[This is a long post so tuck in with a cup of tea 🙂 ]. Keeping yourself properly fuelled during a long bike ride is paramount to your success at sportives. Research suggests that a loss of 2-3% bodyweight due to dehydration alone can reduce cycling performance by as much as 10-20%!
Similarly, without keeping your carbohydrate stores topped up on a long bike ride, you will experience the dreaded ‘running out of energy’ symptoms which include dizziness, shakiness, a huge craving for sugar and a significant decline in your speed on the bike – all to be avoided!
You therefore need to combine both your hydration strategy with your energy strategy to keep you in peak form throughout your sportive. This post covers hydration. For carb energy fuelling please read Best Foods To Eat On Long Endurance Rides
In reality though, you will experience a little dehydration after a long event as it’s impossible to keep up with your fluid losses 100%.
Your overarching goal then is to keep this dehydration to a minimum i.e. cover your losses the best you can. As you'll soon see, hydrating optimally is all about a compromise, erring on less fluid than more in most cases...
What Fluid Is Best For Long Bike Rides?
Never drink plain water if you are riding more than an hour, as it can lead to a potentially fatal condition called hyponatremia. This is when too much salt + vital minerals called ‘electrolytes’ are leached from your blood and cause a serious blood imbalance.
So instead of water, you are looking for ‘fluid’ that replaces these lost electrolytes AND keeps up with your hydration needs.
In other words, your body needs a fluid that is in balance with your blood.
Three types of fluid concentrations you need to be aware of in sports drinks:
In conclusion then, you’re looking for an isotonic solution to keep you hydrated on all your bike rides.
To help maintain hydration on a long bike ride drink an "isotonic" electrolyte solution instead of water.
Best Hydration Strategy When Starting Out?
If you’re new to using an energy hydration drink, start out with Isostar. This is an isotonic solution, very reasonably priced and you can either buy it online, or buy it down your local supermarket.
I’ve used Isostar for years and it’s always worked incredibly well in hot weather and for my long distance bike rides. I also find it digests easily on my stomach than other sports drinks I’ve tested.
That having been said, it’s important to highlight that everyone has different tastes. Isostar may not suit you, but I think it’s one of the best products to start out with.
Salt for long rides - myth or truth?
Salt is washed out the system by sweat if not replaced. Salt is a very important mineral for the body, especially your heart muscle! Continually drinking fluids like water, or formulas weak in salt replacement, can in rare cases, lead to a condition called hyponatremia.
Salt helps to hold water in the stomach and therefore can aid hydration. Always check there is enough salt in your solution - but do not over do it!
Salt is toxic at high levels of ingestion.
If not you can add a very small pinch of salt yourself to a bottle before long ride. For a more qualified read, I highly recommend this informative article by Bicycling.com: How Much Sodium Should You Consume.
As summarised from the article above, "As a general guide, a good rule of thumb is to consume between 500 and 700 milligrams of salt per hour, which is about how much you can absorb within that time".
Always read the label of any sports product before using it. Be warned that Isostar has many types of hydration products with a slightly different suit of electrolytes. Some don't have magnesium or potassium or salt, others do!
You want the full suit of electrolytes because they ALL play a role in the body, specially when riding a bike: sodium, potassium, magnesium, calcium, chloride, B vitamins and salt.
To save you time, know that only the orange and lemon flavour powder tubs (at time of writing 2018), have a full list of electrolytes. The hydration tablets look to have a stronger suit, specially a little more salt. You can try both and see which one suits.
Arguably, the hydration tablets are best, in my opinion!
Read this great article on electrolytes to find out why they are so important. Otherwise, look for the above minerals and vitamins as a general rule of thumb.
When should you drink an isotonic solution on your bike?
Take some big mouthfuls of fluid from the first 15 minutes you are on your bike and then roughly every 10-15 minutes throughout your bike ride.
Start from the beginning of your ride or event even if you don’t feel thirsty.
Some new research suggests you should wait until thirsty before drinking - ok for a short one hour bike ride; not ok if you're seriously going any distance for multiple hours!
Signs of thirst usually indicate too late that we are ‘already’ dehydrated. The notion that dehydration has minimal effects on the body - well you just have to read my real-life case study (below) for proof of how dangerous it really is to delay drinking for endurance sports.
As a test, simply check your urine colour about home when you 'wait to feel thirsty' - you'll see what I mean! The colour is likely going to be distinct orange - a sign of dehydration. When hydrated the colour is usually pale. You really want to ward off this dehydration state for as long as possible, when on a long bike ride!
