CYCLING PERFORMANCE TIPS -

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CYCLING PERFORMANCE TIPS

  Last updated: 11/15/2018

Hydration


Although water doesn't contain Calories, adequate fluid intake and hydration are at least as important as Calorie replacement in maximizing athletic performance. Failing to replace fluid losses is the biggest error of many competitive athletes both while training and in competitive events. Failure to maintain hydration is especially common in cycling where significant evaporative losses can often go unnoticed even as fluid loss from sweating and expired air (up to 60% of total losses) can easily exceed 2 quarts per hour.

To maximize performance it is essential that fluid replacement begin early and continue throughout a ride. Fluid losses during exercise decrease circulating blood volume as well as the water content of individual muscle cells.

An it can happen quite quickly. A South African study comparing two groups of cyclists (one focusing on staying hydrated, the other not) exercising at 90% of their personal VO2max, revealed a measurable difference in performance as early as 15 minutes into the ride. A great warning as to the importance of anticipating and regularly replacing fluid losses.

The impact on performance is directly related to the level of dehydration.

Thirst is not a reliable indicator of the level of dehydration and often is not triggered until one has lost 0.8 - 2% (of body weight).

Maintaining an adequate plasma volume is a key component of the overall strategy to optimize physical performance.

Hydration and Performance - is total volume replacement necessary?

This article highlights how conclusions on optimal hydration have changed over the last 50 years. Work from the 1960s through the late 1980s touted complete fluid replacement as the goal for maximize endurance performance. This philosophy was codified in 1996 in the American College of Sports Medicine (ACSM) fluid replacement Position Stand which urged the full replacement of sweat loss during exercise.

But then things started to shift. Based on additional studies and observations of real life performance, the ACSM revised its recommendations on fluid replacement in 2007 proposing a goal of 400-800 mL/h, varying depending on the athlete's size, environmental conditions, and exercise intensity. It shifted the goal from maintaining complete rehydration to limiting fluid loss to less than 2% of body weight.

About the same time the theory of a central governor was being proposed. This theory proposed the idea of an area in the brain (the central governor) that integrated multiple sensory inputs and then modified exercise (limiting it in certain cases such as overheating) by limiting the neural signals to muscle cells. In that way it protected the athlete from the harm of excesses in endurance and sprint activities. This theory suggested that it was the sensation of thirst, rather than the absolute level of dehydration that was the critical factor leading to a decrement in performance.

We continued to see a further shift toward acceptance of "thirst" as the most reliable indicator of fluid needs (much akin to using perceived exertion as a measure of exercise limits in training) until we had this study that questioned even thirst as an indicator of dehydration (of a degree that limited performance). The article as well as comments excerpted from an additional article by the lead author are the basis for this conclusion.

Then we have this paper which also demonstrated that thirst does not impact performance (presumably via an input to the central governor) impact performance....but dehydration does.

So it seems we have come full circle in the focus on thirst, which seems to have been discredited as a performance factor. But what about an actual total body fluid deficit (dehydration)? We have just a single study which is out of step in indicating that modest fluid deficits do not impact performance. But 4 other examples that do:

What have I concluded from these studies? What do I plan to do? Although I continue to see an occasional article suggesting some latitude as far as fluid replacement, giving those of us who are not good at fluid replacement an easy out, common sense tells me that the more you are in physiologic balance (homeostasis), replacing fluid (as well as glycogen) losses during and after a ride, the more competitive I will be in endurance events.

Hydrating

How much water do you need to maintain a normal state of hydration without a daily exercise)? For a 70 kilogram adult, about 2500 to 3000 cc per day. This equates to about 4% of your body weight If your diet is well balanced, approximately 1000 cc (4 cups) is water in fruits, vegetables, and other foods you eat. Another 1 cup is produced when your body metabolizes carbohydrates, and the balance - about 7 cups - needs to be fluids you drink.

If you then exercise for an hour or two, add in replacement for the losses from sweat and respiration. Under normal environmental circumstances, you will lose 1 - 2 liters of sweat per hour, and if the ambient temperature is high, this can be as high as 4 - 6 liters per hour.

What are other factors, besides exercise, that can influence your fluid needs (and exacerbate dehydration)?

