You exercise, you sweat. It’s a fact of life. Cycling indoors though makes you sweat even harder, and than can have a big impact on an athlete you don’t replace your salts carefully with sports electrolyte drinks
Sports Electrolyte Drinks – Replace Your Zwift Sweat
Sports electrolyte drinks and hydration generally is vital to effective training, even more so in the indoor environment. Whilst Zwift is amazing. It’s indoors. As a result you are are going to SWEAT BUCKETS. But serious sweating, when not accompanied by the right electrolyte replacement can leave you underperforming at best, and in danger at the worst. Read on for some of the science of hydration for indoor cycling!
Hydration for indoor cycling
When I do physical exertion to any major degree, I sweat. When indoors I sweat even more. Whilst that might be an issue for cycling cave gadgets, as I highlighted in the Wahoo KICKR Climb review, sweating a lot can also cause me issues as a rider
Actually, that’s not fair – I don’t sweat a lot. I sweat like I’m a leaking hosepipe!
Believe it or not one group who has a very similar issue with electrolytes is the elderly. Due to medications which patients which high blood pressure are often, but not always taking, they can have an issue with electrolytes. often low levels of salts, specifically sodium. This can cause light headedness, lassitude, nausea, vomiting, headaches, irritability, cramps, low mood. All of the things we can see in athletes “overdoing it”… or possibly under doing their electrolyte replacement
Warning Science sports post here!
So based on this experience, the sweat pools around my Elite Direto when on Zwift, and in conjunction with some work I’m doing at the medical school I’m going to look at staying hydrated. When I say staying hydrated, I don’t just mean pushing water into your face, but also maintaining the correct levels of electrolytes/salts to keep you and your muscles functioning at maximum performance.
Its only when you you have actually started to do frequent sessions of cycling indoors that you realise the true value of a turbo trainer mat. Its got, in my opinion, nothing to do with sounds deadening, and everything to do with making it easier to clean up the mess afterwards! It was seeing the pools of sweat from me, coupled with the recent increase in century rides being posted on the Zwift groups, that made me think it might be worth while finishing this article – I started the attempt about a month ago, but there is a lot of background reading that was needed
Some riders have gone it ingenious lengths to help cool down – none more so than Marc Atthecorner on the Zwift riders group, has appears to have a pain cave set up inside a wind tunnel!
Whilst most people can’t afford that sort of setup, many do use fans like the Wahoo HEADWIND to try and cool off whilst riding indoors. The problem is whilst the screen might have your rider bouncing up a snowy Alpe d’ Zwift, your sweat isn’t really working to cool down your respiring muscles. So you sweat more. In a cycle which has no benefit to the rider, as often the fan isn’t moving enough air to help them cool down
To reiterate, sweat has one purpose and that is to cool you down. The process is very elegant, you make sweat, and it takes heat away from your body in order to evaporate it. Simples. But if you go indoors, on a static trainer, without a fan, the sweat doesn’t evaporate well, but your body keeps on pumping out the sweat and the heat. The result is a big pool – so big in fact that an intense ONE HOUR session outside
Suddenly checking the back of the packet on your preferred sports electrolyte drink becomes a little more important
Even if you have the fan/jet engines pointed straight at you, over an hour you can still squeeze out over 2 LITRES of sweat. If you don’t believe me, or want to see how much you actually use, rather than collecting the sweat in buckets – both difficult and messy – weigh yourself before doing an event. Record your total fluid intake during the exercise and re-weigh yourself afterwards. Essentially 1litre of water is 1kg. The difference might surprise you!
Cycling gadget manufacturers are recognising how important hydration and nutrition – well certainly replacing losses – are to riders. As such the new Garmin Edge 830 builds on previous reminders to drink, by estimating your fluid loss over a ride.
Before a 55.5km Zwift ride with the TNW Early
The crucial point though is that these are NOT small volumes of fluid and must to be replaced. If doing longer rides, then they need to be carefully and continually replaced across the ride, which is often what you see during large cycling events with team cars
Even with the amount of sweat I produce, it’s unlikely that I’m going to be at any major risk of hyponatraemia – a lack of sodium in the blood as mentioned earlier – after one ride. BUT with the numbers of people doing 3-5 hour turbo trainer sessions regularly, multiple centuries and
It’s important to note that this is not a purely theoretical issue either – to put the issue into context, 10-15% of marathon runners upon crossing the finish line are found to have hyponatraemia – and each year there are many
Sports electrolyte drinks – Balance is key
But someone is always going to turn round and say – “I drink plenty of fluids when I’m on the bike/running/training, I just use regular juices etc I’m fine.” For a short hot ride, that’s ok, but when you are doing serious distances/durations, and producing a lot of sweat, all drinks are not made equally. One of the reasons why this is important is due to how your guts work and are affected when trying to replace fluids during an event.
