Rise of blood pressure with periodic limb movements in sleep and wakefulness.

OBJECTIVE: To measure changes in blood pressure and pulse rate associated with periodic limb movements in sleep (PLMS) in patients with restless legs syndrome (RLS).

METHODS: We measured autonomic activation as indicated by a rise in blood pressure and pulse rate during periodic limb movements in sleep (PLMS) in 8 patients (6 women average age 57.6+/-16.5 yr and 2 men average age 34+/-28 yr) with RLS. The patients had overnight polysomnographic (PSG) recordings with continuous monitoring of blood pressure (BP) and heart rate (HR). The patients were asked to perform voluntary movements mimicking PLMS (Fake PLMS) which served as controls for PLMS during PSG. We analyzed 601 movements: 145 periodic limb movements in wakefulness (PLMW), 173 periodic limb movements in sleep with cortical arousal (PLMSA), 168 periodic limb movements in sleep without cortical arousal (PLMSNA) and 115 respiratory related limb movements (RRLM).

RESULTS: There was a statistically significant rise in systolic blood pressure (SBP), diastolic blood pressure (DBP) after PLMW (SBP 11.7+/-7.6 mm Hg), PLMSA (SBP 16.7+/-9.4 mm Hg), PLMSNA (SBP 11.2+/-8.7 mm Hg) and RRLM (SBP 18.9+/-14.9 mm Hg) which exceeded that seen with Fake PLMS (SBP 3.2+/-3.1 mm Hg) in wakefulness. There were comparable increases in heart rate that did not quite reach statistical significance.

CONCLUSIONS: There is a rise in SBP, DBP and HR with PLMW, PLMSNA, PLMSA and RRLM as compared to Fake PLMS.

SIGNIFICANCE: One possibility is that the concomitant rise in the blood pressure and heart rate after periodic limb movements indicating autonomic activation may have long-term adverse cardiovascular consequences. This remains to be determined in future experiments.