CYCLING PERFORMANCE TIPS
Last updated: 11/04/2015
Although water is not a source of Calories to power your physical activities, adequate
fluid intake and hydration are at least as important as Calorie replacement
to maximize one's athletic performance. The single biggest error of many
competitive athletes is a failure to replace fluid losses during training and
competitive events. This is especially true in cycling where
evaporative losses are significant and can often go unnoticed even though
fluid loss with sweating and loss through the lungs can easily exceed 2 quarts
per hour. (Respiratory fluid losses are not insignificant. Up to 60% of overall
fluid loss can be via the lungs - which means that even swimmers can get
To maximize your performance, it is essential that fluid replacement
begin early and continue throughout a ride. A South African study comparing
two groups of cyclists (one focusing on staying hydrated, the other not) exercising
at 90% of their personal maximums demonstrated a measurable difference in
physical performance as early as 15 minutes into the ride.
Fluid losses during exercise decrease the
circulating blood volume as well as the
water content of individual muscle cells. The impact on performance is directly
related to the level of dehydration. Early dehydration is defined as a >1% loss
of body weight as a result of fluid loss. Unreplaced water losses equal
to 2% of body weight (about 3 pounds for the average rider) will impact heat
regulation, at 3% there is a measurable decrease in muscle cell contraction times,
and when fluid losses reach 4% of body weight, there is a 5 to 10% drop in overall
performance (which can persist for up to 4 hours after rehydration takes place).
Thus it is essential to anticipate and regularly replace fluid losses. Thirst
is not a reliable indicator of your state of dehydration as it is often not triggered until
one has lost 0.8 - 2% (of body weight). Maintaining an adequate
plasma volume is an important piece of an
overall strategy to optimize your physical performance.
Hydration and Performance - is total volume replacement necessary?
highlights how conclusions as to the benefits of optimal hydration on performance have
been changing over the last half century. Work from the 1960s through the late 1980s
supported complete fluid replacement as the goal to maximize endurance performance. This
was codified in 1996 in the American College of Sports Medicine (ACSM) fluid replacement
Position Stand that urged at least the full replacement of sweat loss during exercise.
But then things started to shift. Based on more in depth studies and observations of
real life performance, the ACSM revised its recommendations on fluid replacement in
2007 proposing 400-800 mL/h, varying depending on the athlete's size, environmental conditions,
and exercise intensity. It suggested that the goal be shifted from maintaining complete
rehydration to limiting fluid loss to less than 2% of body weight for optimal health
About this same time, the theory of a central governor and its
impact on performance was being refined. The theory is that sensory inputs to a
central area (in the brain) of neural exercise coordination can limit neural
outputs (stimuli) to the exercising muscles to limit muscle cell firing and as a
result protect the athlete from the harm of excesses in endurance and sprint
activity. 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.
I came to the conclusion (after a literature review in 2014) "...the recent
trend has been away from an excessive focus on fluid replacement - with an increased
acceptance of "thirst" as a reliable indicator of personal fluid needs (much
akin to using perceived exertion as a measure of exercise limits in training)."
But the pendulum continues to swing and we now have a study questioning even that
more liberal approach to fluid replacement - the focus on thirst as a better
measure of an indicator of dehydration (and limited performance) than using weight
loss or total % BW dehydration.
The details below are based on
this article as well as comments excerpted from an additional article by the lead author.
Although this result is intriguing, it is just a single study and as such will need confirmation
before we can take the conclusions to the bank. Here are 3 examples that indicate to me things are
still not crystal clear:
- Study subjects - 11 competitive cyclists and triathletes with experience with time trials
- Study protocol - a 90 min ride at a fixed rate (50% VO2max) followed by a 20 km TT. The only
feedback received during the TT was time every 1 km.
For all trials, participants had an IV in place. During both the 90 min steady ride and the
20 km TT, they either had 100% of their weight loss replaced with saline (warmed so they couldn't
feel its infusion) versus the IV as a sham with no fluid replacement. This avoided a conscious
awareness of fluid replacement.For some trials, participants were able to rinse their mouth with water, as much as desired,
while in other trials no rinsing was permitted.
