Associations of Resting Hemodynamics with DXA Total Body Fat Percentage in Collegiate Rugby Union Athletes

Elevated adiposity is linked to cardiometabolic risk, yet relationships between total body fat and resting hemodynamics are not well described in collegiate rugby populations. PURPOSE: Examine associations between DXA total body fat percentage (%fat) and resting heart rate (HR) and blood pressure (BP) in male rugby union athletes. METHODS: Twenty-one male rugby union athletes completed same-morning testing (06:00–09:00 h) following ≥12 h fast and post-void, with stimulants (including caffeine) restricted ≥12 h and no exercise ≥24 h. Hydration was screened using urine specific gravity (USG; CLINITEK Status+ with Multistix 10 SG) and urine color (clear yellow). After 5-min seated rest (legs uncrossed; dominant arm supported at heart level on a table), manual brachial SBP/DBP were measured once using a Welch Allyn DS66 Trigger Aneroid (cuff sized by arm circumference) and resting HR assessed via radial pulse palpation and recorded in the seca assessment record. Whole-body DXA was performed on a Hologic Horizon W (APEX v5.6.1.3 Rev 007; standard tissue analysis; daily QC within tolerance) to derive total %fat. Mean arterial pressure (MAP) was calculated as DBP + (SBP−DBP)/3. Pearson correlations were computed between %fat and HR, SBP, DBP, and MAP; secondary analyses compared HR across %fat tertiles. RESULTS: Total %fat was 22.2 ± 8.0%. HR, SBP, DBP, and MAP were 65.5 ± 9.2 bpm, 117.8 ± 9.3 mmHg, 74.9 ± 6.4 mmHg, and 89.2 ± 6.5 mmHg, respectively. %fat was positively associated with HR (r=0.45, p=0.039) but not SBP (r=0.27, p=0.230), DBP (r=0.19, p=0.418), or MAP (r=0.25, p=0.269). HR differed across %fat tertiles (Low: 58.9±9.7; Mid: 68.0±8.3; High: 69.7±6.0 bpm; p=0.049). CONCLUSION: In collegiate rugby union athletes tested under standardized conditions, higher DXA-derived total %fat is associated with higher resting HR, whereas resting BP indices show no clear association. These findings suggest adiposity-related autonomic differences may be detectable even when resting BP remains within typical ranges.