By Rachelle Healy
Many of our clients at MoreFit at some stage or another decide to enter an endurance event (2 hours or over) – here are the basics of endurance hydration.
On race day even the fittest people can suffer the consequences of a poor hydration and nutrition strategy. This article is focusing on hydration. Even though this is geared at Endurance, those of you taking part in the Hyde Park Run will benefit from hydration guidelines in this article.
As much as you prepare physically for events, hydration and nutrition are often the difference between crossing the finishing line well, crossing it in bits or not crossing it at all.
Recently I had the pleasure of being the nutritionist for the UK only 4 man team to participate in the Race Across America. RAAM is a 3000 mile race from the West – East side of the USA, crossing 12 states and climbing 170 000 vertical feet.
To give you an idea of RAAM:
- The RAAM route is around 30% longer than the Tour de France. Racers must complete the distance in roughly half the time allowed for the Tour. The Spinhalers completed in under 7.5 days with all riders finishing in great condition – considering!
- Our team of 4 riders weighed between 67kg and107kg which meant each members requirements in terms of hydration, electrolytes and calorie consumption were very different and had to be individualised.
- The team were racing in extreme conditions such as the desserts in Kansas and climbing the Rocky Mountains in extreme heat with a lack of shade or breeze. The protocols in place and monitoring our riders throughout was essential to the success of the trip and rider welfare.
- It was vital we had a system in place, vital we monitored outcomes and adjusted accordingly and vital we were consistent in the execution of this. Basically what I’m trying to say is you just can’t ‘wing it’ on the day!
The average person sweats between 0.8 to 1.4 litres per hour during exercise, however you need to factor in other elements such as heat, humidity,wind factor, sunburn etc as these all affect hydration levels on the day. A .5% reduction in hydration will start to affect your performance.
When hydrating, water isn’t the only thing to think about, it is essential that you supplement with electrolytes as well.
Electrolytes are important because they are what your cells (especially nerve, heart, muscle) use to maintain voltages across their cell membranes and to carry electrical impulses (nerve impulses, muscle contractions) across themselves and to other cells. Your kidneys work to keep the electrolyte concentrations in your blood constant despite changes in your body. For example, when you exercise heavily, you lose electrolytes in your sweat, particularly sodium and potassium. These electrolytes must be replaced to keep the electrolyte concentrations of your body fluids constant.
The sodium and electrolyte concentration of one litre of sweat can range from 300 mg to 3600 mg depending on the individual, and varies by diet, sweating rate, hydration, and degree of heat acclimation Under-replacing your sodium and other electrolyte losses can lead to various problems including dehydration, muscular cramping, headaches, gastrointestinal upset, nausea, fluid retention and hyponatremia.
Throughout the Race Across America, the riders would sip an electrolyte solution on the bike so they were constantly topping up their electrolyte levels.
If the riders were doing a tough shift in the heat or with hills or both, we would also add a more concentrated electrolyte tablet to their intake to counteract the excess sweating and loss of electrolytes and monitor outcomes.
It is very important to sip little and often and not drink huge amounts in one go as your intestines can only process so much at any one time, otherwise the rest will just go through you.
We used the following as a guide for hydration and monitored outcomes:
- Average Athlete / Average Temperature: 2-0-25 oz/hr – approx 590-740 mls/hr
- Lighter Athletes / Cooler Temperature: 16-18oz/hr – approx 473-532 mls/hr
- Heavier Athletes / Hotter Temperature:Intakes upwards of 28oz/hr – approx. 830 mls/hr A regular-to-large size water bottle is equivalent to 20-25 oz (approx 590-740 mls) and that’s an excellent gauge to work within.
Throughout RAAM, every 30 mins we took the riderstats – how many calories in, what type of calories– fat, protein, carbohydrate, how much fluid they drank and we recorded how often they peed and yes, what colour it was, as that is a very good indication of if your body is dehydrated or not.