- Results were grouped -
- hydrated and not thirsty (rinsing allowed)
- hydrated but thirsty (no rinse)
- dehydrated and thirsty
- dehydrated but not thirsty.
- Study conclusion: Neither physical dehydration of up to 3% body weight, nor the associated
sensation of thirst impaired performance of about 2 h in the heat.
So what do I conclude?
- Study 1 - A 2 to 2.5% decrease in body weight from pre-exertion dehydration significantly decreased time to exhaustion and power output on a subsequent hill climb challenge.
- Study 2 - An additional 1% decrease in body weight (overall 2.2 % total decrease compared to 1.2% decrease in the group allowed ad lib fluids) led to a 6 % (1 minute) increase in total time for a 5 K hill climb.
- And finally study 3 that demonstrated that
a 1% decrease in body weight affected speed and mean power output by approximately 1% in 3 cycles of a
simulated 5 K hill climb.
What am I going to do? Although this article suggests some latitude in fluid replacement, and gives an easy
out to those of us who are not good at fluid replacement, common sense says that the more you
stay in physiologic balance (homeostasis) and replace fluid (as well as glycogen) losses during and
after a ride, the more competitive you (and I) will be in endurance events.
- A relentless focus on total replacement of actual losses is not required
in endurance activities.
- Drinking when thirsty will increase the rider's overall sense of well being and help the cyclist maintain a positive attitude (self confidence) as to their ability to maintain that level of exertion.
- There is little support for the idea that thirst alone has a subconscious impact (central governor theory) to limit performance.
- There is conflicting evidence on the impact of water losses of more than 1% BW on endurance performance.
- And finally, as pointed out in the review article, there is still an information void on the impact of dehydration on physiologic recovery, including such peripheral issues as glycogen replacement, which could be magnified in multi day (or stage) events.
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
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.
- Caffeine - if you are a regular, daily caffeine user, your body will adapt to its
diuretic (water losing) effects. On the other hand, if you have been caffeine free for 5
days, and then drink the equivalent of 6 cups of coffee (642 mgs of caffeine) over a 24 hour period,
you will induce a negative fluid balance of nearly 0.8 kg (equivalent to 3 cups of water).
- Alcohol - this will decrease ADH secretion, a hormone that aids in water retention in
the kidneys, and result in an increase loss of water via the kidneys. For every 2
drinks, you should take an additional 1 cup of fluid per day.
- Environmental factors - heat, humidity, and altitude
- drink 20 oz of cool water 2 hours before exercise
- 8 to 16 oz 30 minutes before
- and then 4 to 8 oz every 15 minutes on the bike
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.
Q. Do electrolyte drinks (those containing minerals
such as sodium and potassium) provide an advantage over pure water alone?
- Hydrate before, during, and after the ride - force yourself to drink as thirst
alone will not reflect complete rehydration, so learn to drink before you are
thirsty. Using a CamelBak or similar device on long rides will eliminate worries
about stopping and possibly losing your group. Watch the color of your urine, if you are
doing a good job on replacement it should be colorless.
- Don't skimp when using a sports drink - don't assume that because they contain
electrolytes and carbohydrates you don't need to drink as much. As the sweet taste often
keeps you from drinking, dilute it or take an extra bottle of plain water to alternate.
- Keeping liquids cool has been shown to increase intake on a ride - either add
ice the day of the ride or freeze half a water bottle of fluid the night before and top
it off with water from the tap or extra sports drink just before the ride.
- Weigh yourself before and after the ride - most of your weight loss will be
fluid (2 pounds equals 1 quart or "a pint's a pound"). A drop of a pound or two
won't impair performance, but any more and you need to reassess your personal
hydration program. A gain of more than 1 or 2 pounds suggests you are over
compensating. This is an especially important strategy in hot weather where fluid
losses can easily exceed several quarts an hour.
- Wear the right clothing - light colored to reflect heat and a loose
weave jersey to help keep you cool and lessen sweat losses.
- Wear your helmet - modern well vented helmets funnel the wind onto your head
and are actually cooler than your bare head. And the helmet material will insulate
your head from the heat of the sun's rays.
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
is "no". There is:
- No evidence that
increasing fluid intake decreases kidney disease.
- 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)
- No evidence that increasing fluid
intake improves skin tone and luster.
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
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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