Medicine & Science in Sports & Exercise:
A-36 Exercise is Medicine/Poster - Exercise is Medicine: Effects on Health: JUNE 1, 2011 7:30 AM - 12:30 PM: ROOM: Hall B
Kline, Christopher E.; Crowley, E. Patrick; Ewing, Gary B.; Rowell, Elizabeth A.; Giles, Kelli L.; Blair, Steven N. FACSM; Durstine, J. Larry FACSM; Davis, J. Mark FACSM; Burch, James B.; Youngstedt, Shawn D.
University of South Carolina, Columbia, SC.
(No relationships reported)
Obstructive sleep apnea (OSA) predisposes individuals to significant cardiovascular (CV) morbidity due to the intermittent hypoxia and transient sympathetic surges from nighttime apneas and hypopneas. Heart rate recovery (HRR), an exercise test marker that is predictive of future CV risk, has been found to be blunted in those with OSA compared with matched controls. Although exercise training would be expected to improve CV health in this population, it is unknown whether these improvements would be blunted in those with OSA not undergoing concurrent treatment (e.g., continuous positive airway pressure) due to the underlying effects of OSA.
PURPOSE: To determine the effect of exercise training on HRR in adults with untreated OSA.
METHODS: Forty-three sedentary adults (BMI > 25) with untreated OSA (apnea-hypopnea index [AHI] ≥ 15) were randomized to a 12-week exercise training (EX; n=27) or stretching control group (STR; n=16). EX participants performed 150 min/week of aerobic activity at ∼60% of heart rate reserve and 2 sets of resistance training twice/week. STR participants met twice/week for a ∼30-min flexibility session. Before and after the 12-week intervention, participants performed a maximal treadmill exercise test using a modified version of the Bruce protocol. Following maximal exertion, participants recovered for 5 min at 1.7 mph and 0% incline. HRR was calculated as the difference in beats/min from maximum heart rate (HRmax) at 1, 3 and 5 min into recovery (HRR-1, HRR-3, HRR-5, respectively).
RESULTS: Relative to stretching control following the intervention, exercise training improved HRR-1 (STR: 19.1±7.3 to 18.2±7.4 beats/min, EX: 17.2±8.4 to 20.2±9.3 beats/min; P=.03), HRR-3 (STR: 42.9±12.3 to 42.2±13.4 beats/min, EX: 36.4±11.4 to 42.0±13.6 beats/min; P<.01), and HRR-5 (STR: 48.8±11.8 to 46.3±13.1 beats/min, EX: 40.1±12.2 to 46.5±14.1 beats/min; P<.01). HRrest or HRmax did not change over time between groups (P>.13). In a subgroup with OSA measured before and after the intervention (n=27), changes in HRR were not associated with changes in any marker of OSA severity (e.g., AHI, min of O2 saturation < 90%; each r<.19, P>.35).
CONCLUSION: Exercise training improved heart rate recovery in adults with untreated OSA, and these effects were not associated with changes in OSA severity.