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High energy deficit in an ultraendurance athlete in a 24-hour
ultracycling race
Raúl Bescós, PhD, Ferran A. Rodríguez, MD, PhD, Xavier Iglesias, PhD, Adolfo Benítez, MSc, Míchel Marina, PhD,
Josep M. Padullés, PhD, Priscila Torrado, MSc, Jairo Vázquez, MSc, and Beat Knechtle, MD, PhD
This case study examined the nutritional behavior and energy balance
in an official finisher of a 24-hour ultracycling race. The food and bever-
ages consumed by the cyclist were continuously weighed and recorded
to estimate intake of energy, macronutrients, sodium, and caffeine. In
addition, during the race, heart rate was continuously monitored. Energy
expenditure was assessed using a heart rate–oxygen uptake regression
equation obtained previously from a laboratory test. The athlete (39 years,
175.6 cm, 84.2 kg, maximum oxygen uptake, 64 mL/kg/min) cycled
during 22 h 22 min, in which he completed 557.3 km with 8760 m
of altitude at an average speed of 25.1 km/h. The average heart rate
was 131 beats/min. Carbohydrates were the main macronutrient intake
(1102 g, 13.1 g/kg); however, intake was below current recommenda-
tions. The consumption of protein and fat was 86 g and 91 g, respectively.
He ingested 20.7 L (862 mL/h) of fluids, with sport drinks the main fluid
used for hydration. Sodium concentration in relation to total fluid intake
was 34.0 mmol/L. Caffeine consumption over the race was 231 mg
(2.7 mg/kg). During the race, he expended 15,533 kcal. Total energy
intake was 5571 kcal, with 4058 (73%) and 1513 (27%) kcal derived
from solids and fluids, respectively. The energy balance resulted in an
energy deficit of 9915 kcal.
Ultraendurance competitions are held as solo events in an
attempt to challenge the limits of human endurance.
ese events are defi ned as an endurance performance
of more than 6 hours (1). Careful race preparation is
mandatory for all competitors, and the successful accomplish-
ment of such a race depends on many factors, among which
nutrition is one of the most important. Adequate nutritional in-
take is important not only to maintain or improve performance
but also to avoid disturbances in the athletes’ health. Several
studies have reported on the nutritional behavior and demands
of cyclists during ultraendurance competitions of several days,
such as the Race Across America (2, 3). However, only one
case study published in the 1980s has examined the nutrition-
al demands and nutritional behavior of cyclists during events
lasting for 24 hours (4). e popularity of these competitions
during the past few years has become evident, and with the
increase in the number of competitions, information is needed
on the nutritional demands in these events (5). Accordingly, the
aim of this case study was to describe the nutritional behavior
From Instituto Nacional de Educación Física de Barcelona, Spain (Bescos,
Rodríguez, Iglesias, Benítez, Marina, Padullés, Torrado, Vázquez); and
Gesundheitszentrum St. Gallen, St. Gallen, Switzerland (Knechtle).
Corresponding author: Raúl Bescós García, Instituto Nacional de Educación
Física de Barcelona (INEFC), Av. de l´Estadi s/n, 08038 Barcelona, Spain (e-mail:
raul.bescos@gmail.com).
(ingestion of macronutrients, fl uids, sodium, and caff eine) and
to assess the energy balance of one cyclist during a 24-hour
ultracycling race.
METHODS
Participant and race
e physical and physiological characteristics of the cy-
clist are shown in Table 1. Before testing, the participant was
informed of the risks associated with the study and provided
written informed consent in accordance with the local ethical
committee.
e race consisted of completing the greatest possible dis-
tance during 24 hours (from 7:00 on July 3, 2009, through
Table 1. Physical and physiological characteristics of the cyclist
Variable Value
Age (years) 39
Height (cm) 175.6
Body mass (kg) 84.2
Body mass index (kg/m2) 26.4
Body fat (%) 11.6
VO2max ( mL/kg/min) 64.0
Wmax (watts/kg) 5.5
HRmax (beats/min) 199
VT HR (beats/min) 159
RCP HR (beats/min) 173
VO2max indicates maximum oxygen uptake; Wmax, maximum power output relative
to body mass in watts; HRmax, maximum heart rate; VT HR, heart rate at ventilatory
threshold; RCP HR, heart rate at respiratory compensation point.
124 Proc (Bayl Univ Med Cent) 2012;25(2):124–128
7:00 on July 4) on a closed-road circuit that was 3790 m in
length and 60 m of elevation per lap. e time and velocity to
complete each lap was recorded. During the race, the ambient
air temperature was 27.5ºC (range, 24.6–31.0); the relative
humidity, 53.9% (range, 33.0–72.0); and the mean velocity of
wind, 1.7 m/s (range, 0.6–3.0).
Preliminary testing
One week before the competition, the athlete reported to a
physiology laboratory under controlled conditions (22 ± 1ºC,
40%–60% relative humidity, 760–770 mm Hg) to perform
an incremental maximum oxygen uptake (VO2max) test. e
test was performed on an electronically braked cycle ergometer
(Excalibur Sport, Lode, e Netherlands) modifi ed with clip-
on pedals. e exercise protocol started at 25 watts and was
increased 25 watts every minute until exhaustion. e number
of revolutions was individually chosen in the range of 70 to
100 revolutions per minute. During the test, the respiratory
response was measured, breath by breath, using a computer-
ized gas analyzer (Cosmed Quark PFT Ergo, Italy). Before the
test, the ambient condition was measured and the gas analyzers
and inspiratory fl owmeter were calibrated using high-precision
calibration gases (16.00 ± 0.01% O2 and 5.00 ± 0.01% CO2;
Scott Medical Products, USA). After the test, all respiratory
data were averaged at 30-second intervals to determine VO2max,
taken as the highest average value. In addition, heart rate (HR)
was continuously recorded using a portable HR monitor (Polar
RS800 SD, Finland). HRmax was defi ned as the HR at the point
of exhaustion.
