Endurance training attenuated the intermittent hypoxia-induced increase in chemoreflex sensitivity (pretraining Δ 0.045 vs. posttraining Δ -0.028; P=0.045) in healthy subjects.
Does endurance training attenuate the effect of intermittent hypoxia on peripheral chemoreflex sensitivity in healthy humans?
Endurance training attenuates chemoreflex sensitization to intermittent hypoxia in healthy subjects, suggesting a potential mechanism for the benefits of exercise in cardiovascular disease.
p-value: p=0.045
Patients with heart failure and sleep apnea have greater chemoreflex sensitivity, presumably due to intermittent hypoxia (IH), and this is predictive of mortality. We hypothesized that endurance training would attenuate the effect of IH on peripheral chemoreflex sensitivity in healthy humans. Fifteen young healthy subjects (9 female, 26 ± 1 yr) participated. Between visits, 11 subjects underwent 8 wk of endurance training that included running four times/wk at 80% predicted maximum heart rate and interval training, and four control subjects did not change activity. Chemoreflex sensitivity (the slope of ventilation responses to serial oxygen desaturations), blood pressure, heart rate, and muscle sympathetic nerve activity (MSNA) were assessed before and after 30 min of IH. Endurance training decreased resting systolic blood pressure (119 ± 3 to 113 ± 3 mmHg; P = 0.027) and heart rate (67 ± 3 to 61 ± 2 beats/min; P = 0.004) but did not alter respiratory parameters at rest ( P > 0.2). Endurance training attenuated the IH-induced increase in chemoreflex sensitivity (pretraining: Δ 0.045 ± 0.026 vs. posttraining: Δ −0.028 ± 0.040 l·min −1 ·% O 2 desaturation −1 ; P = 0.045). Furthermore, IH increased mean blood pressure and MSNA burst rate before training ( P 0.2). All measurements were similar in the control subjects at both visits ( P > 0.05). Endurance training attenuates chemoreflex sensitization to IH, which may partially explain the beneficial effects of exercise training in patients with cardiovascular disease.
Miller et al. (Fri,) conducted a other in Healthy humans (n=15). Endurance training vs. No change in activity was evaluated on Intermittent hypoxia-induced increase in chemoreflex sensitivity (p=0.045). Endurance training attenuated the intermittent hypoxia-induced increase in chemoreflex sensitivity (pretraining Δ 0.045 vs. posttraining Δ -0.028; P=0.045) in healthy subjects.