What isn't clear in this new research is electrolyte replacement. In my opinion, you should begin replacing from the get go on a long bike ride! This doesn't mean over-drink, but learn to take some mouthfuls often IS important.
Use common sense. I'm not a lab geek. I just go on my own real-life field experience with a pinch of common sense. My following tests are what work for me out on the road, and may reflect differently from what happens to you or in a laboratory.
How much to take with you during a sportive long distance ride
Take two big cycling bottles (750ml each) with you on ALL your long bike rides. You should get used to carrying this amount of fluid on every bike ride you do and practice drinking from your bottles regularly.
You can set a watch to remind you, but after a while you’ll get into a habit of swigging from your bottle at safe, convenient moments along your route.
If you have an event coming up, do what you do in training. If that’s using Isostar, then continue using it! Don’t change your product the week before your event or you line up for things going ‘pear-shaped’ hydration wise.
I know it’s tempting to use what’s been given to you in your goody bag by the organiser. Sometimes you might find the odd appealing sachet to try. Only ever experiment with new powders or tablets in training – never the next day in an event!
Plan your hydration in advance by estimating how much you need. As a rule of thumb, I go through one big bottle (650-750ml) an hour on most bike rides, but if it’s warmer weather, this usually increases a little...but you don't need to guess this - you can calculate it...
Calculate Your Sweat Rate To Figure Out Your Hydration Needs
A great way to get a ball park "estimate" of your sweat rate per hour is to weigh yourself before and after your rides to make sure that you are drinking adequately to replenish your fluid losses...
Use this sweat rate calculator to quickly calculate how much fluid you lose in 1 hour, as well as remember to add in how much you drank during that test ride. From these results you can find out how much fluid you need to drink on the bike per hour to help replenish your fluid losses.
-- LIVE CASE STUDY AND MY FINDINGS TO PASS ONTO YOU --.
My live sweat-rate case study in a recent Bike to Run, totalling a 2hr 17 minute effort at a hard tempo-race pace, going by 'new research' that states "be guided by your thirst"...
My test mimicked an Olympic Distance triathlon event in a time I usually complete the event 2hr17 (bike to run only). You could simply do a 2 hr ride to test too, so don't worry about the sport in this live case study, - just measure intensity (needs to be at the pace you'll ride at) and duration:
I'd go for 2 hours to get a good sample result, **remembering that I'm going by the new advice "be guided by your thirst":
Simple Sweat Rate Calculation:
What was the change in bodyweight?
Weight Before Workout: 54.5kg.
Weight After Workout: 52.9kg
Change in bodyweight (before kg - after kg) = 1.6kg
How much fluid intake during ride total?
750ml (1 big bottle of electrolyte) + 350ml (of a small bottle) during 137 minutes. (This is roughly a consumption of 482ml / hr - just under one small bottle/hr).
How many minutes did you exercise?
2hrs 17 minutes or 137 minutes of race pace effort.
SWEAT RATE/L/hr = 1.1L per hour @ 24C; 80% humidity
I lose 1.1L per hour on average guesstimate at a hard effort. That's a lot of fluid for a 54kg female!
More importantly, by following "be guided by my thirst" - this translates to approximately a 3% decrease in bodyweight for 54kg mass by the end of 2hrs17.
According to the body % weight loss chart below, that's a seriously declining performance when I hit the last 10km run / 50 minute effort! I lose many minutes, not seconds...and explains much of my poor run performance in triathlons!
Yes, it 'feels' terrible too. In Zurich Olympic Distance 2016, before I did a sweat test analysis, I felt goose bumps all over my body - slight dizziness - mood turning negative - want to stop - not enjoying it - searching for the finish - having everyone pass you on the run - slurred speech at the end and craving fluid with a light headache! Not great.
Oh dear Rebecca...yet I followed the new hydration guidelines :(.
Remember the effort was only 2hrs 17 minutes! It shows that knowing your sweat rate for short rides (or triathlons) IS important. In fact, it's rather critical! The upshot is, don't assume hydration strategies are only meant for ultra endurance athletes...
Dehydration is very real (for me) here for similar length bike rides too, even if the run is slightly more demanding in a triathlon and will therefore demand more fluid. You can clearly see it would be dangerous for me to take part in longer triathlons **if guided by thirst alone**...
SYMPTOMS BY PERCENT BODY WEIGHT WATER LOSS:
PERCENT WATER LOST --------- SYMPTOMS:
0% --- none, optimal performance, normal heat regulation
1% --- thirst stimulated, heat regulation during exercise altered, performance declines
2% --- further decrease in heat regulation, hinders performance, increased thirst
3% --- more of the same (worsening performance) me!
