Effects of short-term sleep reduction and aerobic exercise on metabolism and inflammation in healthy adults

The purpose of this study was to explore the effects of short-term sleep reduction on metabolic variables at rest and during acute aerobic (AE) exercise in healthy adults. This study followed a within subjects, repeated measures design. Following resting measures, recreationally active adults (n = 11; 5 female, 6 male; 26.4 ± 5.4 yrs) completed a 45 min AE challenge on a cycle ergometer at 70 % of their VO₂max after 7 nights of habitual sleep (CON) and then 7 nights of sleep reduction (SR) (i.e., sleeping ∼3 h less per night). Carbohydrate and fat oxidation rate, and energy expenditure were assessed via indirect calorimetry. Soluble TLR4 (sTLR4) and IL6 in the blood was assessed via ELISA. Results show sleep was reduced 31 % (p ≤ 0.05) during the SR period (CON: 8.1 ± 0.3 h/night; SR: 5.4 ± 0.2 h/night). Sleep efficiency increased (+5 ± 2 %), while average number of awakenings (-42 ± 4 %) and sleep fragmentation index (-24 ± 8 %) decreased in SR (all p ≤ 0.05). SR increased resting carbohydrate oxidation (+45 ± 1 %), kcals from carbohydrates (+45 ± 1 %), and total kcal utilization (+23 ± 0 %) compared to CON (all p ≤ 0.05). Seated resting heart rate increased 5 ± 0 % (p ≤ 0.05), while mean arterial pressure decreased 3 ± 0 % (p ≤ 0.05) following SR. Resting circulating sTLR4 and IL6 remained unchanged following SR (p > 0.05). IL6 increased significantly after AE in both CON (+161 ± 68 %) and SR (+133 ± 37 %), with no difference between groups, while sTLR4 remained unchanged (p > 0.05). Metabolic and cardiovascular responses during exercise were not different between CON and SR (p > 0.05). Average RPE during AE was higher in SR than CON (+3 ± 0 %, p ≤ 0.05). These findings show that short-term sleep reduction influences resting metabolic and cardiovascular function.