Should you put a smart water bottle on your holiday wish list?
The other day I was in an Apple store, perusing the accessory shelves for holiday gift possibilities, when a tall box containing something that appeared to be a water bottle caught my eye. Upon closer inspection, the object actually was a water bottle. A smart water bottle. Ah, of course.
The HidrateSpark 3 pairs with an app, so you can see how much more water you need to reach your daily goal. “Glowing reminders and text notifications keep you on track… map your progress daily, weekly and monthly,” according to the HidrateSpark website.
We often hear that we should “stay hydrated” and “drink 8-10 glasses of water a day.” You may be wondering where this recommendation comes from. Women need 2 to 2.5 liters of water per day, which is 2000 to 2500 milliliters (ml)/day. Men need 2.5 to 3 liters, or 2500 to 3000 ml/day. An 8-oz glass of water contains 240 ml of fluid, so drinking ten 8-oz glasses of water in one day would provide 2400 ml. Simple. But this overlooks two important things.
While the total recommended intake for adults may be 2 or 3 liters of water daily, this is water from all sources of intake. Anything liquid (coffee, tea, milk, juice, smoothies, soup, kombucha, etc) is mostly water and can be considered equivalent. And foods that you eat may also contain a lot of water. People naturally think of watermelon (47% water) as a watery food, but cucumber and lettuce are much higher, at 96%, and a hard boiled egg is surprisingly high at 75%. On the low end, crackers and most nuts are 3 to 5 % water.
A study published in 2016 of total fluid intake in Europe (France and the UK) using food and beverage diaries did show that most adults were somewhat under-hydrated, and this might be even worse in the USA, where the average diet contains relatively little food moisture (an estimated 19%, vs 40% in China). But before you reach for your wallet (the HidrateSpark costs $59.95), consider this. Your body already possesses a finely tuned sensor mechanism, involving receptors, hormones, and nerve pathways that result in a feeling of thirst if water intake is too low. You can also use your eyes: look for light-colored urine. If you are producing small amounts of concentrated or dark urine, you need to drink more water.
People who have had kidney stones do need to drink more, and this is a category of people who may benefit from a smart water bottle, especially if they have trouble remembering. In fact, there is a study in progress that will evaluate whether using the HidrateSpark will prevent kidney stones in patients who have already had them. (It’s possible that having a smart water bottle won’t make any difference though. We’ll have to wait until 2021, the study completion date, to find out). Older people also can lose their ability to feel thirsty and may need assistance in remembering to drink (but I cannot imagine my 82-year-old mother pairing anything to a smart phone).
For most people, drinking 1-2 glasses of water or fluids with each meal (assuming 3 meals a day) and not ignoring feelings of thirst, is enough. Increase your intake of fruits and vegetables, which will lead to better general health as well. And if you want to buy a water bottle, consider an unconnected one (easier on the environment and your pocketbook). Wirecutter has done the research for you here.
References
Guelinckx, I., et al: Contribution of Food and Fluids to Total Water Intake: Analysis of French and UK Population Surveys. Nutrients. 2016 Oct; 8(10): 630.
Institute of Medicine, Food and Nutrition Board . Dietary Reference Intakes for Water, Potassium, Sodium, Chloride and Sulfate. National Academies Press; Washington, DC, USA: 2004.
Zhang Q., Hu X., Zou S., Zou J., Pan Q., Liu C., Pan H., Ma G. Water intake of adults in four cities of China in summer. Chin. J. Prev. Med. 2011;45:677–682.