The main reason for this post is to look at when you are not able to replace enough of the electrolytes you are loosing in the sweat. One of the signs of low sodium, hyponatraemia is a loss of appetite
All about the sodium
After an hour or two the turbo, I dont really feel like eating a meal for about an hour after. One of the reason for this may be post exercise, put there is also the possibility of a temporary dip in sodium levels. Even though I’m drinking on the bike, the electrolytes might not be getting into my system in time with the loss, hence the feeling off for a little after the ride.
The main reason for this is going to be just because the food has gone in your mouth, doesn’t mean it has actually entered your body. Remember that whilst we think eating is putting something into our body, the physiology doesn’t quite work like that.
You see, we, and all
Many sports drinks have higher concentrations of salts/solutes than the blood does. If you consume a sports drinks with more salt in it than your blood (hypertonic drinks like Gatorade), it slows the rate that the stomach empties, so again, you take in food and drink, but it just sits there. Remember there is little to no absorption done in the stomach, that all happens later in the intestines.
You can also have too much! So spending time on a turbo, drinking sports drinks and energy bars with too higher a concentration of electrolyte will give you the special joy of stomach cramps mid-ride. You’ll likely end up with leg cramps too as the salts are not really getting into your blood fast enough to even out the losses you are sweating out over your turbo. Sport companies try to get round this problem by making isotonic sports drinks which have the same level of salts as your blood
SIS market their energy gels as being isotonic, so allowing easier absorption and not slowing the gut – BTW, this isn’t advertising for SIS merely information I’m aware of. If you want to balance things out, personally, I’m not a fan for SiS due to the inclusion of sweeteners and the taste
Does sodium really matter than much?
So far I’ve basically said that if you drink too dilute/excessively concentrated sports electrolyte drinks, the sodium doesn’t get replaced. But why does this really matter? Yes, people have died from hyponatraemia in the past, but let’s be fair those are rare cases. There are however a raft of other symptoms which can suggest you are not replacing enough salt – and these will matter as they will affect your performance on the bike/run.
– Fatigue – we’ve all been in the situation of training heavily over several days, and just not had the get-up and go, but pair this is muscle weakness, and it might indicate you need to up your intake of salts off the bike. Personally, I’ve found a power meter (whether a separate device, or within a smart trainer) very effective for this, there has been at least one occasion in recent memory where I’d over trained, under replaced, and I simply couldn’t get the watts up (- yes make your own jokes with it)
Now its probable that there was a lot of general fatigue as well, but at the end of a hot, sweaty day already, its possible that I wasn’t in the best biochemical state before I got on the bike either
Other symptoms that can be seen in hyponatraemia are listed below. The further down the list, the greater the sodium deficiency
- Lethargy – from a medical perspective, if I see a sportsperson in the clinic who is “tired all the time” one of the first things I’ll be looking for in the blood is their sodium levels.
- Seizure – this is the sort of thing which kills marathon runners/iron man contenders
Skip and you’ll pay
It is possible to think that you are looking after yourself, yet may actually be putting yourself at risk, with the “we all need to drink more water adage”. What I mean by that is putting too little electrolyte solution in your ride bottle, and taking on extra water, compared to the salts during the day before a race you might throw out your carefully balanced system. The above graphic from Netter’s Physiology shows what is supposed to happen if you have a low blood pressure due to not drinking enough (volume contraction)
Normally if you are not replacing enough salts, yet you are still taking in the fluid, your body will detect this and act accordingly by making you pee more. In this situation, your kidneys will keep the electrolytes your body needs and pass the rest of the fluid into the urine. Your body controls this though checking the osmolality of your blood – essentially how salty it is. But if you are doing major hours on the turbo, and lots of sweat, drinking too much water, or not enough salts whilst exercising, your body can go a bit…odd and you get something call SIADH. Syndrome of Inappropriate
excess unbalanced water you are taking on gets absorbed, and not filtered out into the urine. Your body was too busy chasing that KOM to focus on which hormones it should be producing. This then further lowers the sodium in your blood, in addition to that you are already pushing out in
Previously marathon runners have died as a result drinking too much – even in 2012, in spite of guidelines being changed to advise approximately 500ml of fluid to be consumed over each hour of a race, (previously, when trying to take on a litre of water an hour.
Sports electrolyte drink – Slow and steady wins
The main point about this is to drink about 500ml of isotonic solution for hydration for every hour of indoor cycling or any endurance activity. This should be relatively easily absorbed. But
Well, I hope that has given you a little more of an idea about why we need to drink when it comes to sports electrolyte drinks, and what we need to drink when exercising. Feel free to shout out in the comments below which drinks you find taste the best!
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