Cardiovascular and metabolic responses to tap water ingestion in young humans: does the water temperature matter?

Abstract

a M. Girona and E. K. Grasser contributed equally to this work.Abstract Aim: Drinking water induces short-term cardiovascular and metabolic changes. These effects are considered to be triggered by gastric distension and osmotic factors, but little is known about the influence of water temperature. Methods: We determined, in a randomized crossover study, the acute cardiovascular and metabolic responses to 500 mL of tap water at 3°C (cold), 22°C (room) and 37°C (body) in 12 young humans to ascertain an effect of water temperature. We measured continuous beat-to-beat haemodynamics, skin blood flux with laser-Doppler flowmetry and resting energy expenditure by indirect calorimetry starting with a 30-min baseline followed by a 4-min drink period and a subsequent 90-min post-drink observation. Results: Ingestion of cold-and room-tempered water led to decreased heart rate (P < 0.01) and double product (P < 0.01), and increased stroke volume (P < 0.05); these effects were not observed with body-tempered water. Drinking cold-and room-, but not body-tempered water, led to increased high frequency power of heart rate variability (P < 0.05) and baroreflex sensitivity (P < 0.05). Cold-and room-tempered water increased energy expenditure over 90 min by 2.9% (P < 0.05) and 2.3% (ns), respectively, accompanied by a diminished skin blood flux (P < 0.01), thereby suggesting that both small increases in heat production together with decreased heat loss contribute to warming up the ingested water to intra-abdominal temperature levels. Conclusions: Overall, ingestion of cold-and room-, but not body-tempered water reduced the workload to the heart through a reduction in heart rate and double product which could be mediated by an augmented cardiac vagal tone.

Cardiovascular responses to sugary drinks in humans: galactose presents milder cardiac effects than glucose or fructose

“…In these latter studies, glucose led to marginal or no increase in BP similar to that observed in the present studies after glucose and galactose. Moreover, based upon our previous observations [16,21] that SBP tended to increase by a few mmHg over 1-2 h after a 0.5 L water load, our findings here of a small gradual increase in BP after glucose or galactose ingestion could be largely attributed to the water-load component of the sugar drinks rather than an effect of these sugars per se. Overall, in previous studies from our laboratory [16,17] and in the present study, the BP response to fructose was found to be significantly greater than that after glucose by 3-4 mmHg.…”

“…A Task Force Monitor (CNSystems, Medizintechnik, Graz, Austria) was used to perform cardiovascular recordings, and data were sampled at a rate of 1000 Hz [21]. Continuous BP was monitored using the Penaz principle from either the index or middle finger (automatically finger switch every 30 min) of the right hand and was calibrated to oscillometric brachial BP measurements on the contralateral arm.…”

Comparative effects of glucose and water drinks on blood pressure and cardiac function in older subjects with and without postprandial hypotension

“…(2014) reported that the effect of water ingestion on cardiac function in healthy young individuals is also dependent on its temperature; ingestion of water at 30°C and 22°C increased SV, whereas water at 37°C did not (Girona et al. 2014). Recently, Grobety et al.…”

Cardiovascular and cutaneous responses to the combination of alcohol and soft drinks: the way to orthostatic intolerance?

“…The probe of the LDF was set on the dorsum of the left hand between the thumb and the index finger as described previously (Girona et al, 2014), with a withinsubject variability for the baseline period between the drinks to be about 23% estimated from our previous study (Girona et al, 2014). However, rather than comparing baseline across separate days, we were interested to monitor overall changes from baseline during the same session, with inherently less variability.…”