Passive bilateral leg cycling with concomitant regional circulatory occlusion for testing mechanoreflex-metaboreflex interactions in humans.
PURPOSE
The exercise pressor reflex (EPR) plays a fundamental role in physiological reactions to exercise in humans and in the pathophysiology of cardiovascular disorders. There is no "gold standard" method for EPR assessment; therefore, we propose a new protocol for testing interactions between the muscle mechanoreflex and metaboreflex (major components of EPR).


METHODS
Thirty-four healthy subjects (mean age [± standard deviation] 24 ± 4 years, 22 men) were enrolled in the study. During the study, the hemodynamic and ventilatory parameters of these subjects were continuously monitored using our proposed assessment method. This assessment method consists of an initial 5-min rest period (baseline) followed by 5 min of passive cycling (PC) on an automated cycle ergometer (mechanoreceptor stimulation), after which tourniquet cuffs located bilaterally on the upper thighs are inflated for 3 min to evoke venous and arterial regional circulatory occlusion (CO) during PC (metaboreceptor stimulation). Deflation of the tourniquet cuffs is followed by a second 5 min of PC and finally by a 5-min recovery time. The control test comprises a 5-min rest period, followed by 3 min of CO only and a final 5-min recovery.


RESULTS
Mean arterial pressure (MAP) and minute ventilation (MV) increased significantly during PC (MAP: from 90 ± 9.3 to 95 ± 9.7 mmHg; MV: from 11.5 ± 2.5 to 13.5 ± 2.9 L/min; both p < 0.05) and again when CO was applied (MAP: from 95 ± 9.7 to 101 ± 11.0 mmHg; MV: from 13.5 ± 2.9 to 14.8 ± 3.8 L/min; both p < 0.05). In the control test there was a slight increase in MAP during CO (from 92 ± 10.5 to 94 ± 10.0 mmHg; p < 0.05) and no changes in the ventilatory parameters.


CONCLUSION
Bilateral leg passive cycling with concomitant circulatory occlusion is a new, simple and effective method for testing interactions between the mechanoreflex and metaboreflex in humans.
['Lis|Adrian|A|http://orcid.org/0000-0002-4540-4450', 'Łopusiewicz|Wojciech|W|http://orcid.org/0000-0003-2294-9148', 'Piepoli|Massimo F|MF|http://orcid.org/0000-0003-1124-234X', 'Ponikowska|Beata|B|http://orcid.org/0000-0002-6044-5322', 'Paleczny|Bartłomiej|B|http://orcid.org/0000-0001-9180-9259']
D000328:Adult D001794:Blood Pressure D002319:Cardiovascular System D015444:Exercise D006339:Heart Rate D006801:Humans D007866:Leg D008297:Male D018482:Muscle, Skeletal D012018:Reflex D055815:Young Adult
Circulatory occlusion Exercise pressor reflex Passive cycling Mechanoreceptors Metaboreceptors