Core temperature: a forgotten variable in energy expenditure and obesity?

Abstract

A substantial proportion of energy expenditure is utilized for maintenance of the 'warm-blooded' or homoeothermic state. In normally active humans, this compartment of energy output approximates 40% of total energy expenditure. Many mammalian species utilize regulated decreases in temperature, such as hibernation or shallow torpor, as a means of energy conservation. Inherited forms of rodent obesity (ob/ob mouse, fa/fa rat) have lower core temperatures and withstand cold poorly. Obese humans, however, have normal core temperatures. This review addresses the role of core temperature in the metabolic economy of the obese state and raises the possibility that (i) lower temperatures may contribute to the increase in metabolic efficiency that accompanies weight loss in the obese; and (ii) that lower core temperatures may have initiated weight gain in the pre-obese state and that the normal temperatures in the obese may represent metabolic compensation to restore energy balance and limit further weight gain.

Basal body temperature as a biomarker of healthy aging

“…The same model (absence of the time temperature was taken since it was not recorded) explained 2.1 % of the variance in casual temperature with age having a weak negative association (B = −0.009; p = 0.016), which is consistent with previous work (Weinert 2010;Waalen and Buxbaum 2011). Additionally, as basal temperature did not differ between those with and without excess adiposity and none of the body composition parameters were associated with either basal or casual temperature, findings do not support the argument that lower temperature connotes a metabolic handicap that contributes to obesity through lower caloric needs (Grimaldi et al 2015;Landsberg 2012).…”

“…Body temperature declines in all species in response to caloric restriction (Roth et al 2002;Lane et al 1996;Heilbronn et al 2006), and studies of transgenic mice indicate that a lower temperature offers longevity benefits independent of caloric restriction (Conti 2008). Observations that a lower resting metabolic rate (RMR) is associated with better health and longevity Ruggiero et al 2008) also support the potential benefit of a lower basal temperature as approximately two thirds of RMR or 40-50 % of total energy expenditure is required for thermoregulation (Landsberg 2012) and a 1°C rise in temperature translates into a 10-13 % increase in metabolic rate (Du bois 1921 cited in Landsberg 2012).…”

“…Much of the previous research on body temperature in humans has hypothesized that a lower basal temperature is energetically efficient and therefore may predispose individuals to obesity (Rising et al 1992;Landsberg 2012), a major threat to health and longevity. However, this theory has received little empirical support.…”

SIRT1 activation ameliorates hyperglycaemia by inducing a torpor-like state in an obese mouse model of type 2 diabetes

“…Although there is marked variation among 'warm-blooded' animals, considerable energy is used in the maintenance of body temperature and physical activity [26]. Reduction in both, however, can be achieved by bouts of torpor that may manifest as either hibernation or daily torpor.…”

Ethnic differences in resting metabolic rate, respiratory quotient and body temperature: a comparison of Africans and European Australians

“…It was estimated that 20-50 percent of people residing in urban communities in Africa are either overweight or obese [1] and that the mortality rate from chronic diseases in sub-Sahara Africa will increase by 17 % within a decade if urgent measures are not put in place [1]. There are several metabolic predictors of weight gain, and they include a low relative resting metabolic rate (RMR), a high respiratory quotient (RQ), a low core body temperature and low levels of physical activity (PA) among other factors [2][3][4]. While these are not the sole reason for the current obesity crisis, they play a significant role in influencing weight gain.…”