Item Details

abstract

INTRODUCTION: Individuals born with very low birth weight (VLBW) have increased risk for developing hypertension later in life, and early identification of those at risk for developing hypertension is extremely important to prevent or minimize end-organ damage. Although resting blood pressure (BP) is found to be a good predictor of future resting BP, the addition of BP response to an exercise stressor may further enhance the ability to predict future levels of resting BP in both adolescents and young adults. PURPOSE: To determine if BP response to exercise improves the predictability of future resting and ambulatory BP five years later, above and beyond resting BP, in a cohort of VLBW young adults. METHODS: At age 14 years, subjects performed a graded exercise test to exhaustion during which expired gases were measured continuously to determine oxygen consumption (VO2). Systolic (SBP) and diastolic (DBP) BP were measured manually every two minutes during and at peak exercise. The slopes of SBP and DBP in relation to VO2 (ml/kg/min) during exercise were calculated. Five years later, resting BP was measured in triplicate with a mercury sphygmomanometer. Ambulatory BP (ABP) was monitored (Spacelabs 90207) for 24-hours, from which mean 24-hour, awake, and asleep SBP and DBP were calculated. Nocturnal dipping was calculated as percent change from awake to asleep for both SBP and DBP. RESULTS: Sixty participants (40 F) had both exercise data at 14 years of age and resting BP five years later. At follow-up five years later, eight participants had a resting SBP in the prehypertensive range (SBP 120-139 mmHg), four participants had a resting DBP in the prehypertensive range (DBP 80-89 mmHg), and one participant had a resting DBP in the hypertensive range (DBP>90 mmHg). Pearson correlational analysis found that in addition to resting SBP (r=0.637) and DBP (r=0.238), SBP at peak exercise (r=0.340), SBP slope (r=0.283) and DBP slope (r=-0.344) were significantly correlated (p<0.05) with resting SBP at follow-up. Only resting DBP was significantly correlated with follow-up resting DBP (r=0.718). In 32 participants with valid mean awake ambulatory BP data, SBP at baseline (r=0.471) was significantly correlated with mean awake SBP and slope of SBP during exercise (r=-0.470) was significantly correlated with mean awake DBP. In 29 participants with valid average 24-hour, asleep and dipping BP data, resting SBP was significantly correlated with average 24-hour SBP (r=0.464) and average asleep SBP (r=0.390). Resting DBP was significantly correlated with average asleep DBP (r=0.405) and SBP dipping (r=-0.375). Peak SBP during exercise was significantly correlated with average 24-hour SBP (r=0.368). Multiple regression analysis determined that BP response to exercise did not significantly enhance the predictability of future resting BP above and beyond resting BP at baseline. However, resting DBP and slope of exercise explained 27.6% and 19.3% of variance for SBP and DBP dipping at follow-up. CONCLUSION: Results of our study suggest that measurement of BP during exercise is predictive of diminished nocturnal dipping in young adults with VLBW who have increased risk of developing HTN earlier in life.

subject

Ambulatory Blood Pressure

Blood Pressure

Exercise

Follow-up

Prematurity

Very Low Birth Weight

contributor

Crumpler, Jessica Lauren (author)

Nixon, Patricia A (committee chair)

Berry, Michael J (committee member)

Washburn, Lisa K (committee member)

date

2013-06-06T21:19:27Z (accessioned)

2013 (issued)

degree

Health and Exercise Science (discipline)

10000-01-01 (liftdate)

embargo

forever (terms)

identifier

http://hdl.handle.net/10339/38532 (uri)

language

en (iso)

publisher

Wake Forest University

title

EXERCISE BLOOD PRESSURE IN ADOLESCENCE AND BLOOD PRESSURE FIVE YEARS LATER IN PERSONS BORN WITH VERY LOW BIRTH WEIGHT

type

Thesis