Showers are always a good time for making lists. I don’t mean mundane lists such as what do I need from the grocery store, or whose birthday have I forgotten? But really important lists. This morning as I was having my shower, the list I was formulating was singers who only go by one name. Without much thought I came up with Prince, then Sting. Of course, female singers are equally represented by Sade, Cher and Adelle. Being a scientist, my mind wandered to think of the great scientists who are also known by one name, including Galileo, Newton, Curie, Einstein, Franklin. If one name is cool, then surely multiple names are cooler, which brought to mind Theophrastus Philippus Aureolus Bombastus von Hohenheim. One of the things old Theo said was that “the dose makes the poison”. Have enough of anything and it will kill you. Since I was finishing my shower, my thoughts naturally turned to how much water would you need to drink before you die. Against a background of being encouraged to drink water, at least 8 glasses a day according to some sources, how much is too much?
In January 2007, Sacramento California morning radio show “The Rave” lured contestants to their studios to drink huge amounts of water without going to the bathroom. The prize? A Nintendo Wii video gaming system. Jennifer Strange, a wife and mother of three, from Rancho Cordova, decided she was going to win the Wii for her family. One of 18 contestants in the “Hold you wee for a Wii” contest, Jennifer and the others were asked to drink as much water as they could without going to the bathroom. As the Morning Rave program started at around 6:15 a.m., the contestants were each given eight-ounce bottles of water to drink every 15 minutes. Fellow contestant James Ybarra noted “They were small little half-pint bottles, so we thought it was going to be easy”, but after 90 minutes and five bottles, Ybarra quit citing “My bladder can’t handle it anymore”. The remaining contestants continued on, being asked to drink even larger bottles of water to stay in the competition. As the competition neared its end, Strange had consumed nearly two gallons of water in just over three hours. Throughout the contest, Strange could be heard complaining about pain to the show hosts.
Although the contestants and the show hosts seemed oblivious to the potential danger, the radio audience was not, with several callers, including a nurse stating that people drinking so much water in such a short time could get sick from water intoxication. The show hosts replied that they were “aware of that”, but since the contestants signed a release the hosts were not responsible.
One of the disc jockey hosts did ask the question “Can you get water poisoning and, like die?”
“Not with water” another host rejoined, “Your body is 98% water. Why can’t you take in as much water as you want?”
“Maybe we should have researched this before” the female host quipped.
In the end Strange did not win the contest, but was given a consolation prize of tickets to an upcoming Justin Timberlake concert.
Water intoxication (or water poisoning, or hyponatraemia), happens when you drink more water that your kidneys can get rid of through urine, especially if you are trying not to urinate. But its not just the amount of water you drink, its how quickly you drink the water that also counts. You’re at greater risk of water intoxication if you drink a lot of water in a short period of time. The risk is considerably less if you drink the same amount of water over a longer period of time, with frequent urination. Symptoms of water intoxication can occur from as little as a gallon (3-4 litres) of water in a short amount of time. Although our kidneys can eliminate 5 – 7 gallons (20-28 litres) of water a day, they can’t get rid of more than about 30 ounces (1 litre) of water an hour. So on average you should avoid drinking more that 30 ounces of water per hour on average. But why is so much water so bad? Well it all has to do with the salt levels in our blood, particularly the amount of sodium. When you drink a lot of water in a small amount of time, the sodium in the blood becomes very dilute, much more dilute than the sodium concentration in our cells, especially the cells in the brain. Because of this imbalance in sodium concentrations, lots of water leaves the blood and enters our cells, causing them to swell. Many tissues can cope with some swelling, but because brain cells are encased in the rigid bone of our skulls, they have nowhere to swell, other than getting squished against the inside of the skull. When the brain tissues get damaged like this, all the functions controlled by the brain, including breathing, are severely compromised. It shouldn’t take much thought to realize this is not a good idea!
As Jennifer Strange drove home, she was not feeling well. She had planned on going into work after the contest, but that was not going to happen, she had to get home and lie down and rest. Shortly after Jennifer got home, she was dead. Following a law suit against the radio station, a jury awarded Strange’s family $16.5 million compensation for wrongful death. The disc jockey hosts were also released from their jobs.
How much water should you drink? The Institute of Medicine suggests 125 ounces for men and 91 ounces for women, however these recommendations also include water found in food. Some people follow the eight 8-ounce glasses a day, though this is not really based on any rigid scientific research. A good rule of thumb is drink when you’re thirsty. This should be good enough, though athletes, older adults and pregnant women may require more.
Dr Neil Bradbury 