Essay: Water is more effective at rehydrating than electrolyte drinks

One: In the first graph, the trend lines show that over 90 minutes, the volume of urine in both the control and chips groups decline by about 75% on average (112  30 mL in control group). However, the groups that ingested electrolytes and water saw a slight spike in the volume of their urine over the 90 minutes (95  117 mL in the water group). Moreover, the colour of urine sees a decline in both the electrolyte and water groups, while staying relatively steady in the control group, and seeing an slight increase in the chips group.
What this information tells us is that due to the electrolytes present in both the water and the Gatorade, the subject is becoming increasingly hydrated, thusly expelling more urine, and the remaining urine that is expelled is much lighter in colour. The combination of both a greater volume, and lighter colour of urine indicates a high level of hydration within the subjects. Consequently, they are producing around 4 times as much urine as the control group at the 90 minute mark (30 mL vs. 108/117 mL). Moreover, the increasingly darker colour present as well as, on average, having the lowest output volume of urine indicates dehydration within these subjects. Comparatively, the control subjects also suffer from slight dehydration with a much lower volume of urine being produced at 90 minutes, however still producing around 5mL more than those who have consumed a high level of sodium in the chips.
In each group, the most drastic changes are present at around the 30 minute mark. Each group experienced a significant drop of in the volume of the urine produced. However, at the 60 minute mark, both the electrolyte and water group experience a significant spike in their produced volume, whereas the control group experiences only a slight increase, and the chips group sees a steady decline throughout the next final stages. This indicates to me at between 30-60 minutes, the electrolytes and fluid within the Gatorade and Water have worked their way through the body to rehydrate it, thus producing more urine.
Two: Anti-diuretic hormone (ADH) is a hormone released by the posterior lobe of the pituitary gland into the bloodstream with the purpose of controlling blood pressure, and conserving the volume of fluid in the body by regulating the amount of water passed out in the urine (Society for Endocrinology 2015). In the occurrence of a high sodium intake, ADH works to retain water from the urine, transport it back to the blood stream, and consequently dilute the increased concentration of sodium in the body (Society for Endocrinology 2015) . Therefore, one can determine that due to the decreased volume of urine excreted by the subjects of the chips group, as well as the increased osmolality of the urine, a certain level of water has been retained within the body due to the increased levels of ADH, caused by the increased sodium intake of the subjects.
Atrial natriuretic peptide (ANP) is a cardiac hormone (synthesized and secreted by cardiac muscle cells) which works to regulate electrolyte homeostasis and well as regulate blood pressure (Clinique Marc-Linquette 1999) . ANP works against aldosterone as ANP increases renal sodium loss and aldosterone increases renal sodium retention (Dr Bruce Forciea 2015). ANP is secreted in response to the stretching of the atrial walls due to increased blood volume (Clinique Marc-Linquette 1999). Consequently, it targets the kidneys in order to decrease sodium reabsorption, overtly increasing the amount of sodium, as well as water leaving the body by osmosis (Dr Bruce Forciea 2015). ANP is secreted in the group which consumes the electrolyte drink due to the increased level of both sodium and water the body is receiving via the drink, thus cause ANP production to re-regulate the level of sodium and water in the body via increased urine volume. Another effect is decreased osmolality of the urine.
Finally, aldosterone is a steroid hormone excreted by the adrenal glands with the purpose of increasing retention of sodium and water within the body and increasing the amount of potassium in the urine by activating a receptor in the cytoplasm of renal tubular cells (Encyclopaedia Britannica 2018). Due to the lack of sodium increased in the water group, the body responds by retaining the sodium within the body in order to keep it at a balanced level through the production of aldosterone. Consequently, a higher level of potassium is excreted within the urine in order to rid the body of any risen levels due to the intake of water, returning the body to homeostasis.
Three: Homeostasis refers to the stable equilibrium maintained by physiological processes in the body between interdependent elements. Its purpose is to ensure that the body maintains a regulated balance of many variables such as temperature, sodium/water concentration and food intake, in order to promote effective bodily functioning. The body effectively responds to all the stimuli provided by the various substances in order to maintain homeostasis. For example, if the body retains too high of a level of sodium within the body results in and increased blood pressure and water retention, causes an increased strain on the cardio-vascular system.
As shown by the results of the experiment, it is evident that the actions of each of both ANP and aldosterone start to occur between 30-60 minutes, however the effects of ADH are more evident between he 0-30 minute time frame. This is evident due to the spikes in volume of urine in both the electrolyte and water group, and the greatest decrease of urine volume in the chip group over the respective time periods. Similarly, these effects are shown in the largest decrease in osmolality of the urine in the electrolyte and water group between the 30 and 60 minute marks and the most significant increase in urine osmolality being shown between 0-30 minutes.
Four: I believe there were multiple ways to improve the accuracy of the data in this experiment. However slightly unrealistic, a way to improve accuracy overall would be to sample an even larger randomised group. Not only this, but it would have been interesting to see is the results would have differed when taking samples from a larger age bracket, not just late teens/early 20s. Moreover, it would have been more effective to much more closely monitor each subject’s timing, I know that multiple students were un-phased by the timing of their sampling as well as some making estimations as opposed to accurately measuring and recording their results. Further, if the experiment was to be repeated once a week over a series of at least 3 weeks, the data would have become increasingly accurate as opposed to a one-off test.
Conclusion:
Based on the evidence provided in this experiment I would argue against the recommendation of the electrolyte drink as an everyday drink. I would argue this based on the results of this experiment, showing that over a 90 minute period, water in fact did a more effective job of rehydrating the body. Not only did it start at a lower average volume at 0 minutes, it ended up causing the subjects to produce an even higher volume of urine at the end of the 90 minutes, after reaching a lower point at the 30 minute mark. Not only this, but the subjects hydrated by water also produced, on average, a lower average colour of urine at every stage of the test, showing that they were in fact more effectively hydrated. Consequently, I would argue that electrolyte drinks such as Gatorade are less effectively in actively rehydrating a non-exercising body.
Reflection:
Upon conducting this experiment I felt rather hesitant. It was evident to me that the entire cohort was feeling rather uncomfortable and confused about the practical component of this experiment. While some thought it was strange, I just felt it a little uncomfortable to collect and study my own urine. When I went to conduct the first leg of the experiment (0 minutes) I felt incredibly uncomfortable and found it quite hard to urinate because of this. However, after the first leg I found it got increasingly easier and I found it very interesting to track my quantitative results throughout the 90 minutes.
Further, this experience taught me that conduction scientific research, especially when studying physiological systems, can be quite invasive even though what is being conducted is completely natural. Moreover, it became increasingly evident that elements of human error (i.e. being unable to accurate collect urine, effecting the volume recorded) as well as conducting a valid experiment proved difficult due to the fact that students were either unfocused or unwilling to conduct the requirements of the experiments as accurately as possible, effecting the overall results of the experiment.
What I did enjoy, was the act of physically doing the experiment. As a kinaesthetic learner, I found it incredibly helpful to actively participate in an experiment. This way, I was able to be interested about my own results, making my own predictions about what my result at each time slot would be as well as being able to more accurately recall the information that I was recording. I much prefer this learning style to simple reading or listening, as the physical action of doing the experiment assists me in understanding the results as well as the process involved in the experiment.