Effects of nighttime graduated compression tights on overnight changes in lower-limb circumference in healthy young women with subjective leg swelling: A randomized crossover trial

Background: Transient lower-limb swelling may occur in healthy young women during daily life. This study examined whether wearing graduated compression tights during sleep enhanced overnight reductions in lower-limb circumference and affected subjective sleep quality or morning fatigue. Methods: In this randomized, open-label, two-period crossover trial, female university students aged 18–28 years with subjective lower-limb swelling were assigned 1:1 to compression-first or no-compression-first sequences. Each 14-day period was separated by a 7-day washout. With compression, participants wore graduated compression tights during sleep after daytime acclimation. Co-primary outcomes were between-condition differences in overnight circumference change at the ankle, calf, and thigh. Secondary outcomes were subjective sleep quality and morning fatigue. Self-reported morning leg swelling was assessed at each time point. Mixed-effects models were used, with Holm adjustment for three primary outcomes. Results: Forty-six participants were randomized and 44 completed both periods. Compared with no compression, compression resulted in greater overnight reductions at the ankle (least squares mean difference, −0.23 cm; 95% confidence interval, −0.33 to −0.13; adjusted p = 0.0001), calf (−0.35 cm; −0.52 to −0.18; adjusted p = 0.0004), and thigh (−0.28 cm; −0.47 to −0.08; adjusted p = 0.0066). Perceived morning leg swelling was less likely with compression (30.6% vs. 58.4%). The OSA-MA sleep-length factor was lower at Time3 (nominal p = 0.03), but no other sleep-related outcome or morning fatigue differed significantly. No adverse events were reported. Conclusions: Wearing graduated compression tights during sleep enhanced overnight reductions in lower-limb circumference. Although the differences were modest (approximately 2–4 mm) and their clinical importance remains uncertain, the accompanying reduction in perceived morning swelling suggests that these changes may have perceptible relevance to participants. Nighttime compression may facilitate the overnight reduction of transient lower-limb swelling under everyday living conditions.