When young men slept less, their body’s internal temperature dropped slightly over two days, suggesting their body’s natural daily temperature cycle was disturbed.
Scientific Claim
Three nights of shortened sleep (3.5 hours per night) in healthy young men caused a small but statistically significant reduction in 48-hour mean core body temperature (from 36.75°C to 36.68°C, p=0.016), indicating a disruption in thermoregulatory rhythm.
Original Statement
“The 48-h mean CBT decreased significantly during the 3.5-h sleep condition compared with the 7-h sleep condition (7-h sleep, 36.75 ± 0.11 °C; 3.5-h sleep, 36.68 ± 0.14 °C; p = 0.016).”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
definitive
Can make definitive causal claims
Assessment Explanation
Continuous, objective CBT measurements under controlled conditions with statistical significance (p=0.016) support definitive causal language. The effect size is small but clearly measured.
Evidence from Studies
Supporting (1)
Effect of shortened sleep on energy expenditure, core body temperature, and appetite: a human randomised crossover trial
When these men slept only 3.5 hours a night for three nights, their body temperature dropped slightly but noticeably—proof that not getting enough sleep messes with how the body controls its temperature.