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 70-90 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.

Sip it or Gulp it?

Gulp it

If you have been exercising continuously for over an hour, you know that you have to refuel at some point. Especially if you are participating in a race. Carbohydrate refuelling during a race or a long training session can definitely enhance your exercise performance since there is a limited store of glycogen (carbohydrates) in your liver.

Sip it

The amount of carbohydrates (carbs) in the stomach is one of the main factors that would determine the speed of gastric emptying. A larger volume will empty faster than a smaller volume.*

However, a large volume of carbs in the stomach is not ideal for runners. How many of you runners reading this can drink large volumes of fluid (or eat lots of energy gels) during races and endure the fluids sloshing around in your stomach and intestines? 

When I was still competing in triathlons, I always took small sips while running past the feed stations. I would mostly eat/ drink on the bike leg of the triathlon as it does tend to sit better in my stomach since there is less movement while I'm cycling. 

However, a study I read studied whether ingesting carohydrate sports drinks during prolonged running affects exogenous carbohydrate oxidation (sparing liver glycogen, and yet maintain exercise intensity)  and gastrointestinal discomfort. This means that your glycogen stores are not being used as quickly during exercise since whatever you are drinking is being used to fuel your exercise.

The runners studied did two, 100 minutes of steady state runs at moderate intensity. In the first run, the runners consumed 200mL every 20 min while they took 50 mL every 5 min during the second run.

The researchers found that exogenous carbohydrate oxidation rates were 23 percent higher during exercise when larger volumes were ingested every 20 minutes. They concluded that ingesting larger volumes would be better than frequently sipping small amounts since large volumes will stimulate gastric emptying and makes more carbs available for intestinal absorption.

More importantly, there was no difference in gastrointestinal problems whether a larger or smaller amount was ingested while running. The authors indicated that this was also similar to what was observed in earlier studies. They suggested that runners may be able to tolerate more fluids than they think they can during exercise.

Those who are still competing should try and practice ingesting more carhohydrate gels/ drinks in training to make sure you do not get any stomach upsets. This will train your gut to absorb more carbs and help you race faster.

Reference

Mears SA, Boxer B, Sheldon D et al (2020). Sports Drink Intake Pattern Affects Exogenous Carbohydrate Oxidation During Running. Med Sci Sports Ex. 52(9): 1976-1982. DOI: 10.1249/MSS.0000000000002334

*This topic has been well studied and recommendations are to consume 30-60 g/hr for exercise/ events lasting between 1 to 2.5 hours. For exercise/ events over 2.5 hours, up to 90g/ hr should be consumed. If more than 60g/ hr needs to be ingested, a combination of carbohydrates (e.g. glucose and fructose) needs to be ingested. 

Here's how I fold the paper cup to sip while running

You Definitely Do Not Need Extra Sodium Supplementation, Not Even In Hot Conditions

A few weeks ago I wrote about why it is not necessary to consume sodium to prevent muscle cramps. That post was popular as many runners shared it.

Well, here's further proof and confirmation that you do not have to consume sodium, even in a long ultra marathon.

Researchers found that majority of ultra runners (66 percent) in a race feel that sodium supplements should be made available at aid stations to prevent hyponatremia  and muscle cramping.

Previous research shows that consuming extra sodium does not prevent cramps, dehydration or nausea. Findings actually show that excessive sodium consumption can lead to the extra sodium left as residue on your skin and clothes. This is commonly seen as a white deposit left on your skin especially after a long training session or race.

After you consume too much sodium, it may lead to drinking too much water causing hyponatremia. Trust me here, as I'm guilty of this actually. I spent 2 days in the intensive care unit of a Hong Kong hospital when I had hyponatremia during a 100 km race in November 2000.

The researchers also found that a typical race diet (sports drinks, gels and bars) will usually provide enough sodium for your needs. Moreover sodium itself is not a source of fuel that can help sustain your efforts.

The researchers concluded that that study showed that no sodium supplements are required for ultra marathons in hot conditions lasting 15 to 30 hours (Hoffman et al 2015).


References

Hoffman MD et al (2015). Sodium intake During An Ultramarathon Does Not Prevent Muscle Cramping, Dehydration, Hyponatremia, Or Nausea. Sp Med Open. 1(1): 39.


Hoffman MD  and White MD (2019). Belief In The Need For Sosium Supplementation During Ultramarathons Remains Strong: Findings From The Ultrarunners Longitudinal Tracking (ULTRA) Study. Appl Physiol Metab. DOI: 10.1139/apnm-2019-0238.

How To Beat Muscle Cramps? Sunday Times Article

Sunday Times article 280719

Today's Sunday Times article on training for the Straits Times run says avoid muscle cramps by consuming more sodium? Nah, not totally true. Not at all actually. I've written about this exact same topic way back in 2015.