Under normal conditions, while riding you should be taking in a minimum of 4 to 5 ounces of fluid every 15 minutes or 1 to 2 standard water bottles per hour. When extreme conditions of heat and humidity are anticipated, and the risks of dehydration are higher, the following strategy of maximizing hydration before you start the activity can be a good preventative measure.

If you want a simple measure of the effectiveness of your personal hydration program, weigh yourself before and after a long rides (without clothes to avoid inaccurate weights from sweat soaked clothing). A pound of weight lost equals 16 ounces (1 pint or 2 cups) of fluid; a quart (4 cups) is 2 pounds. For the purposes of calculating your replacement needs, a standard water bottle (20 ounces) weighs about 1 1/4 pounds. With this information, you can tailor YOUR OWN fluid replacement program.

For those who practice the philosophy of "if a little is good, a lot is better", it should be mentioned that there are risks associated with over correcting fluid losses of exercise. There have been reports of hyponatremia (low blood sodium concentration) resulting in seizures in marathon runners who over replaced sweat losses (which contain both salt and water) with water alone. This is rarely a problem for cycling events less than several hours in duration (except under extreme environmental conditions of heat or humidity) and becomes a potential problem only for events lasting more than 5 hours.

HYDRATION TIPS

Q. Do electrolyte drinks (those containing minerals such as sodium and potassium) provide an advantage over pure water alone?

A. Not for rides of 1 to 2 hours. When two groups exercised for 2 hours at 67% VO2 max (with average fluid losses of 2300 ml) there was no advantage to rehydrating with electrolyte drinks versus water alone. For longer rides, especially over 5 hours in duration (100 miles) or in conditions of extreme heat and humidity, using electrolyte containing drinks for sodium replacement will decrease the risk of dilutional hyponatremia. With the large volumes needed for rehydration in long events, palatability and digestive tract tolerance are important in the selection of a replacement fluid.

In extreme conditions you might consider adding a pinch of salt to each water bottle of electrolyte replacement drink. For example, Gatorade doesn't contain much sodium. This added salt will help to prevent hyponatremia. In the same way, salting your food liberally the day before a hot-weather ride may help and there are personal stories that this prevents cramps in some individuals. A word of caution, if you are on a sodium restricted diet, check with your physician to make sure that adding salt won't be a health hazard for you.

Additional thoughts on drinks for those longer rides (and keeping hydrated):

ARE YOU HEALTHIER ON 8 GLASSES OF WATER A DAY?

Is there a minimum fluid intake per 24 hours that is needed to "flush out toxins" and help us maintain health? The short answer in this nice summary is "no". There is:
  1. No evidence that increasing fluid intake decreases kidney disease.
  2. No evidence that increasing fluid intake decreases the risk of heart disease or stroke (but note: once again there is a correlation between increased coffee intake and decreased cardiovascular risk)
  3. No evidence that increasing fluid intake improves skin tone and luster.

IN SUMMARY

In summary, drinking 1 to 2 quarts per hour of plain water is adequate for rides of 1 1/2 to 2 hours. For longer rides, where the body's glycogen stores will be depleted, carbohydrate containing fluids take on increased importance (glucose containing liquids can deliver Calories from the mouth to the muscles in as little as 10 minutes as compared to solid foods and energy bars which empty more slowly from the stomach). In most individuals, an 8 to 10 % concentration is the optimal. Glucose polymers provide the ability to increase total Calories per quart without risking the side effect of an unpalatable, sweet taste. Aside from palatability, there is no proven advantage of polymer containing drinks over simple sugar (glucose) drinks. Although there are many commercial drinks available, the old standbys of apple juice and cola drinks are probably the least expensive per Calorie provided. In the pre and post ride period, the high Calorie, easily absorbed, glucose polymer sports drinks offer an advantage for taking in large amounts of carbohydrate in the sweet spot of 30 - 60 minutes post ride aiding rapid rebuilding (or restocking) glycogen stores. For those of you interested in saving a few $$, take a look at this site for some ideas on homemade energy drinks.

For longer rides, don't forget the risks of overdoing rehydration with pure carbohydrate (electrolyte free) drinks alone. If you plan to ride more than two or three hours, it's worth considering a commercial electrolyte containing drink, and if you are going to be riding 5 hours or more, it is essential to pace your fluid replacement rate (and keep an eye on your weight during training rides to be certain you are not overcompensating).

And drink when you are thirsty - not to meet a predetermined minimal daily fluid intake.


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Cycling Performance Tips
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