Interview with Dr. Tim Podlogar: Isotonic Sports Drinks

Isotonic sports drinks are one of the first supplements every dedicated cyclist needs, but they differ greatly in terms of quality and efficiency.

Luckily, we sat down with dr. Tim Podlogar to shed some light on what's going on.

Tim, we know you're very busy with your scientific work and the role as a nutritionist in a professional cycling team, not to mention your own cycling endeavors. Thank you for taking the time to talk to us.

No problem. I'm always happy to share some of my knowledge with your athletes.

Today we'd like to discuss isotonic sports drinks. Why are they so important?

Carbohydrates are a source of energy, the other two being protein and fat. Of course, during exercise, carbohydrates are the most important.

But carbohydrate stores in the body are limited. Once they run out, we hit the wall, i.e. run out of energy. 

To sustain high-intensity exercise, we must intake carbohydrates. Many athletes make the mistake and start intaking them only once they start feeling fatigue — it's too late then. 

You must intake carbohydrates from the beginning, as this is the only way to slow down glycogen consumption.

Many athletes still don't understand the role of carbohydrates during exercise. How does poor carbohydrate availability really affect their performance?

Many athletes mistakenly believe that they can perform at their best until they run out of energy, but that's not how it works.

If carbohydrates are not available, the consequences are felt immediately.

One of them is increased muscle catabolism, i.e. the breaking down of muscle tissue. I'm sure nobody wants that.

Muscle cramps are also a common consequence of poor carbohydrate availability.

Another thing to suffer is muscle recovery. If you want to train the next day, you're doing yourself a huge disservice if you neglect your carbohydrate intake.

Ok, we get it, carbohydrates are a must during exercise. But what quantity are we talking about?

It all depends on the number of watts a cyclist is able to produce during physical activity. Basically, it comes down to exercise intensity and fitness level.

For most recreational cyclists, anywhere from 40 to 60 grams per hour should suffice.

But advanced cyclists, and definitely professionals, should consume up to 90 grams per hour.

Unfortunately, such a high intake often leads to one of the most common problems with isotonic sports drinks — digestive issues.

The bane of all endurance athletes. Are there any other issues with isotonic sports drinks?

Having worked with countless endurance athletes, isotonic sports drinks mainly have three problems — low energy efficiency, muscle cramps, and digestive issues.

Ironically, digestive issues are the consequence of athletes trying to prevent the first two problems. To have energy and prevent muscle cramps, you need to intake more carbs, but intaking large amounts of wrong carbs leads to digestive issues. It's a vicious circle.

A vicious circle indeed. But has there been any progress in terms of resolving these issues?

Isotonic sports drinks are nothing new, really. But in terms of improvement over time, I see a lot of silly moves being made by manufacturers — they might improve the packaging or add magic ingredients, such as coconut water or cinnamon (I'm not kidding).

The flavors change, the names change, fruit gets five different adjectives, and many add magnesium as the ultimate tool to prevent muscle cramps.

To boost sales, marketing teams use established faces to push their products.

And yet, manufacturers keep failing at solving the main problems of isotonic sports drinks, leaving many athletes unhappy with their fueling products.

Were you one of these athletes?

Yes.

It lead me to the point where I realized that I needed to take matters into my own hands.

That's how I partnered up with Nduranz — it was a brand that shared my vision to create the best possible supplements for endurance athletes.

The result of our collaboration is the Nrgy product line, among them Nrgy Drink 45, Nrgy Drink 90, and Nrgy Gel 45.

How did Nduranz solve these issues?

The main factor is the carbohydrate ratio.

Years ago, prof. Asker Jeukendrup at the University of Birmingham was the first to discover that consuming only glucose caps absorption at 60 grams per hour. Once they added fructose, absorption rates rose, leading to great improvement in fueling efficiency.

They determined the best ratio between glucose and fructose was 2:1, although this ratio was determined seemingly at random and had no scientific support.

Many brands still use this ratio as the optimal carbohydrate ratio.

But it's not the ratio Nduranz chose for their products — why not?

Since the beginning, I advocated for the 1:0.8 glucose-to-fructose ratio.

