SPEAKER: Hi, everyone. My presentation today is looking at drinking water. Now we know that water is a vital nutrient for human life, but exactly how much of it do we need to drink? Well, today I'm going to review some of the research.
So, for example, there's a common idea that we should drink eight glasses of water every day. But researchers say that the eight glasses a day rule is a myth. Some people might need more than eight glasses, some a lot less. The only group for whom the rule is useful seems to be the 1elderly because they don't always feel thirsty even when their bodies are actually short of water. So for them, eight glasses a day might be a good rough guide.
Okay, let's look next at what effects water has on the body. One issue of interest is weight loss, and there are lots of theories about this. It's been claimed that dieters should drink more at nighttime or drink when they first wake up, but there's no research to back this up, but actually there is some evidence from studies to show that subjects who drank a lot of water and then have their 2meals, lost more weight. But that may only be because the water filled them up and reduced their appetites.
I also read some of the research done by Dr. Amaldi, who's looked in depth at this whole issue of drinking water, and one of his studies does support the common claim that water is good for the stomach. In particular, it seems to increase the rate at which 3digestion takes place, which overall has a number of health benefits.
Another interesting study I read about took place in the US, and this one was investigating the effects of dehydration. That is not having enough water in the body. And what the US study indicated was that when a subject was low on water, their body's ability to regulate its own 4temperature was compromised, compared to a properly hydrated subject.
Now there's another frequent claim about water that I was interested in looking into, but in my reading anyway, I could find no evidence at all to support the idea that hydration improves or enhances the 5skin in any specific way, so that claim may be a bit of a myth as well.
Another interesting aspect of this concerns the brain, and I read about a couple of research studies investigating how water intake may affect brain function. In the first study, the research subjects were female and the less hydrated group were affected more frequently by 6headaches compared to those who drank more water.
In the second study, the research subjects were all male and this time a lack of water in the body was associated with a number of findings. In particular, the subjects in this group reported increased feelings of 7anxiety when dehydrated.
So, in summary, we can see that, yes, there are some health benefits from drinking plenty of water. But in many of these studies, the benefit was quite small. And it's probably true that in general, on the Internet and so on, the benefits of drinking lots of water are overstated.
But what about the opposite? Can you drink too much water? Well, it's possible, but it's not a common problem. Actually, the human body cannot prevent us from drinking too much. Australian researchers discovered that when subjects were fully hydrated, they actually found 8swallowing problematic. Their bodies just wouldn't allow it so easily. So that's an interesting finding.
It is true that people do occasionally become sick from drinking too much water, although it is rare. So I mean, there are recorded instances of illness among 9athletes who have been encouraged to drink a lot, for example.
According to doctors people who have drunk too much water too quickly have become what's called hyponatremic. Basically, this means that the makeup of their blood has changed and it now contains such a high proportion of 10salt that they suffer an adverse effect. But it's very rare for this sort of hyponatremia to be a dangerous condition.
So based on the reading I've done, the best advice is to trust your body. Drink water when you're thirsty, but you probably don't need to drink more often than that.
