Fanylion Mountain Bike Team
Official site of the Fanylion Mountain Bike Team. Includes mountain bike ride guides, gear reviews, bike maintenance, team reports and rider profiles of the Fanylion Racing Team.
In this section
Hydration
Mountain biking is a pastime that crosses the spectrum from super fit cross-country racers to sporadic recreational riders. Although physical performance may differ greatly between each group within the mountain biking fraternity the basic physiological demands are similar. No matter what type of riding you partake in, your body needs to have its fluid and nutritional levels replenished. This is not only to maintain performance but also for comfort and most importantly safety.
Fluid intake becomes more important as the intensity and length of rides increase. Pre-hydration and re-hydration are vital to maintaining cardiovascular health, correct body temperature and muscle function. Research has shown that dehydration is a major cause of fatigue, decrease in performance, decrease in coordination and cause of muscle cramping. Although it is common knowledge among many mountain bikers that they need to hydrate during rides it is not simply a matter of consuming large quantities of water.
Pre-Ride Hydration
To do the job properly it is important to start your hydration prior to your ride. In the days before, make sure that your nutrition is balanced and that you do not become dehydrated or take on board large quantities of alcohol (alcohol causes water loss from the kidneys due to inhibition of the hormone ADH) leading to marked dehydration. The crude test for dehydration is checking the urine; the darker the colour the more dehydrated. On the day of your ride it is advisable to have an intake of 500ml of fluid 2 hours before you start. This provides time for good hydration and excretion of any excess fluid before you start riding. It is also not a good idea to have a high fat meal prior to the ride as fat is known to inhibit gastric (stomach) emptying and reduce plasma glucose levels. Without going into detailed information about nutritional preparation it may seem obvious that a good balanced diet in the days prior to the ride is essential. Concentrate on consuming complex carbohydrate foods, with some protein during the final day and morning prior to the ride. Complex carbohydrates include:
Pasta
Brown Rice
Potatoes
Other root vegetables (that Team Ewok has finished with)
Wholemeal/granary/brown bread
Pitta bread
Bagels
Breakfast cereals
Porridge oats
Crispbreads/Ryvita/Oatcakes
Corn
Yam
Peas
Beans
Lentils
And so on.
Intake during ride
You should start taking on fluids early during the ride and not wait until you are thirsty. A ‘little and often’ policy is most effective, preventing taking on too much fluid and passing it straight through the system as excess. This prevents wastage and running out of fluids early during the ride. It also prevents nausea from over-filling of the stomach. Try and make the fluids cooler than ambient air temperature, approximately 15-22 degrees Celcius is ideal. This allows for cooling benefits without the fluid being too cold. If the ride extends over an hour research suggests that the fluid should contain additional carbohydrate and electrolytes. Below the one hour mark there is no evidence of an effect on performance by ingesting extra carbohydrate. This does not mean that they cannot be used before this point however.
It is suggested that carbohydrate should be introduced at 30-60g/h. This rate of carbohydrate intake can be achieved by drinking 600-1200ml/h of solution containing between 4%-8% carbohydrate (g/100ml). This concentration supplies sufficient carbohydrate without affecting isotonic balance. In other words if the solution is too concentrated it has been shown to effect re-hydration due to slowed gastric emptying and slow water uptake. You may want to buy a premixed drink, a power or liquid concentrate or make up your own drink with cordial/sugar/salt etc.
Research suggests that as little as a 2% drop in body weight due fluid loss, can lead to a drop in blood volume (hypovolemia). With a drop in blood volume there is an increase strain on the heart to push the smaller volume of blood around the cardiovascular system. There is also evidence that there is an increase in vascular resistance in the peripheral blood vessels to the arms and legs with hypovolemia. This is due to vessel constriction that maintains the central arterial blood pressure and so delivery of oxygen to the essential organs. If there is decreased blood flow to the arms and legs there is less oxygen and so performance decreases.
Sports Drinks
Sports drinks/ Energy drinks, what are the differences? Energy drinks are beverages which contain legal stimulants, vitamins and minerals, including caffeine, guarana, taurine, various forms of ginseng, maltodextrin, carnitine, creatine, and ginkgo bilobaare (no, I didn’t make that one up). Sports drinks on the other hand are usually isotonic drinks with sugar, electrolytes and other nutrients. Sports drinks are seen to be useful to those riding at a relatively high intensity for 90 minutes or more. The fluids should supply in the region of 60 to 100 calories per 8oz of fluid to help maintain performance.
There is also a certain amount of research supporting the implementation of a post ride drink which contains both carbohydrate and protein. It has been shown that carbohydrate and protein drinks taken immediately following endurance activity leads to increased insulin levels which controls the amount of glucose converted to glycogen (polysaccharide storage molecule in the liver and muscle tissue). In doing this the time period required to gain full glycogen storage levels is believed to be quicker (normally takes 20-24hours with normal nutrition) this means there should be more energy available for subsequent rides.
The research suggests that there may be a threshold level of protein to stimulate the increase of insulin. It is outlined as possibly 8g. It is also believed that having protein present during and immediately after exercise provides amino acids for muscle repair, development, and it may also decrease the amount of post exercise muscle soreness. There are premixed drinks available from manufacturers such as High 5 which provide a carbohydrate and or carbohydrate protein mixture. Or you may just decide to mix whey protein drinks with carbohydrate drinks instead. The advantage of consuming carbohydrate and protein means that it can be put into the system much quicker than solid food. The faster these nutrients are put into the system the quicker they can be utilised for glycogen replenishment and muscle repair.