Later on, the studies of prof. David Rowlands from New Zealand confirmed that my assumption was correct. I was happy to see that Nduranz believed in me and used this ratio in all of their fueling products.

Considering the feedback of athletes, both amateur and professional, they made the right choice, as this ratio turned out to be highly efficient both in terms of energy availability as well as preventing digestive issues.

What makes the combination of glucose and fructose so effective?

Most carbohydrates you can buy in a store contain only glucose — bread, pasta, rice, maltodextrin, it's all glucose. Fructose is rare, found in variable amounts in fruit and honey.

The main factor is that glucose and fructose utilize two different carbohydrate transporters in the body. This increases absorption rates from 60 grams per hour for glucose only to 90 grams per hour.

Another factor is that fructose must first be transported to the liver before being transformed into glucose or lactate. For this reason, it had been probably avoided as a source of energy, but as it turns out, this actually improves energy efficiency.

But isn't fructose considered to be harmful to our health and a cause of fatty liver?

That's a long story.

Yes, it could happen. But only if you consume large amounts of fructose while physically inactive. On the contrary, for an endurance athlete during high-intensity exercise, fructose is not only harmless but also very beneficial.

Very interesting. But isotonic sports drinks are not just about carbohydrates, are they?

No, they are not. Another important factor is hydration.

There seem to be many misconceptions regarding proper hydration. Could you explain how it really works?

Sure.

Hydration is all about preserving the electrolyte balance in the body.

For an athlete, there are three focal areas: the drink or supplement they use, blood, and sweat. Most research focuses on the blood, but for an athlete, the most important is sweat — we need to replace the electrolytes lost with sweat.

By sweating during physical activity, we lose primarily water and salt.

If we were to intake only water, the concentration of sodium (salt) would decrease, leading to problems. On the other hand, if we intake too much sodium, this leads to stomach issues and a strong sensation of thirst.

Ok, hydration is important, we get it. Any other issues we should know about?

As a matter of fact, yes.

Electrolytes affect the volume of cells. If we increase the concentration of sodium, water from cells, including muscle cells, will enter into the bloodstream. This happens when we are dehydrated and is not good news for the body functions.

On the other hand, if the concentration of sodium in the blood starts decreasing, water will enter the cells, and the cells will begin to swell. This wouldn't be the end of the world if it weren't for an organ called brain. Inside the skull, brain cells have little space to expand, which causes them to pop. This is called hyponatremia, and at the worst, it can cause death.

That's grim. But probably it doesn't happen very often, right?

Unfortunately, it's more common than you'd think.

You sure know how to make a point. What about magnesium? You mentioned earlier it is a common inclusion in many isotonic sports drink.

The thing is that many athletes still believe that magnesium prevents muscle cramps, and the manufacturers gladly support that claim.

If you ask me, that's nonsense. As a matter of fact, when we are dehydrated, the concentration of electrolytes in the blood increases. This means their availability is higher and not lower.

There is also no research to confirm the link between muscle cramps and the electrolyte intake.

The only way electrolytes could be a factor in the occurrence of muscle cramps is if we were to drink only water, diluting the concentration of electrolytes in the blood.

Not to mention that magnesium is very often another cause of digestive issues, especially when consumed in large amounts.

That's very interesting. If magnesium is not the way, how can we then avoid muscle cramps?

Let me first explain what a muscle cramp is.

It is an involuntary muscle contraction that doesn't allow us to relax the muscle. The only way to relax it is by stretching it, thus deactivating the activation of nervous fiber in the problem muscle.

We can see it's a type of error in the transport of nervous signals that has nothing to do with an electrolyte imbalance — you can't affect the electrolyte balance by stretching, can you?

Generally speaking, muscle cramps occur during heavy efforts, in hot environments, or at the end of physical activity. All this is linked to low energy availability, namely carbohydrates, and partly with muscle micro-tears.

In simple terms, muscle cramps occur when the intensity of our physical activity exceeds our capabilities.

So, if we understand correctly, the best way to prevent muscle cramps is by consuming a sufficient amount of carbohydrates?

That's correct.

Tim, thank you for your time.

You're welcome.