Effect of leg immersion in mild warm carbonated water on skin and muscle blood flow

Leg immersion in carbonated water improves endothelial-mediated vasodilator function and decreases arterial stiffness but the mechanism underlying this effect remains poorly defined. We hypothesized that carbonated water immersion increases muscle blood flow. To test this hypothesis, 10 men (age 21 ± 0 years; mean ± SD) underwent lower leg immersion in tap or carbonated water at 38°C. We evaluated gastrocnemius muscle oxyhemoglobin concentration and tissue oxygenation index using near-infrared spectroscopy, skin blood flow by laser Doppler flowmetry, and popliteal artery (PA) blood flow by duplex ultrasound. Immersion in carbonated, but not tap water elevated PA (from 38 ± 14 to 83 ± 31 mL/min; P < 0.001) and skin blood flow (by 779 ± 312%, P < 0.001). In contrast, lower leg immersion elevated oxyhemoglobin concentration and tissue oxygenation index with no effect of carbonation (P = 0.529 and P = 0.495). In addition, the change in PA blood flow in response to immersion in carbonated water correlated with those of skin blood flow (P = 0.005) but not oxyhemoglobin concentration (P = 0.765) and tissue oxygenation index (P = 0.136) while no relations was found for tap water immersion. These findings indicate that water carbonation has minimal effect on muscle blood flow. Furthermore, PA blood flow increases in response to lower leg immersion in carbonated water likely due to a large increase in skin blood flow.

Effects of Sulfate-Rich Mineral Water on Functional Constipation: A Double-Blind, Randomized, Placebo-Controlled Study

BACKGROUND

Magnesium sulfate has a long tradition as a laxative. It osmotically prevents water absorption in the large bowel and thus leads to an acceleration of the intestinal transit and better stool consistency. We wanted to investigate the efficacy of a carbonated calcium/magnesium sulfate-rich natural mineral water in subjects with functional constipation (FC).

PATIENTS AND METHODS

In this double-blind, randomized, placebo-controlled study, subjects with FC (Rome III criteria) received 1 l/day (4 × 250 ml) of mineral water (Ensinger Schiller Quelle) or carbonated tap water (placebo) for 6 weeks. The primary endpoint was the change in the frequency of bowel movements per week between baseline and visit 4 (after 6 weeks). The prespecified main secondary endpoint was the change in the frequency of bowel movements per week between baseline and visit 3 (after 3 weeks).

RESULTS

Efficacy was analyzed in 100 subjects (intention-to-treat). After 6 weeks of treatment there was no statistical difference between the groups (p = 0.163). However, statistical significance was reached after 3 weeks, with an increase in the frequency of bowel movements per week of 2.02 ± 2.22 for the mineral water group compared to 0.88 ± 1.67 for the placebo group (p = 0.005).

CONCLUSIONS

A 3-week treatment with 1 l/day of the sulfate-rich mineral water improved the frequency of bowel movements in subjects with FC compared with tap water; however, the difference was no longer significant after 6 weeks. Further evaluation in rigorously designed clinical studies will be necessary to validate the impact of sulfate-rich natural mineral water on FC.