The Effect of Acute Aerobic Exercise on Hemostasis in Obstructive Sleep Apnea

Abstract

Obstructive Sleep Apnea (OSA) is a prevalent sleep disorder affecting 2 – 4% of the middle-aged population. Individuals with OSA have an altered hemostatic balance favoring coagulation that may predispose them to cardiovascular disease and/or myocardial events. Although the resting hemostatic balance is well understood, the exercise response is less described. PURPOSE: To determine the hemostatic response after acute aerobic exercise in Obstructive Sleep Apnea. METHODS: Eighteen males (nine OSA vs. nine Controls) aged 41 + 13 yrs. and 28.4 + 3.5 BMI were recruited from the university and local community without evidence of cardiovascular, pulmonary, or metabolic disease. Apnea-Hypopnea Index (AHI) > 5 was criteria for OSA. Subjects performed a treadmill exercise test at 35% and 70% predicted VO2reserve during the morning hours. Pre exercise blood samples were obtained after 15 minutes supine rest and within 2 minutes following exercise. Repeated Measures ANOVA were performed for Factor VIII antigen, tPA antigen, tPA activity, and PAI-1 activity. Correlational analysis compared resting and post exercise hemostatic factors with age, BMI, and AHI. RESULTS: Mean AHI was 13.00 + 12.6. No exercise x condition interactions were observed for hemostatic markers. There was a main effect for exercise in Factor VIII, tPA antigen, and tPA activity in both groups. PAI-1activity tended to be elevated in OSA (145%) compared to controls which remained after exercise (205%) (P = 0.05). Post exercise FVIII:Ag correlated with BMI (r = 0.52), while resting tPA:Ag correlated with AHI (r = 0.49), and age (r = 0.50). CONCLUSION: The hemostatic response after acute aerobic exercise is unaffected in mild OSA although PAI-1 activity seems to be elevated. BMI is correlated with FVIII:Ag, while tPA:Ag is associated with AHI and age.