Does sleeping in cold temperatures aid in weight loss?

Cold Exposure and Weight Loss: The Evidence

Cold exposure during sleep does not significantly contribute to weight loss, as the small increases in energy expenditure are typically compensated by increased food intake, resulting in minimal impact on overall body weight.

Physiological Effects of Cold Exposure

• Cold exposure increases energy expenditure through thermogenesis, with studies showing approximately 18% increase in energy expenditure during acute cold exposure in individuals with obesity 1.
• Cold exposure activates brown adipose tissue (BAT), which is responsible for non-shivering thermogenesis and can increase metabolic rate 2.
• The thermoneutral zone for humans is around 28-32°C, and housing at lower temperatures (20-22°C) increases energy expenditure by approximately 30% above basal metabolic rate 2.
• Cold exposure stimulates both shivering thermogenesis by skeletal muscle and non-shivering thermogenesis by brown and beige fat 2.

Compensatory Mechanisms Limiting Weight Loss

• Despite increased energy expenditure during cold exposure, food intake typically increases to fully compensate for the additional energy expenditure, resulting in no significant reduction in body weight or adiposity 3.
• Research shows that cold exposure causes a slight increase (10%) in energy intake during the immediate meal following exposure 1.
• Animal studies demonstrate a significant negative dose-response effect between environmental temperature and energy intake, meaning animals eat more as temperature decreases 4.
• In humans, chronic cold exposure (cold acclimation) studies show minimal changes in body weight, with an average compensation of approximately 126% through increased food intake 4.

Sleep Quality and Metabolic Considerations

• Cold exposure during sleep may disrupt normal sleep patterns, as moderate heat or cold exposure has been found to decrease sleep quality 2.
• Sleep deprivation itself can undermine weight loss efforts by decreasing the proportion of weight lost as fat and increasing the loss of fat-free body mass during caloric restriction 5.
• Sleep deprivation blunts the normal nadir body temperature during sleep by disrupting circadian rhythm regulation and altering thermoregulatory mechanisms 6.
• The WHO recommends indoor temperatures between 18-24°C for optimal health and comfort 2.

Practical Considerations for Temperature Regulation

• The thermal environment affects comfort, work performance, and well-being, with conditions that are too cool or too warm causing discomfort and decreased cognitive performance 2.
• The optimal relative humidity in indoor air for health and work performance is between 40-60% 2.
• Putting on a sweater allows indoor temperature to be lowered by 2°C without reducing thermal comfort 2.
• Chronic exertional fatigue and sleep loss, combined with underfeeding, can reduce tissue insulation and blunt metabolic heat production, compromising maintenance of body temperature 7.

Conclusion: Weight Loss and Cold Exposure

• The evidence does not support cold exposure during sleep as an effective weight loss strategy due to compensatory increases in food intake 1, 4.
• Cold exposure produces only small increases in energy expenditure in humans, which are typically offset by increased appetite and food intake 4.
• The discomfort associated with cold exposure further questions its efficiency as an intervention for meaningful changes in body weight 1.
• While cold exposure may transiently improve glucose homeostasis, it does not lead to significant reductions in body weight or adiposity without additional interventions 3.