombies (fig 6).
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