In that post, I wrote about how renown sports scientist Tim Noakes found no significant differences in sodium and magnesium levels in 72 ultra marathoners among those who cramped and those who did not cramp (Schwellnus et al, 2004). They found that sweating too much had no real effect on muscle cramps.

Try to think of when you last had a muscle cramp? After running 30 km in your marathon or after 3 km in a 10 km race?

Muscular fatigue (or when your muscles get too tired) is what really causes muscle cramps. The muscle cramps so you can avoid injury before you can push yourself further. That the Sunday Times article definitely got correct.  

Muscle cramping occurs mostly during races than during training. If you started your race too fast or you pushed too hard, that may cause your muscle to fatigue and then cramp. Other studies have shown that tough, hilly courses and poor pacing are predictive of muscle cramps.

I also wrote that sports drinks cannot replace your sodium levels during exercise. Your electrolyte levels actually rise when you sweat a lot. Yes, you read correctly. I'll explain this below.

Assume you have five cups of water and five teaspoons of salt/ electrolytes in your body. Say you sweat 2 cups of water and a teaspoon of salt/ electrolytes when you exercise, the concentration of salt/ electrolytes is now higher. It will remain higher as you become more dehydrated.

Apply this concept to our running physiology. Our sodium (salt) concentration 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. Even for a "salty sweater" (those who lose more salt than others when they sweat), they lose about 1.1 grams of salt max in every litre of sweat.

Hence, the theory that muscle cramping is caused by low electrolytes/ salt as a result of sweating is not true. You will definitely lose more water than sodium when you sweat. You can read more of that here.

You read it here first. Now you definitely know.

References

Science of Sport Muscle Cramps Part IV

Science of Sport - Sports Drinks, sweat and electrolytes Part I

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.

Schwellnus MP, Nichol J, Laubscher T and Noakes T (2004). Serum Electrolyte Concentrations And Hydration Status Are Not Associated With Exercise Associated Muscle Cramping (EAMC) In Distance Runners. BJSM. 38: 488-492. DOI: 10.1136/bjsm.2003.007021.

*The Sunday Times article is on page A27 under the Sports section. Go take a look.

Going Bananas?

Ready to go riding with my bananas

I've written before that sports drinks cannot  totally replace your electrolyte losses during exercise. Moreover, sports drinks are manufactured and may contain flavorings and chemicals that you may want to avoid.

And if you're like me and prefer eating real food and drinking lemon water (or just plain water) rather than sports drinks while exercising, then you may be doing enough to replace the carbohydrates to fuel your exercise and even speed recovery.

A preliminary study in 2012 found that cyclists performed better for a strenuous bike ride if they had a banana or sports drink compared to water. The cyclists also had lower levels of inflammation after the ride. That study did not show why and how the carbs were aiding recovery.

The same authors did a new study that was recently published using more sophisticated techniques to track molecular changes inside the cyclist's bodies.

The subjects' underwent a intense 75 km bike ride inside the laboratory. In one ride, they drank only water while in another ride, they had water, eight ounces of a sports drink or half a "Dole" banana every 30 minutes.

The subjects' blood was tested before during and immediately the ride and even 45 hours after the ride. Inflammatory blood markers and metabolites were assessed during and after to test how much stress was taken by them.

When the cyclists' drank only water during the ride, relatively high levels of inflammatory markers were found. These same markers were much lower if the cyclists' had consumed the banana or sports drinks. Metabolite profiles were less stressed regardless of whether they had the banana or sports drink compared to without.

One obvious difference was those cyclists' that ate the bananas had blood cells that produced less COX-2 (a genetic precursor of an enzyme). This was not seen if they drank only water or had the sports drink.

For those interested, COX-2 enzyme stimulates prostaglandin production, which increases the intensity of inflammation. Those of you who take inflammatory medication like Arcoxia or Celebrex tablets note that they are COX-2 inhibitors. They help reduce inflammation.

This study suggest that bananas might perform comparably although it is unknown how bananas affect the cells' gene expression. So instead of popping pills like Arcoxia and Celebrex prescribed to you, you may want to eat more bananas and ginger.

It was calculated by the researches that half a standard banana provided similar carbohydrates as a cup of sports drink and the cyclists' had half every 30 mins. Bear in mind your needs may be different. Some cyclists' also complained of feeling bloated after eating that amount of bananas.

So be warned before you go bananas over ingesting bananas in your next long ride or race.


References

Nieman DC, Gillitt ND et al (2012). Bananas As An Energy Source During Exercise: A Metabolomics Approach. PlosOne. DOI:10.1371/journal.pone.0037479

Nieman DC, Gillitt ND et al (2018). Metabolic Recovery From Heavy Exertion Following Banana Compared To Sugar Beverage Or Water Only Ingestion: A Randomized, Crossover Trial. PlosOne. DOI:10.1371/journal.pone.0194843

*Note that Dole Foods which sells bananas funded both studies. However, they company did not have any involvement in study design, data collection, analysis, decision to publish or preparing the article.