If their pee was dark, we would hydrate more in 250 mls increments per hour with an electrolyte tablet/drink and monitor outcomes.
Other dehydration symptoms are to look out for are:
- Extreme thirst.
- Extreme irritability and confusion in adults.
- Very dry mouth, skin and mucous membranes.
- Little or no urination — any urine that is produced will be darker than normal.
- Sunken eyes.
The opposite to dehydration is Hyponatremia. Drinking too much water during endurance sports is more common than you think and the result can be devastating. Too much water causes the sodium/electrolytes in your body to become diluted. When this happens, your body’s water levels rise, and your cells begin to swell. This swelling can cause many health problems, from mild to life-threatening.
To avoid hyponatremia, fluid intake should not routinely exceed 28 oz/hr (830 ml/hr). The exceptions are heavier athletes, athletes exercising at extreme levels (prolonged periods at a high percentage of VO2Max), and athletes competing in severe environmental conditions.
During RAAM If the rider was peeing a lot, this was an indication that they didn’t have enough electrolytes in their system. Our first action was to increase their electrolyte intake and decrease their fluid intake to the minimum amount for the activity and conditions. Again, we would monitor outcomes.
A sign the body is low in electrolytes is excesspee’ing and sloshing (nausea) feeling in the stomach.
Other symptoms of hyponatremia are:
- Loss of energy and fatigue.
- Restlessness and irritability.
- Muscle weakness, spasms or cramps.
You can also take on too many electrolytes causing Hypernatrimia.
Hypernatremia typically does not have many symptoms until your blood sodium levels are extremely high. Symptoms include dizziness when changing positions, vomiting and diarrhoea. You can help lower your sodium levels by drinking plenty of water.
During the race we used both isotonic drink solutions and Hypertonic solutions depending on what was required.
Isotonic drinks contain similar concentrations of salt and sugar as in the human body.
- They quickly replace fluids lost through sweat and supply a boost of carbohydrate.
- They are the preferred choice for most athletes, including middle and long-distance running or those involved in team sports. Hypertonic drinks contain a higher concentration of salt and sugar than the human body.
- They quickly replace fluids lost by sweating.
- Suitable for athletes who require fluid without a carbohydrate boost.
Prior to leaving for the States, the riders did a sweat test. This involved taking their weight before and after cycling at race pace in a sauna for 30 mins in their cycling kit, helmet, gloves the lot!
Unfortunately we didn’t have the means to do the electrolyte sweat test, however what we did get was an indication on how much fluid each rider would be losing and this helped us prepare for the race ensuring we had enough water in the support cars and an indication as too how many electrolyte supplements we would need to purchase for the 24/7 race.
Following this, we put in place rehydration protocols to ensure our riders had optimal hydration. We weighed our riders in only their underwear before and after each shift and then rehydrated as necessary.
- For every pound of body weight lost we would replenish with 600 mls of water + electrolyte solution.
- We also ensured we used plenty of Himalayan Rock Salt when cooking their foods as it contains many trace elements and is a super electrolyte source.
- In these extreme events, the priority was hydration over sleep as you can exercise tired, but you can’t if severely dehydrated.
With dehydration, hyponatremia and hypernatremia you will find that if you’re monitoring outcomes and rectify the problem in the early stages through increasing/decreasing fluid intake or increasing electrolytes, the body adapts and the symptoms can disappear fairly quickly.
When planning for endurance events be it 2 hour or 24 hour + the more prepared you are, the more you monitor the more chance you have of finishing well.
[author] [author_image timthumb=’on’]https://www.morefit.co.uk/wp-content/uploads/2014/10/Rachelle-Healy-MoreFit-Personal-Trainer1.jpg[/author_image] [author_info]Rachelle Healy is a Personal Trainer at MoreFit St Paul’s Motivation: “I want to make you the best version of yourself.” If you are planning an endurance event and would like some help with hydration and nutrition, please get in touch with Rachelle at Morefit St Paul’s. [/author_info] [/author]