At present, there are about 100 elements known. The human body uses around 27 of these. The most abundant is oxygen, which makes up approximately 63% of the body's mass. Carbon comprises 18%, hydrogen 9%, and nitrogen 3%. These four are the key elements in body's most important molecules: water, proteins, lipids, carbohydrates, and nucleic acids.
Continue Reading » What are the Major Elements and Molecules in the Human Body?
If you wait until you are thirsty it is too late. You are already dehydrated. You ever heard that? I'll bet you have. Right before you were told to pour a gallon or two of water down your throat every single day. Complete and utter bull-hockey.
Continue Reading » Why Waiting Until You Are Thirsty Is NOT Too Late
Hyponatremia is an electrolyte imbalance in which the sodium concentration in blood plasma falls lower than normal. It has been believed, for many years that we "lose" salt through our sweat.
This is why our high school track coach encouraged us to take salt pills. Hyponatremia is also what sports drinks are supposed to prevent. As far as most coaches were concerned back then, we were losing salt by the gram as soon as we started sweating.
Continue Reading » Do Sports Drinks Prevent Hyponatremia?
In the last article we introduced you to Randy, our imaginary 70 kg average male runner, and we created some potential scenarios regarding his fluid and sodium losses and replacement. The biggest take home message was to listen to your body and to drink to thirst, as this has been shown again and again in the field and the lab to keep people from drinking either too little or too much. We have received tons of feedback and discussion, and as we stated in the comments to that post we are pleased that so many of you are participating in the discussion, sharing your stories, and asking relevant and insightful questions.
Continue Reading » Muscle Cramps Part V
This is a pseudo-Part V of our series on Muscle Cramps - I was tempted to call it Part V, but it's a little bit of a departure from what we've been talking about. In our next article, which we will be calling Part V, we'll wrap up this really challenging series and try to summarize all of the comments and our articles into one concluding piece.
Continue Reading » Muscle Cramps Part 4.5
Over the past three articles, we've taken what has turned out to be a pretty intense look at muscle cramps. We began with a discussion of how muscle cramps were first attributed to a low serum electrolyte concentration, without any substantial evidence for this theory. We then moved on to show that, in fact, people who cramped have the SAME electrolyte concentrations and levels of dehydration as those who do not cramp - this is pretty strongly suggestive that cramping is not caused by either dehydration or electrolyte depletion. Then in Part III, we described a new model for muscle cramps, involving a 'malfunction' in the reflex control of muscles during fatigue.
Theories and Fallacies of Muscle Cramps Part III: A Novel Theory for Exercise-associated Muscle Cramps
This marks the the third part of our series on muscle cramps. It was going to be the final installment in this particular series, but we've received some excellent and thoughtful questions and comments on the issue, so have decided that we'll do a fourth article, just summarizing some of those key "sticking" points. It seems from the feedback that this issue - electrolytes and cramps - is one of the more contentious ones around. So in our FOURTH article of the series, we'll look back and try to tie up any loose ends and conceptual issues.
This is a follow-on from our series of articles on Fluid Intake and Dehydration, and as we were preparing to write this series, we realized that there may actually be even more nonsense and blatant lies in the media than there were for dehydration!
Continue Reading » Theories and Fallacies of Muscle Cramps Part I
So far we investigated the history of fluid ingestion in Part I, demonstrated why it is the metabolic rate that predicts temperature in Part II, and weighed up the strengths and weaknesses of the lab-based and field studies in Part III. For Part IV we will look at the thirst mechanism and why waiting until you are thirsty is not "too late."
Continue Reading » Fluid Intake, Dehydration, And Exercise Part IV
Welcome back for Part III in this series on fluid intake and dehydration during exercise! Thus far we have examined a brief history of fluid replacement during endurance exercise in Article I, and in Article II we tried to explain how some of the lab research has perhaps been over-interpreted, and how that has lead to a false belief that ingesting fluid during exercise will keep you cool. In that article we reported the findings of earlier researchers who concluded the following:
* The core temperature is maintained at a higher level during exercise
* It is the metabolic rate (or in other words, how hard you are exercising) that predicts the core temperature
Continue Reading » Fluid Intake Dehydration And Exercise Part III
This is the second article in our series on fluid intake, dehydration and exercise. In the last article we looked at the history of fluid intake and how radically our beliefs on the subject had changed. Today we turn our attention to the evidence that has accompanied this shift, beginning with the contention that runners who become dehydrated are likely to develop heat stroke.
Continue Reading » Fluid Intake Dehydration And Exercise Part II
The story begins, as most do, at the beginning…a look at the history of fluid intake and drinking during endurance exercise, which serves to illustrate an important point, one which will be covered again and again in this series…For this post, we acknowledge Professor Tim Noakes of UCT, the fluid pioneer whose lifelong pursuit of the truth in this area (and a lone battle for much of it) has thrown up the excellent quotes and anecdotes we use as we delve into the issue.
Continue Reading » Fluid Intake, Dehydration, and Exercise Part I