I’ve been getting A LOT of questions lately about sodium and hyponatremia, so I wrote something up on the subject:
Hyponatremia, a drop in sodium levels, can occur due to the loss of sodium and chloride during extreme sweating (sodium, chloride, and water are the major components of sweat). Usually, when you sweat, you also lose plasma volume due to the loss of water, but some people consume a lot of water without salt. This causes the plasma plasma osmolarity (basically, ratio of solutes to fluid in the plasma) to increase even further. When plasma osmolarity decreases it will actually cause more water to be excreted by the kidneys (meaning you are peeing it out) in an attempt to maintain plasma osmolarity. The problem is that this signals your brain that you are thirsty, meaning you will continue to take in water despite the fact that you don’t actually need it. And you kidneys can only excrete so much at one time.
So what? Well, when plasma osmolarity is too low, it can cause your cells to swell to the point of bursting. Your brain can swell, causing the CNS symptoms seen in hyponatremia. I’m sure you all know brain swelling is bad, but you may not realize that it can cause a coma and even death. Furthermore, sodium is an essential ion for things like muscle contraction. Basically, you can’t just replace sweat with water for a long period of time. Your body can’t make it’s own sodium, so it needs salt. Salt can be found in sports drinks, gels, and salt pills. Or in a salt shaker.
Questions? I TA’ed Human Physiology for two years before going for my PhD in the subject, so I’m happy to try to answer any random phys question you might have for me (and yes, I do know what makes it light vs dark meat, you wouldn’t believe how often I’ve gotten that question).
Sorry for the short post, but I’m exhausted and need to go to bed early. And I want to finish my incredibly strange book (Bumped by Megan McCafferty). Also, Rufus ate half a cardboard box, so I suspect we have some serious poop coming on. Tomorrow I will post my 7 links if I survive my 7 mile run in the blazin’ heat. Good thing there is a new FroYo place opening up down the street tomorrow! 50% for grand opening means I am there!
Any exciting weekend plans? Seriously, hit me with your phys questions, I’m a giant nerd, so I love researching them.