Effects of Recumbent Angle during Cycling on Cerebral Blood Flow Velocity and Rate Pressure Product during Exercise and Recovery

BACKGROUND: The cerebral blood flow velocity (CBFV) and rate pressure product (RPP) have been reported to benefit hemodynamics more during exercise in the recumbent position than during that in the upright position. However, it is unclear which angle is of the greatest benefit to hemodynamics during exercise in the recumbent position. This study aimed to evaluate the effect of the recumbent angle on CBFV and RPP during exercise. METHODS: In a balanced crossover study, 15 healthy volunteers (age, 18.7±1.1 years) were asked to perform the bicycle exercise four times in the upright and at recumbent angles of 67° (R), 47°R, and 15°R, with weekly intervals between each condition. The exercise intensity was set initially at 50 W and increased by 25 W every 2 minutes up to 150 W. CBFV in the middle cerebral artery (MCA) was measured using transcranial doppler sonography. All data were analyzed using two-way repeated-measures analysis of variance. RESULTS: CBFV at 15°R was significantly higher than that in the upright position and at 67°R at 10 minutes recovery (69±16 vs. 56±7 and 58±10 cm/s, respectively; P<0.05). The RPP was significantly lower at 67°R, 47°R, and 15°R than in the upright position immediately after exercise (176±23, 177±22, and 173±26, respectively, vs. 241±42 mmHg×beats/min×10⁻²; P<0.001). CONCLUSIONS: At an angle of less than 67°R, exercise increases CBFV and reduces RPP, relative to those during exercise in the upright position. This hemodynamic effect was most prominent at 15°R, where cerebral circulation was further increased in the recovery phase.

Effects of Recumbent Bicycle Exercise on Cardiac Autonomic Responses and Hemodynamics Variables in Patients with Atrial Fibrillation

BACKGROUND: The purpose of this study is to investigate the safety and efficiency of recumbent bicycle ergometer exercise by observing heart rate variability (HRV) and hemodynamic variables in patients with atrial fibrillation.METHODS: In a balanced crossover study, 13 patients with atrial fibrillation (mean age, 62.2±5.3 years) were asked to perform a bicycle exercise twice, once in the upright position and once in the recumbent position at an angle of 30°, with a 1-week interval between both. The exercise intensity was set initially at 10 W and increased by 15 W every 2 minutes up to 70 W. HRV and hemodynamic variables were measured. All data were analyzed using one-way repeated-measures analysis of variance.RESULTS: Low-frequency normalization in HRV was increased with no intergroup differences immediately after exercise. The rate pressure product was significantly lower in the recumbent than in the upright position right after exercise (104.8±14.3 vs. 151.8±51.4 mmHg×beats/min×10⁻², P < 0.01).CONCLUSIONS: Recumbent exercise improves the safety and efficiency of cardiac rehabilitation for atrial fibrillation patients by reducing myocardial workload without compromising the activation of the autonomic nervous system that regulates cardiac activity.

Effects of Recumbent Angle during Cycling on Cerebral Blood Flow Velocity and Rate Pressure Product during Exercise and Recovery

BACKGROUND@#The cerebral blood flow velocity (CBFV) and rate pressure product (RPP) have been reported to benefit hemodynamics more during exercise in the recumbent position than during that in the upright position. However, it is unclear which angle is of the greatest benefit to hemodynamics during exercise in the recumbent position. This study aimed to evaluate the effect of the recumbent angle on CBFV and RPP during exercise.@*METHODS@#In a balanced crossover study, 15 healthy volunteers (age, 18.7±1.1 years) were asked to perform the bicycle exercise four times in the upright and at recumbent angles of 67° (R), 47°R, and 15°R, with weekly intervals between each condition. The exercise intensity was set initially at 50 W and increased by 25 W every 2 minutes up to 150 W. CBFV in the middle cerebral artery (MCA) was measured using transcranial doppler sonography. All data were analyzed using two-way repeated-measures analysis of variance.@*RESULTS@#CBFV at 15°R was significantly higher than that in the upright position and at 67°R at 10 minutes recovery (69±16 vs. 56±7 and 58±10 cm/s, respectively; P<0.05). The RPP was significantly lower at 67°R, 47°R, and 15°R than in the upright position immediately after exercise (176±23, 177±22, and 173±26, respectively, vs. 241±42 mmHg×beats/min×10⁻²; P<0.001).@*CONCLUSIONS@#At an angle of less than 67°R, exercise increases CBFV and reduces RPP, relative to those during exercise in the upright position. This hemodynamic effect was most prominent at 15°R, where cerebral circulation was further increased in the recovery phase.

Effects of Recumbent Bicycle Exercise on Cardiac Autonomic Responses and Hemodynamics Variables in Patients with Atrial Fibrillation

BACKGROUND@#The purpose of this study is to investigate the safety and efficiency of recumbent bicycle ergometer exercise by observing heart rate variability (HRV) and hemodynamic variables in patients with atrial fibrillation.@*METHODS@#In a balanced crossover study, 13 patients with atrial fibrillation (mean age, 62.2±5.3 years) were asked to perform a bicycle exercise twice, once in the upright position and once in the recumbent position at an angle of 30°, with a 1-week interval between both. The exercise intensity was set initially at 10 W and increased by 15 W every 2 minutes up to 70 W. HRV and hemodynamic variables were measured. All data were analyzed using one-way repeated-measures analysis of variance.@*RESULTS@#Low-frequency normalization in HRV was increased with no intergroup differences immediately after exercise. The rate pressure product was significantly lower in the recumbent than in the upright position right after exercise (104.8±14.3 vs. 151.8±51.4 mmHg×beats/min×10⁻², P < 0.01).@*CONCLUSIONS@#Recumbent exercise improves the safety and efficiency of cardiac rehabilitation for atrial fibrillation patients by reducing myocardial workload without compromising the activation of the autonomic nervous system that regulates cardiac activity.