Question on Sports Drinks

I just received a great question from a coach about what he should tell the athletes he coaches about sodium and protein in sports drinks during long events such as Ironman. Here is my reply...

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I’ve been doing a lot of reading in the literature and talking with informed people regarding, especially, sodium. I’m coming to the conclusion that sodium is not necessary during exercise for all of the reasons we have previously been told were so critical - cramping, coping with heat, and maintaining pace/power. I can find no good evidence to support any of these. Just a lot of opinions and sports drink marketing stuff (which most athletes have come to accept as factual).

That said, sodium is beneficial in the transport of water across the intestinal mucosa in the upper intestine where it is absorbed. In other words, with a bit of sodium in the drink you get more water into the body. That may be beneficial to performance if there is a real risk of excessive dehydration (which is far too often blamed for poor performance). As I’ve mentioned before, the most dehydrated athlete in the race is typically the winner. But this is a whole other discussion.

Is protein necessary or even beneficial in a sports drink? The research is murky on this still. However, there is something called “central fatigue” which has to do with the central nervous system experiencing the need for sleep during extended exercise. This seems to be related to circulatory branched chain amino acid status. A couple of studies have suggested that taking in protein during or before exercise may prevent this. But the condition seems to be quite rare. Interestingly I spoke with an athlete a few days ago who did an Ironman and felt like he just wanted to lay down beside the road while in the bike leg and take a nap. This may have well been central fatigue.

What do I do? I eat well before starting a workout. Then I drink water only when thirsty on very long rides and carry carb products such as gels and bars in my pockets. They have a small amount of sodium and negligible protein. Water-only works fine for the first two hours on long, easy to moderately hard rides for me. Then I start taking in carbs along with the water. For example, last week I rode over 500 miles in the Colorado mountains with thousands of feet of moderately hard climbing every day. The average duration was nearly 5.5 hours a day for 6 days. I did just what is described above and never experienced the least bit of problems.

But that was an n=1. Individual athletes may well have unique needs I don’t have for any number of reasons. Some experimentation (with an open mind) is necessary to discover what works. The problem is that most athletes have been so inundated with marketing hype (much of it from “science”) that they can no longer think critically.

I tell the athletes I coach that if they want to use sodium during exercise that’s alright. I know of no downsides (although there may well be some we don’t know about yet such as balancing potassium and sodium, and inter- vs intracellular fluid levels). The same goes for protein. It’s up to them if it has worked ok in the past. If they have had digestive tract problems such as nausea or the gut “shutting down” then I suggest omitting the protein.

Generally, I have come to believe that we need far less “stuff” in our guts during exercise than we have come to believe over the last 30 years. The only two things that seem to stand the test of time are water and carbohydrate. And it’s quite possible to be excessive with both of these.

I hope this helps a bit. I wish I could tell you without question that what I’m suggesting here is irrefutable. It’s where my head is right now on this subject. Time marches on.