Are Sports Drinks Overhyped?

My patient was asking me what I fuel myself with for my weekly Saturday bike rides. He knows I usually ride between 80-100 km. He was shocked when I said that I only bring a banana and a bottle of water with a slice of lemon for taste. 

Perhaps he had been influenced by social media and advertisements, and felt that hydrogels, superstarch, theanine, isotonics and even coconut water packed with potassium were better for absorbing carbohydrates into our system while exercising.

SuperStarch?

Perhaps some of the latest choices mentioned earlier may give an extremely small edge. Do they perk you up in the morning, help you metabolize energy, increase your focus and 'protect' your body as they claim? Especially since none of them are solidly backed by research. Will you go and order the latest offerings? 

I've written before that sports drinks definitely cannot replace your sodium levels during exercise. What it can definitely do is to provide you with some carbohydrates for fuel during prolonged (longer than 90 minutes) exercise to sustain your level of performance.

Results suggest that sports drinks can fuel you to maintain athletic performance. In the article referenced below, the authors wanted to know if a pre-exercise meal affects sports drink effectiveness. The subjects (cyclists) rode 105 minutes at lactate threshold followed by a 10 km time trial under 4 conditions. No breakfast before the ride with a placebo sports drink. No breakfast with a real sports drink. Breakfast with a placebo sports drink and breakfast with a real sports drink.

The breakfast the riders had were consumed 3 hours before the exercise. It had 824 calories, consisting of two thirds conbohydrates. The real sports drink had 8 percent maltodextrin (works like glucose but has no taste) while the placebo was just artificially sweetened. The sports drink was consumed every 15 minutes during the first 105 minutes ride and halfway mark of the 10 km time trial. 

Those who had the real sports drink with breakfast managed 198 watts in the time trial, those without 197 watts, not much difference. Strangely enough the results did not give any boost to the cyclists who fasted (no breakfast). I would have thought that the sports drink would help those who did not eat breakfast, ride better. Other studies did find a difference. Using the real sports drink helped with or without breakfast. 

There was definitely a negative effect for those who skipped breakfast without the real sports drink. With breakfast but no sports drink the cyclists managed 173 watts, with no breakfast, no sports drink it was 154 watts. They also had the highest rate of perceived exertion.

Note that at the start of the time trial, those who had breakfast with placebo drinks kept up with those with breakfast and real sports drink. As the time trial progressed and fuel stores were used up, those without the real sports drink fell farther and farther behind since their placebo drink failed to fuel them. 

This study shows that consuming carbohydrates during prolonged exercise definitely makes a difference. What I liked about the study was that the subjects did not know if their sports drink was real or placebo. The time trial started only after 105 mins, long enough for carbohydrate stores to be depleted. There was also no funding (from the sports drinks industry) for this study, so less chance of any bias.

If you are out racing or training for a few hours or more, commercial sports drinks aren't the only option. Neither is hydrogel, superstarch or any of the latest offers. Many sports drink companies may advertise their specialized formulations, but the 3 basic ingredients needed are water, sugar and salt. Beyond these 3 ingredients the science gets a lot weaker. 

Many triathletes drink flat Coke (see picture below) in the Ironman events and eat bananas or dried figs. I'll usually just have a banana, dried raisins or dates. Just make sure you have something to suit your palate. Oh! And remember not to skip breakfast.

Reference

Leari SK, Ghiarone T, Silva-Cavalcante MD et al (2019). Cycling Time Trial Performance Is Improved By Carbohydrate Ingestion During Exercise Regardless Of A Fed Or Fasted State. Scan J Med Sci Sp. 29(5): 651-662 DOI: 10.1111/sms.13393.

You can the dark Coke stains on the front Mark Allen's top after beating Dave Scott after 6 attempts and finally winning at the 1989 Hawaii Ironman. 

*Picture taken from my book Ironwar by Mark Fitzgerald, Velopress 201.

Which Drink Hydrates You Best?

Ever wondered which drink is best after a hard training session or race? I've written before that as a recovery drink, chocolate milk is as effective as Gatorade and even superior to Endurox.

Quite a few factors affect how quickly you pee out a certain drink. Drinks with more calories or electrolytes tend to stay in your system longer. How much you drink at a time also plays a part according to an article I read.

Researchers recruited 73 subjects to test 13 different drinks. Each subject tested water and three other beverages. At each session, the subjects drank a litre of the chosen beverage and collected their urine for the next four hours.

A "beverage hydration index" showed how much of that drink was retained after two hours compared to a litre of water.

Picture from American Journal of Clinical Nutrition

Looking at the picture above, you can see that a higher bar means more fluid retained. The dotted line represents twice the coefficient of variation away from water (meaning you can be real sure of a positive result).

The chart shows that milk stays longer in the body probably because of its calorie content. Milk and an oral rehydration solution (or sports drink, due to its calories and sodium) also stays in your system.

Personally, I was quite surprised that tea, coffee and beer did not seem to produce significantly more urine.

