The Effects of Combined Fasting and Exercise on Inflammatory Cytokine Concentrations in Healthy Adults: A Randomized...

The object was to assess the effects of adding exercise to a 36-hour fast on the inflammatory cytokines IL-6, TNF-α, and MCP-1. The study was a randomized crossover design with counterbalanced conditions in community members living near a single academic institution. Participants included twenty healthy adults (11 male). The intervention consisted of two 36-h water-only fasts, one of which was initiated with a bout of treadmill exercise. Venous blood was taken at baseline, 12-h, 24-h, and 36-h of fasting. Area under the curve and timepoint analyses were computed. The area under the curve for MCP-1 was 210.4 ± 61.4 pg/ml higher in the fasting combined with exercise condition compared to fasting alone (F = 4.69, p = 0.04). No difference between conditions was observed in areas under the curve for IL-6 (F = 0.02, p = 0.88) or TNF-α (F = 3.74, p = 0.06). MCP-1 concentrations decreased over the course of both conditions (F=19.77, p < 0.01) with much of the reduction taking place between hours 12 and 24 (F=19.77, p < 0.01). Concentrations of IL-6 remained unchanged (F = 0.85, p = 0.48) while TNF-α increased (F=8.60, p < 0.05) in both conditions. A single fast has a mixed impact on the cytokines MCP-1, TNF-α and IL-6. MCP-1 decreases, while TNF-α fluctuates in a diurnal pattern, and IL-6 experiences no change during a water-only fast. Adding exercise to the beginning of a fast diminishes the decline in MCP-1 but has no impact on TNF-α or IL-6.