24 Hour Ambulatory Blood Pressure Dipping And Variability Characteristics Following Maximal Treadmill Exercise In Community Dwelling Healthy Older Adults.

Abnormal blood pressure (BP) response to maximal exercise may lead to compromised cardiovascular health. PURPOSE: To examine the 24-hour ambulatory blood pressure response in older adults following a maximal exercise treadmill test. METHODS: Ambulatory BP was recorded every 30 minutes (daytime) and 60 minutes (nighttime) on the day preceding and then 24 hours following a symptom limited maximal exercise treadmill test. Participants were a convenience sample of healthy older adults free of cardiovascular and musculoskeletal limitations who were participants in a community-based exercise program in London, Ontario, Canada. Symptom limited exercise was performed in the AM in a fasted state, during which VO2max was estimated. The study outcomes included mean systolic and diastolic BP (daytime, nighttime and 24-hour), as well as mean change in BP from daytime to nighttime (BP dipping), and BP variability (average real variability [ARV]). Mixed between-within ANOVA was used in the statistical analysis, exploring main effects for time (pretest vs posttest), grouping factors (presence of hypertension [normotensive vs hypertensive], gender [men vs women], and fitness level [low, average and high VO2max]), and interaction effects for time × grouping factors. RESULTS: 11 men and 9 women, mean age 71.5 (SD=5.4) years were included in the analysis. Mean VO2max was 34.8 (SD=7); 10 subjects had documented hypertension. No difference in the mean pre-exercise systolic ABP was 129.2 (120.3-138.1) vs 124.8 (116.7-132.9) and post-exercise systolic ABP was 126.3 (118.8-133.9) vs 122.8 (116-129.6) in normotensive and hypertensive subjects respectively (p=0.7). Nighttime diastolic BP dipping differed according to VO2max groups, whereby it increased in participants with low VO2max, while it decreased in those with average VO2max and high VO2max (p=0.037). As well, post-exercise systolic BP variability was decreased in men but increased in women (p=0.07). CONCLUSIONS: Healthy older normotensive and hypertensive subjects had similar post 24-hour systolic BP dipping. However, nighttime diastolic blood pressure as significantly different according to fitness level and systolic BP variability was reduced in men suggesting low fitness and male gender may alter BP response to maximal exercise in older adults.