The sport drink industry is a massive one. Estimated at nearly $7 billion in 2012 (and it was growing), the industry preys in part on the notion that because our sweat is salty, we need to replace it, and to replace it quickly.
But do we?
A study published way back in 1991 tried to answer that question.
The researchers took 8 cyclists and ran them through 6 gruelling hours of intermittent cycling in an 86°F room of 50% humidity, and kept their intensities at 55% of their VO2 Max. Each cyclist repeated this exercise 3 times on 3 separate occasions and 3 separate conditions. Once with no water or sports drink, the next time with just water, and lastly with just a sports drink where in both the water and sports drink treatments both were provided in quantities sufficient to replenish their volume of losses to sweat. The cyclists would cycle for 13 minutes, and then take a 2 minute break during which their heart rate, rectal temperature, and their perceived exertion were measured. Blood was drawn at the 15 minute mark and at hours 2, 3, 4, 5, and 6 to measure plasma sodium and plasma aldosterone.
The results were striking and easy to describe.
Simply put, if the study is to be believed:
1. You don’t need to hydrate yourself at all during non-dramatic bouts of exercise. Certainly if you’re thirsty, that’s your sign to drink, but if you’re not thirsty, probably no need. In this experiment’s case, when drinking nothing, these cyclists DID have to stop the experiment short, but only after a long 4.5 hours of cycling (where the experiment was stopped short due to a marked rise in core temperature, heart rate and perceived exertion).
2. Unless you’re exercising vigorously for longer than 6 hours straight, you don’t need a sport drink to replenish your “electrolytes“, because in this study, there was no difference in plasma sodium levels between the water drinkers and the electrolyte drinkers even after 6 hours of heavy-duty exercise!
I asked my friend Alex Hutchinson, author of the fantastic Which Came First Cardio or Weights his thoughts on the matter and he put it rather succinctly,
“electrolytes are irrelevant in the vast majority of situations“.
So definitely don’t ignore your body’s cues and do drink to satisfy any thirst you might have when you’re exercising, but if your exercise isn’t extreme and it’s less than 6 hours in duration, you probably need never “replenish” your electrolytes.
[And just as a reminder of what’s in most sport drinks, below is my homemade Powerade video from a few years ago]
A few weeks ago I had the great pleasure of delivering the keynote address for Physical Health and Education Canada’s annual national conference.
The title of my talk was “Rebranding Exercise” and it makes the case for detaching exercise from weight loss and reattaching it to health.
As to why exercise needs to be rebranded? By preventing cancers, improving blood pressure, cholesterol and sugar, bolstering sleep, attention, energy and mood, and doing so much more, exercise has indisputably proven itself to be the world’s best drug – better than any pharmaceutical product any physician could ever prescribe. Sadly though, exercise is not a weight loss drug, and so long as we continue to push exercise primarily (and sadly sometimes exclusively) in the name of preventing or treating adult or childhood obesity, we’ll also continue to short-change the public about the genuinely incredible health benefits of exercise, and simultaneously misinform them about the realities of long term weight management.
Video’s below where you’ll also find links to every journal article I mention in the talk listed in order of appearance. The first 28 minutes has me covering the evidence with as much animation as standing behind a podium allows, but if you just want to see me get fired up and explain why rebranding exercise is important, skip ahead to the 28 minute mark where I extricate myself from the clutches of the podium and watch from there.
Huge thanks to PHE Canada and Doug Gleddie for the invite and to Brent Gibson from PHE Canada for recording and posting the talk.
On April 8th, an editorial was published in the British Journal of Sports Medicine (published by the BMJ). The editorial had to do with the fact that exercise doesn’t seem to help much with weight loss and consequently, we should probably stop tying the two together – and it’s an opinion I share.
But today I’m not blogging about the editorial or about exercise, but rather what happened next.
Shortly after the article was published, it was removed following, “an expression of concern“.
A few weeks later and the article’s back up, and according to the journal, the concern had to do with two undeclared conflicts of interest. One author did not disclose that he is a paid advisor to Atkins, and another did not disclose that he wrote a diet book.
Curiously, on March 13th, just 3 weeks prior to the publication of this piece, another editorial, this one positing that in fact it is a lack of exercise that is driving obesity, was published by the very same British Journal of Sports Medicine.
That piece, authored by Steven Blair, Gregory Hand, and James Hill, have no author declarations of conflict whatsoever (though it does point out that the organization the editorial is announcing was funded by Coca-Cola). Yet Blair and Hill together have authored 21 books on the importance of exercise, and a quick Google search for both certainly reveal very close relationships with Coca-Cola (including this recent $2.5 million grant from Coca-Cola to Blair and Hand on the very subject of their editorial), along with a bevy of board appointments to organizations whose interests would be benefited by interest in “energy balance“.
Leaving me to wonder three things:
1. Who submitted the “expression of concern” to the BMJ?
2. Should the BMJ be doing a better job exploring authors’ conflicts before publication?
3. Are these sorts of conflicts important to disclose?
by Saeed Khan If you work on a product that requires a training class, your product is way too complex!!! OK, just kidding. If you work in the B2B space, it’s almost guaranteed that there is a training requirement for your product. The training may be delivered face-to-face in a classroom setting, or over the […]
Social networks, the term has come to mean more than one thing in our society. And this particular study can really throw you for a loop if you focus on what most of us now think of when we say […]