Chilling Effects: Obesity and Cold Exposure

Abstract

In individuals living with obesity, adipose tissue aids in reducing (H_loss) and also serves as a heat storage compartment. Moreover, lean body mass, which has a higher H_prod than adipose tissue plays a crucial role in energy production and thermoregulation. The extent of resistance to the cold remains underexplored in this population, and it is important to understand these responses given the global obesity rise and its health implications. This study aimed to quantify how various body anthropometric variations affected thermal responses in individuals living with obesity during acute compensable cold exposure. A liquid-conditioned suit, connected to a temperature-controlled water circulating bath set at 10°C, was used for 90 min to elicit a compensable cold response in these individuals. Validated methods regarding subjective thermal comfort and sensations, skin temperature (T_skin; °C), heat production (H_prod; kJ ⋅min⁻¹), metabolic fuel selection and shivering intensity were recorded to determine the effect of obesity (and muscle and fat mass) on thermogenic and thermal responses. Our study revealed that individuals with obesity, like their lean counterparts, manifest an increased H_prod during cold exposure by 1.7 ± 1.3 kJ ⋅min⁻¹. However, this increase was observed to be lesser in magnitude among individuals living with obesity compared to lean ones. We also explored the source of fuel during cold exposure and found that carbohydrate and lipid oxidation collectively accounted for a significant proportion of H_prod, with lipid oxidation dominating at 61%, and carbohydrates at 21%. Regarding muscle activity, it was observed that a decrease in T_skin incited an increase in shivering. However, similar to the metabolic responses, shivering in this cohort was much less pronounced than in lean individuals. The study opens avenues for further research, addressing the implications of repeated cold exposure and different lengths, temperatures, or modalities on individuals living with obesity.