0802 Impact of High Intensity Acute Exercise on Idiopathic RLS Symptoms: Preliminary Results from the PEARLS Study

Introduction Restless legs syndrome (RLS) is a sensorimotor sleep disorder whereby chronic exercise represents one of the most promising non-pharmacological approaches for managing symptoms, but some parameters of exercise (e.g., short-term high intensity) anecdotally exacerbate symptoms. This is the first study to systematically examine the effect of an acute exercise bout in adults with RLS. Methods Untreated, sedentary adults (N=12) with moderate-to-severe idiopathic RLS completed a submaximal cardiopulmonary exercise test to fatigue and maximal lower-extremity muscle strength testing. All participants completed the Self-Administered International Restless Legs Syndrome Study Group (sIRLS) Scale adapted for 24-hours daily for seven days starting two days before testing (pre) and continuing for five days post-testing, with primary outcomes being total score (range=0-40) and visual analogue scores (VAS; range=0-100). Results All participants were women; mean age=50 (range=24-70); mean baseline sIRLS=18 (range=11-25). Repeated-measures ANOVA indicated no statistically significant day-to-day difference in sIRLS total scores (F[4,40]=2.03, p=0.109) or VAS scores (F[4,40]=1.727, p=0.163) across the seven-day period. The night immediately after acute exercise did not differ significantly from pre-exercise for average sIRLS (mean diff=–2.17; p=0.057) or VAS scores (mean diff=–6.8; p=0.222). Individual responses varied, whereby three (25%) participants reported an increase in symptoms (all < 3 points), while nine (75%) reported reductions, with three (25%) reporting >3 point change (delta range –5 to –11), surpassing the minimal clinically significant change for this scale. For VAS, four (33%) participants reported an increase (delta range= 2 to 16) and seven (58%) reported a reduction in symptoms (delta range=–2 to –51). Conclusion These preliminary results did not produce statistically significant day-to-day changes in RLS severity following acute, high-intensity exercise. A partial eta-squared of 0.17 suggests a medium-to-large effect size, implying a potentially meaningful pattern that the study was underpowered to detect. Inter-individual variability immediately post-exercise aligns with our prior work. Long-term effects of exercise remain to be studied. Support (if any) Supported, in part, by the Sleep Research Society Foundation, the Stanford University School of Medicine Department of Psychiatry & Behavioral Sciences 2024 Trailblazing Trainee Award Program, the Restless Legs Syndrome Foundation, and the American Academy of Sleep Medicine Foundation.