In fact coffee seems to have the lowest reading in the chart. The authors suggested that the diuretic properties of alcohol may be counterbalanced by its retention promoting calories (although another previous study that compared regular and alcohol free beer showed that regular beer drinkers had 12 percent more urine).

The authors also pointed out that larger doses of caffeine or alcohol may trigger more urine

Well, now you know not all drinks take the same time to reach your bladder. Choose your drinks wisely after your hard training session or race.


Reference

Maughan RJ, Watson P et al (2016). A Randomized Trial To Asess The Potential Of Different Beverages To Affect Hydration Of Different Beverages To Affect Hydration Status: Development Of A Beverage Hydration Index. Am J Clin Nutr. 103(3): 717-723. DOI: 10.3945/ajcn.115.114769.

Sports Drinks Cannot Replace Your Sodium Levels During Exercise

Gatorade- thirst quencher, but can it replace your sodium levels?

Last week I wrote about what causes muscle cramps. I also said I will write about why the Sports drink/ fluid replacement companies are inaccurate in telling us that sports drinks like Gatorade, Powerade and Endurox etc can replace electrolyte losses.

When you sweat, your electrolyte levels begin to rise! Yes, you read correctly. Let me explain more.

Let's say you have five cups of water and five teaspoons of salt in your system. If you remove one cup of water and a teaspoon of salt, the balance remains the same. There is a teaspoon of salt for every cup of water (i.e. a concentration of 1.0).

Now if you lose 2 cups of water (like when you exercise) and a teaspoon of salt, you've lost more water than salt. The concentration of salt has now risen to 1.25. Your salt (and electrolyte) levels are now higher and will remain higher as you become more dehydrated.

Apply this concept to our physiology. Our sodium (salt) concentration of blood is about 140 mM (or 3.2 grams of salt in every litre of blood). Our sweat has a sodium concentration between 20-50 mM. So even for "salty sweaters" (people who lose more salt than others when they sweat), they lose about 1.1 grams of salt max in every litre of sweat.

Thus, the theory that muscle cramping is caused by low electrolytes as a result of sweating cannot be true. You definitely lose more fluid (or water) than sodium when you sweat.

Sports drinks are incapable of maintaining your body's sodium levels during exercise despite what the manufacturers and advertisers tell you. The sports drink industry has created a perception  that its electrolytes that will help prevent a decrease in sodium.

As explained above, sweating does not decrease your sodium levels, it causes an increase in sodium levels. Sports drinks actually contain insufficient sodium to counteract the effects of sweating on the blood's electrolyte concentration. In fact it causes your sodium levels to fall further.

A sports drink usually contains approximately 18mM of sodium (or 0.4 grams of sodium per litre). That means if you drink a litre of Gatorade (or 100 plus, Powerade etc) during exercise, you can replace a litre of fluid, but only 0.4 grams of sodium.

Blood normally has 1.4 grams of sodium per litre, so even a sports drink replaces more water relative to salt and will only lower your sodium concentration. You CANNOT elevate or even maintain your sodium levels by drinking a sports drink. It is impossible.

Of course if the alternative to sports drink is water, then sports drinks can help prevent sodium levels from falling further.

The key point is that a sports drink will still cause a decline in sodium levels, though less compared to water.

The act of drinking is what causes the reduction. To prevent your sodium levels for dropping further, you're better off not over drinking in the first place.

It's better to listen to your body and obey what it suggests you to do.

Now you know.

References

Science of Sport - Sports drinks, sweat and electrolytes Part 1

Science of Sport Muscle cramps Part IV

Dugas J (2006). Sodium Ingestion And Hyponatraemia: Sports Drinks Do Not Prevent A Fall In Serum Sodium Concentration During Exercise BJSM. 40: 377. DOI: 10.1136/bjsm.2005.022400.

Sports drinks we have in Singapore

If I have to, I prefer Pocari- "tastiest" to me

Chocolate Milk, Gatorade or Endurox

I don't know about you but for me, I'll choose chocolate milk every single time. Plus you know what, my choice happens to be backed by scientific research.

Allow me tell you more. I've often been asked by friends, patients and even my competitors what I eat/ drink for my recovery after a hard training session or race. I'll tel them usually I'll eat/ drink whatever I fancy or whatever I find in the fridge at home. Most of the time it's an ice cold Coke and/or chocolates, chocolate milk, chips etc. I always get an incredulous look from my friends especially." Are you allowed to do that?" Well, the study below actually says I may be right. Well, ( I don't know about Coca Cola or chips), but with regards to chocolate milk anyway.

Published in the International Journal of Sport Nutrition and Exercise Metabolism, Karp et al, 2006 found that chocolate milk was an effective recovery aid, similar to Gatorade and superior to the more expensive Endurox. For athletes training twice per day, chocolate milk is an effective recovery aid. Plus they taste a lot better to me than Gatorade or Endurox anytime.

Reference

Karp JR, Johnston JD et al. (2006). Chocolate Milk As A Post-exercise Recovery Aid. Int J Sport Nutr Ex Metab. Feb; 16(1): 78-91.

We drink Oat milk now, not cow milk