Introduction: Patients with sleep disordered breathing (SDB) have recurrent arousals that occur at the termination of respiratory events causing large blood pressure (BP) and heart rate (HR) surges; greater than those in healthy adults. This may contribute to sustained hypertension in these patients. The frequency of arousals from sleep increases in older adults, as does prevalence of SDB. However, relatively little is known about cardio-respiratory responses to arousal in older adults. This study tested the hypothesis that the presence of flow limitation on arousal augments cardio-respiratory responses in older adults. Methods: 9 healthy mild snorers (60-75 years) were studied. Continuous positive airway pressure (CPAP) was applied and arousals from stage-2 sleep were induced by auditory tones under 2 conditions: a non flow limited (nFL) condition with clinically effective CPAP levels applied (3.5 ± 0.4 cmH2O) and a FL condition where mild resistance was produced by reducing CPAP pressure (2.7 ± 0.3 cmH2O). The average number of arousals per subject was 14 ± 2 FL and 14 ± 2 nFL. Results: Prior to arousal, FL compared to nFL conditions had lower minute ventilation (Vi, 5.1 ± 0.6 v 7.5 ± 0.6 L/min), tidal volume (Vt, 387.4 ± 41.6 v 571.3 ± 37.8 mL) and peak inspiratory flow (PIF, 16.2 ± 1.7 v 23.0 ± 1.8 L/min) (p<0.05) but similar end tidal CO2 (31.7 ± 2.0 v 35.2 ± 1.0 mmHg), HR (59.0 ± 2.8 v 56.9 ± 2.5 beats/min) and mean BP (70.8 ± 4.1 v 68.0 ± 4.3 mmHg). Following arousal from FL compared to nFL conditions there were greater increases in Vi, Vt and PIF (p<0.01). This was mainly due to lower pre-arousal baseline values in the FL condition, although post-arousal peaks tended to exceed those achieved under nFL conditions (Vi, 12.6 ± 0.7 v 11.5 ± 0.4 L/min; Vt, 1135.7 ± 63.6 v 1043.5 ± 55.0 mL; PIF, 43.0 ± 3.0 v 37.9±1.8 L/min) but these differences were not significant. HR and BP responses were similar between FL and nFL conditions. Conclusion: In agreement with previous observations in young healthy adults, cardiovascular responses on arousal from sleep in older adults are independent of respiratory conditions prior to arousal and the magnitude of respiratory responses on arousal. Hence larger cardiovascular surges associated with events during SDB may not be a consequence of flow limitation.