The consumption of alcohol post exercise is physiologically not the best idea for a number of reasons. There will be further dehydration through the process mentioned above. Another reason is that alcohol causes dilation of blood vessels with can lead to more bleeding at any internal injury. (More swelling, pain and slower recovery). This is also the case in certain muscle tissue where there will be micro trauma following endurance activity.
My post ride drink is several pints of Stella with a large fillet steak (medium rare) with chips, mushrooms, peas and onion rings, Thank You very much (and a nice midget for dessert).
Electrolyte considerations
Although the body has a store of electrolytes such as sodium and potassium, it is unlikely that these will be depleted during normal training sessions or short rides over a few hours. Problems arise when you start considering rides in excess of 4 to 5 hours. At this point it is possible that stores within the body are low and the rider should consider using a complex sports drink with electrolytes to prevent the depletion. Riders who do not replace electrolytes via their intake run the risk of over hydration and hyponatremia. This is a physiological condition where there is a low blood sodium concentration. This lowered sodium concentration can have dire consequences.
Adequate sodium balance is necessary for transmitting nerve impulses and normal muscle function. Even a slight depletion of this concentration can cause physiological problems. In the worse case this decreasing sodium level can lead to coma and death.
Studies have shown athletes can lose more than 2 grams of salt per litre of sweat. If you then consider more than a litre of sweat can be lost in an hour. This means that over a 5 hour ride in excess of 10 grams of sodium can be lost. Replacing this loss of sodium during the ride is critical to performance and safety. It is possible to use products such as Dioralyte which is a medical electrolyte drink for severe diarrhoea. Don’t start taking Immodium as that won’t work! Unless you have the runs! In considering stomach upsets its important if you must ride in this situation, which is not advised. You must take into account the extra fluid loss.
What is hyponatremia?
Hyponatremia is a disorder in fluid-electrolyte balance that results in an abnormally low plasma sodium concentration (<135 mmol/litre; normal = 136-142 mmol/litre). A sustained decrease in plasma sodium concentration disrupts the osmotic balance across the blood-brain barrier, resulting in a rapid influx of water into the brain. This causes brain swelling and a cascade of increasingly severe neurological responses (confusion, seizure, and coma) that can culminate in death from rupture of the brainstem.
The faster and lower the blood sodium falls, the greater the risk of life-threatening consequences. A decrease in plasma sodium concentration to 125-135 mmol/liter usually results in either no noticeable symptoms or in relatively modest gastrointestinal disturbances such as bloating or mild nausea. Below 125 mmol/litre, the symptoms become more severe and include throbbing headache, vomiting, wheezy breathing, swollen hands and feet, restlessness, unusual fatigue, confusion, and disorientation). When plasma sodium concentration drops below 120 mmol/litre, seizure, respiratory arrest, coma, permanent brain damage, and death become more likely.
However, some athletes have survived hyponatremia of <115 mmol/litre), whereas others have died at >120 mmol/litre the hyponatremia that occurs in athletes is most often characterized by hypo-osmolality (hypotonicity) of plasma. This condition is known as hypotonic or dilutional hyponatremia, i.e., more water than normal for the amount of substances dissolved in the plasma. (Taken from Gatorade Sports Science Institute).
Hyponatremia
The early warning signs are often subtle and may be similar to dehydration; nausea, muscle cramps, disorientation, slurred speech, confusion and inappropriate behaviour. (Inappropriate behaviour = out of character behaviour i.e. Team Hodgson NOT abusing small furry mammals). At this point many mountain bikers will increase the amount of water they are drinking believing the symptoms are due only to dehydration. This increase in water only confounds the hyponatremia further.
If there is correct preparation followed by good hydration, nutrition and intake of electrolytes the risk of hyponatremia is greatly reduced. However at the first sign of muscle cramps, nausea or disorientation the rider should consume electrolyte rich fluids or eat foods that will provide sodium. Prevention is better than cure! There are dangers if the plasma sodium level falls too far, it must be raised in a controlled manner. If it is suspected that a rider may have hyponatremia and has progressive symptoms hospital is the best plan. In hospital plasma sodium levels can be measure and if significantly low the rate of replacement can be calculated. If severe this replacement will take place over a number of hours. This is more in the very low critical sodium levels but it is best to be aware and stop them from dropping low at all.
Below are a few bullet points worth remembering:-
Use a sodium containing sports drinks during long distance, high intensity events.
Eat salty foods before and during competition if possible.
As there are no steadfast guidelines for everyone, it is important for an athlete to understand his or her individual fluid needs.
Weigh yourself before and after training and drink enough sodium based sports drink to offset any fluid loss during exercise.
Increase salt intake by 10-25 grams per day several days prior to rides.
The increased sodium concentration will allow additional hydration with water to remain balanced so that the dilution of blood sodium does not occur.
Avoid use of aspirin, ibuprofen, and other non-steroidal anti-inflammatory agents as they may increase the risk of hyponatremia in endurance biking.
The above information is intended as a guide only. Each individual should take responsibility for their own hydration and nutrition during rides. Although correct hydration and nutrition will assist with performance it does not take the place of appropriate training and experience.
Happy Riding!
Team Boy Band
Fany fact
Hucking off a 10ft ledge is just like hucking off a 2ft ledge. It's the same technique, you're just in the air for longer.