4% --- exercise performance cut by 20 - 30%
5% --- headache, irritability, "spaced-out" feeling, fatigue
6% --- weakness, severe loss of thermoregulation
7% --- collapse likely unless exercise stops
10% -- comatose
11% -- death likely
[Nutrition for Cyclists, Grandjean & Ruud, Clinics in Sports Med. Vol 13(1);235-246. Jan 1994]
So you get the point. Now let's look at how I found a far safer hydration strategy than "be guided by your thirst". First, a little more research on hydration...
Replenish Fluid Loss, do not try to Replace it ALL!
According to a recent article by Hammer Nutrition, it sensibly says,
"endurance outcome is to postpone fatigue, not replace all the fuel, fluids, and electrolytes lost during a sportive."
Indeed, as I mention at the beginning of this post, it is physically impossible to replace all the fuel lost.
Moreover the post continues,
"..at the most, you can absorb about 1 Liter (approx 34 fluid ounces) of water per hour, but only in the most extreme heat and humidity. Most of the time you can only absorb about half or not too much over half that amount, even though it won't fully replace your losses....Repeated intake of 1 Liter (about 34 fluid ounces) per hour will ultimately do you more harm than good."
Most of the time your body can't absorb greater than 500ml-750ml each hour on a ride - that's up to 1 big, bottle of fluid per hour.
Finding a Better, Safer Hydration Strategy "Be Guided by SWEAT RATE"...
So if we have to replenish, not replace all our fuel needs, I can now re-calculate how much I'd safely need to consume on a 2hr17 bike ride:
If I consume approximately 1 big bottle an hour (750mls/hr) that's pushing the absorption limit, but with a 24C ambient air temperature this is doable. I definitely could not drink 1 Litre an hour - that would be uncomfortable and put me at risk of adverse electrolyte imbalance.
On re-calculation then,
1 x 750ml an hour leaves me with almost 1% bodyweight change.
I came to this answer via the following calculation, working with numbers from my sweat test above:
1. Net fluid loss = 1100 (sweat rate/ hr) - 750ml (compromised fluid intake / hr) = 350ml net loss of fluid
2. 54.5kg - 0.350ml (net fluid loss) = 54.1kg
3. (54.1 / 54.5) x 100 = 99.3
4. 100 - 99.3 = 0.7% bodyweight lost approximately/hr at this rate of replenishment
The chart shows that I am in the manageable area of dehydration, at ball park 1% bodyweight lost. This is my best compromise between drinking too much and drinking too little on warm summer days.
According to the above Symptom Chart: 0.7-1% loss in bodyweight, I have negligible side effects to performance. The results speak for themselves.
The final results show quick comparisons in approach to hydration:
You can see that erring on LESS fluid rather than MORE is key here for optimal hydration - as is learning to drink early on your bike rides.
So instead of "being guided by your thirst to drink", be guided by your "sweat rate" for long rides and start earlier rather than later to begin hydrating!
Be realistic, if you're a big sweater like myself and the event is roughly 4 hours, and it's going to be 30C - the advice above is critical for you because you don't want to induce a dangerous heat stroke injury.
Taking numerous sweat tests on various training rides in different conditions to compare and contrast data, will likely be extremely useful to you.
As mentioned, fluid replacement is just one part of your cycling fuel strategy. You importantly also have to find a way to keep your carb stores topped up on a long ride. A post you might find useful on this is What to Eat and Drink on Long Rides.
Additionally, you need to understand how to recover by refuelling, or 'rehydrating' adequately before your next ride...Pointless starting out on a a ride dehydrated!
We've covered quite a lot in this rather long post, although I felt I had to cover everything because hydration on bike rides is a critical factor in your cycling fun, success and good health...
Yes, I've given you a case study that contradicts new research and will be shot down by many. However, do note that the human body has not changed much when it comes to hydration - and there have been countless research done with similar conclusions to mine above when it comes to the subject of exercise and hydration strategies.
- I believe the latest guidence on hydration wants you to refrain from drinking too much which I agree with, but what I absolutely disagree with is the advice "be guided by your thirst" . This is a dangerous blanket statement especially when it comes to cycling hours in the saddle or triathlons.
...but hey, as I always say and will say again: FIND WHAT WORKS FOR YOU and stick with it...no matter what the lab geeks come out with - always test it yourself on rides, to come to your own conclusions.
Don't suffer needlessly - try the sweat test and let me know below how you've found it to improve your rides.
Quick Summary Points: