Resting Blood Pressure in Collegiate Swimmers During a Competitive Season: A Prospective Observational Study.

Introduction The purpose of this study was to describe and examine differences in resting blood pressure (BP) during an eight-week time frame in the course of the competitive season among collegiate swimmers of varied sexes. Methods A prospective observational study using a sample of convenience of National Collegiate Athletic Association (NCAA) Division 1 female and male swimmers from one university were invited to participate. Blood pressure was measured using standardized methodology at six encounters spaced over eight weeks. Descriptive statistics analyzed demographics, mean BP, and BP classifications. A pairwise t-test analyzed differences in the mean BP and BP classification by sex. The Bonferroni correction was applied given the multiple variables included in the analysis with statistical significance determined to be p≤0.002. Results Thirty-eight swimmers (15 males and 23 females) met the inclusion criteria. Differences between sexes were identified with a higher mean diastolic BP observed in males at the third encounter (p=0.0004) and a higher mean systolic BP observed in males at the sixth encounter (p=0.0002). Four males and four females were identified with a BP classified as stage 1 or 2 hypertension at the first encounter; however, six males and no females met this criterion at the last encounter which was statistically significant (p=0.0004). Conclusions Increased BP from baseline measured for systole, diastole, and BP classifications was significant in male compared to female swimmers. Specifically, divergence in BP by sex first appeared in the diastolic measures at three weeks and in the systolic measures and BP classifications by eight weeks.