Today's Straits Times Article On Hydration

Straits Times article 160917 page C13 under Sport section

Every morning when I pick up the newspapers, I'll usually turn to the sports section first. Today, I happened to look at the article on the training plan for those planning to run the Singapore marathon at the end of the year. "Right hydration integral to a successful race". I thought the article was well written. Fairly straight forward and simple to understand. Also mentioned that over drinking water can lead to hyponatremia.

Wrote about sports drinks. Though you need to know that sports drinks cannot replace or even maintain your sodium levels during exercise or racing.

Just wanted to point out that the two percent loss of body weight (through sweating) during endurance exercise/ racing affecting your performance may not be totally accurate.

I wrote about it before earlier in the year that latest published research suggest that current hydration guidelines may well be wrong.

Two published studies on cyclists and elite male marathoners (including Haile Gabreselassie during 13 major city marathons) showed that weight loss up to three percent did not slow the runners down nor decreased the cyclist's power output.

In fact Gabreselassie lost 9.8 percent of his body weight during the 2009 Dubai marathon and still won the race in 2:05:29 hours! All drinking by the elite runners were ad libitm (or at their own time and pleasure).

Yes I do agree that the quoted study was done on elite runners. How does that apply to us in super humid and sunny Singapore?

My own thoughts are that the sports drink companies definitely recommend us to drink to much. I wrote before that I definitely drink less than my fellow team mates and competitors. From the time I started running cross country as a twelve year old kid to when I was racing triathlons. Even now during my weekly group bike ride. Most of the other cyclists carry two or more water bottles while I survive the three hour ride on one.

In fact I often had a side stitch after drinking while running cross country as a kid. That also deterred me from drinking too much then.

Of course this does not mean you try not to drink at all in your next long run/ ride and especially your next race. What I'm suggesting is that you at least give it a try in your next few long bike or run sessions.  Everyone is different. Try to get through those long sessions drinking as little as you can. You might be pleasantly surprised that you may not need as much fluid as you think.



References

Beis LY, Wright-Whyte M, et al (2012). Drinking Behaviours Of Elite Male Runners During Marathon Competition. Clin J Sport Med. 22(3): 254-261. DOI: 10.1097/JSM.0b013e31824a55d7.

Wall BA, Watson G et al (2015). Current Hydration Guidelines Are Erroneus: Dehydration Does Not Impair Performance In The Heat. BJSM. 49(16): 1077-1083. http://dx.doi.org/10.1136bjsports-2013-092417.

Current Hydration Guidelines May Well Be Wrong

Picture by richseow from Flickr

We've been told in the past by articles, journals and research scientists that if you lose more than 2 percent of your body weight (through sweating) during endurance exercise/ racing your performance will be affected.

Moreover, advertisements from Sports drinks companies keep harping on the fact the you need to drink up or else you get dehydrated.

However, some recent studies (as well as anecdotal evidence from the world's top distance runners) suggest that it may be possible to lose more than 2 percent of your body weight (from sweating) with little or no loss in your performance.

Research scientists from New Zealand's High Performance department have suggested that previous published dehydration studies were conducted in "relatively windless environments (i.e. wind speed less than 12.9km/h) with participants being aware their hydration status." They stated that such conditions do not simulate real race conditions.

In their own (albeit) small study of 10 cyclists, they found that weight loss of up to 3 percent did not slow down the cyclists nor their power output decrease in a 25 km time trial.

Another study on elite male marathoners examined their drinking behavior during 13 major city marathons. Haile Gebreselassie was found to have lost 9.8 percent (and that's a lot) of his body weight during the 2009 Dubai Marathon and still won in 2:05:29 hrs. All drinking by the elite runners were ad libitum (or at their own time and pleasure).

Granted the above study was done on elite runners. Does that even apply to mere mortals like us? Especially in hot and super humid Singapore.

Here are my own thoughts. From the time I started running cross country as a twelve year old kid, I've noticed that I tend to drink less than my team mates and other competitors. And definitely less than what the Sports drinks companies recommend. In fact I often had a side stitch after drinking. That also deterred me from drinking too much then.

So despite what you've heard or read before, at least give it a try in your next few long bike or run sessions. Try to get through those long sessions drinking as little as you can. You'll be pleasantly surprised that you may not need as much fluid as you think.

References

Beis LY, Wright-Whyte M, et al (2012). Drinking Behaviours Of Elite Male Runners During Marathon Competition. Clin J Sport Med. 22(3): 254-261. DOI: 10.1097/JSM.0b013e31824a55d7.

Wall BA, Watson G et al (2015). Current Hydration Guidelines Are Erroneus: Dehydration Does Not Impair Performance In The Heat. BJSM. 49(16): 1077-1083. http://dx.doi.org/10.1136bjsports-2013-092417.