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Effects of Sodium Loading plus Walking on Bone Mineral Content (BMC)
Author(s) -
Angelakos Kailyn,
HewButler Tamara
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.lb765
Subject(s) - urine , placebo , medicine , treadmill , sodium , zoology , urology , chemistry , pathology , organic chemistry , alternative medicine , biology
Determine if sodium loading and changes (Δ) in blood sodium concentration ([Na + ]) are related to Δ's in BMC after walking. Methods 2 single‐blind randomized trials: 6 flour tablets (P: placebo trial) or 6 1g‐NaCl tablets (S: salt trial). Tablets ingested after baseline blood and urine collection. Dual energy x‐ray absorptiometry (DXA) scan performed next. After 60 minutes of rest, a 45‐minute treadmill walk was conducted. Immediately post‐exercise, blood and urine were collected. DXA scan repeated. Main outcomes included pre‐ to post‐exercise changes (Δ) in blood [Na + ], urine [Na + ], and BMC. Results 14 subjects completed both trials. Significant increases (S vs. P trial, respectively) noted in: post‐exercise blood [Na + ] (144±2 vs.140±2mEq/L; p<0.0001) and urine [Na + ] (115±53 vs. 64±46 mEq/L; p=0.01); Δ blood [Na + ] (3±2m; vs. 0±1mEq/L; p=0.0001) and Δ urine [Na + ] (21±36 vs. ‐15±28mEq/L; p=0.006). Significant differences in BMC seen in Δ left rib (‐5.4±7 vs. 0.2±6g; p=0.03), which corresponded to location of ingested tablets pre‐exercise, and Δ total body BMC (‐5.5±27 vs. 14.1±21.4g; p=0.04). Δ blood [Na + ] positively correlated with Δ urine [Na + ] (r=0.47;p=0.01) and Δ thirst rating (r=0.49; p=0.008). Δ total BMC negatively correlated with: post‐exercise blood [Na + ] (r=‐0.43;p=0.02); Δ blood [Na + ] (r=‐0.43; p=0.02); and Δ urine [Na + ] (r=‐0.47; p=0.01) and positively correlated with Δ left leg BMC (r=0.54;p=0.003) and Δ right leg BMC (r=0.53; p=0.004). Conclusion :1) increases in blood and urine [Na + ] associated with decreases in total BMC; 2) Δ total BMC linearly related to Δ's in left and right leg BMC after treadmill walking; 3) Reductions in left rib and total BMC closely approximate NaCl ingested (~6g; inactive) before dissolution into bloodstream (active), suggesting localized sensitivity of DXA to NaCl tablets.