Aerobic Exercise Training Improves Heart Rate Recovery Activity In Sedentary African Americans With Abnormal Diastolic Function
PURPOSE: African Americans are an at risk population for diastolic heart failure (DHF). Increased Sympathetic Nervous System Activity (SNSa) is strongly associated with DHF. Abnormal diastolic function (ADF) is a precursor to DHF and manifests itself early in the disease process without any other apparent signs or symptoms. Like DHF, ADF is often accompanied by increased SNSa. Heart Rate Recovery (HRR) obtained from a graded exercise test is thought to be an indicator of SNSa. Aerobic exercise training has been shown to decrease SNSa and improve HRR, therefore presenting a potential tool for early intervention for people with ADF. Thus, the purpose of this preliminary study was to investigate the effects of aerobic exercise training on HRR in African Americans with abnormal diastolic function.
METHODS: AA subjects (n=9) ages 45-62, who were sedentary, non-diabetic, non-smoking, and had abnormal diastolic function, but were free of cardiovascular disease, underwent 6 months of aerobic exercise training (3days/week, 65% of VO2max, 40 minutes/day). E’ was measured by Doppler ultrasound during an echocardiographic stress test, and abnormal diastolic function was defined as having an E’ value less than 10 cm/sec. HRR (maximum heart rate obtained during the test minus 4 min heart rate of passive recovery) determined from a sub-maximal graded exercise stress test was used as a surrogate measure for SNS activity.
RESULTS: HRR significantly (p≤0.029) increased (60.22±3.58 bpm vs. 70.22±2.55 bpm) with 6 months of aerobic exercise training. However, aerobic fitness measured via VO2max did not (p≤0.176) change (28.07±2.76 ml/kg/min vs. 30.57±2.94 ml/kg/min).
CONCLUSIONS: Although no improvements in aerobic fitness were observed, likely due to the small sample size, a significant improvement in HRR was seen, which might indicate an improvement in SNSa. Therefore, among individuals at risk for the development of DHF, aerobic training may be a useful tool at altering one associated abnormality associated with its progression, increased SNS activity.
Medicine & Science in Sports & Exercise
Digital Object Identifier (DOI)
Kretzschmar J, Crabbe D, Feairheller DL, Sturgeon KM, Diaz KM, Williamson ST, Veerbhadrappa P, Ling C, Perkins A, McGloon K, Menardy O, Brown MD. Aerobic Exercise Training Improves Heart Rate Recovery Activity in African Americans with Abnormal Diastolic Function. Medicine & Science in Sports & Exercise. 44:5. Supp. 2012.
© 2012 American College of Sports Medicine