Data collection during the race
Within the circuit, all the athletes had a box where they
could stop during racing to recover, sleep, eat, and repair bicycle
breakdowns. In the other points of the circuit, riders could
not receive any assistance. Nutritional data were collected by
four trained investigators who remained in the box of the rider,
weighing and recording all the food and fl uid ingested. Nutri-
tional data were analyzed for nutrient composition using nu-
tritional software (CESNID 1.0, Barcelona University, Spain).
Information about the nutritional content of foods not available
in the computer program was obtained from the manufacturer.
All the food was weighed on a digital scale (Soehnle 8020,
Spain) with a precision of 1 g increments up to 1 kg and 2 g
between 1 and 2 kg. We divided the input of energy derived
from solid and liquid food, classifi ed as products that did not
need mastication.
In addition, during the competition, HR was continuously
monitored, beat by beat, using a portable HR monitor (Polar
RS800 SD, Finland) that was properly programmed with gen-
der, age, and weight following the manufacturer’s instruction.
Later, all HR data were averaged at 10-second intervals. e
linear relationship between HR and VO2 obtained during the
laboratory test was used to estimate the oxygen costs and energy
expenditure of racing (r2 = 0.988). Taking the average of HR
during the competition and the maximal HR obtained during
the laboratory test, we calculated the ratio of HRmean/HRmax.
RESULTS
e cyclist successfully completed the race, cycling for
22 h 22 min, in which he completed 557.3 km with 8760 m
of altitude at an average speed of 25.1 km/h, fi nishing in third
place. He reported no gastrointestinal disturbances during the
race. e average HR during the event was 131 beats/min, with
a ratio of HRmean/HRmax of 0.69. He made a total of seven stops
lasting 1 h 38 min. During the race, he expended 15,533 kcal
of energy, corresponding to 647 kcal/hour.
As shown in Table 2, during the event, solid foods provided
73% (4058 kcal) of the total energy, and the remaining 27%
(1513 kcal) was provided by fl uids such as sport drinks. Car-
bohydrates were the main macronutrient he ingested (1102 g;
13.1 g/kg). Overall consumption of fl uids and sodium dur-
ing the event was 20.7 L (862 mL/h) and 16,182 mg (34.0
mmol/L), respectively. Fluids comprised 86% (13,878 mg)
of the total sodium intake, and solids comprised 14% (2355
mg). During the second half of the event (7–19 h), the cyclist
increased consumption of caff einated drinks, with total caf-
feine intake of 231 mg (2.7 mg/kg); consumed low amounts of
branched chain amino acids in pill form during the rest periods;
and ingested one ibuprofen pill after 9 h of competition and
two aspirin pills at 18 h.
After the event, the athlete lost 2.6 kg of total body mass
(prerace, 84.2 kg; postrace, 81.6 kg). A total defi ciency of
9915 kcal resulted after the race, so that a higher proportion
(64%) of energy was obtained from endogenous fuel stores.
DISCUSSION
e main fi nding of this study was the high energy defi cit
of this cyclist. He ingested only 36% of the energy expended
through the event, thus providing the remaining 64% of the
energy from endogenous fuel stores. To the best of our knowl-
edge, these data represent the highest energy defi cit reported in
ultraendurance events of 24 hours or longer. Previous studies
showed an energy intake and expenditure ratio between 0.50
and 0.65 (2, 4, 6).
However, it is worth mentioning that the method used in
this study to estimate energy expenditure (relationship between
HR and VO2) has several limitations. For instance, during
longer events, HR can be infl uenced by environmental condi-
tions such as temperature and humidity, which can favor dehy-
dration and an increase of HR without associated changes in VO2
(7). Currently, the method of doubly labeled water is considered
the reference method to estimate energy expenditure. Another
feasible method to estimate energy expenditure in cycling is the
analysis of power output (8). However, neither of these methods
was at our disposal during the current study. For this reason and
similar to other recent studies (6, 9–11), we estimated energy
expenditure using the HR-VO2 method. Compared with the
doubly labeled water method, this method is inexpensive and
easy to perform. Additionally, monitoring of HR also provides
information on the amount of time spent at diff erent levels of
exercise intensity, which may also be useful for the assessment of
physical activity rather than energy expenditure. Furthermore, it
has been reported that energy expenditure estimated using the
High energy deficit in an ultraendurance athlete in a 24-hour ultracycling raceApril 2012 125
Baylor University Medical Center Proceedings Volume 25, Number 2126
HR method compared with the
method of doubly labeled water
is overestimated by ~10% (12). If
we accounted for this by reducing
the energy expenditure estimated
in this study by 10%, the energy
defi cit would be decreased only
4%, from 64% to 60%. ere-
fore, although the doubly labeled
water method could be used
under fi eld conditions, the high
cost and the inability to obtain
an activity pattern does not always
make it ideal.
Based on the athlete’s aver-
age intensity of 69% HRmax, it
is estimated that approximately
two thirds of the total energy re-
quired was met by fat oxidation,
with carbohydrate oxidation pro-
viding one third (13). However,
fat oxidation is not a limitation
for providing fuel during longer
events (13, 14). e estimation of
anthropometric characteristics in
the current athlete indicated that
he had ~9.8 kg of subcutaneous
adipose tissue that could provide
>88,000 kcal. Based on that, the
athlete should consume a high
amount of carbohydrates dur-
ing the event due to his limited
glycogen stores (13). e recom-
mended amount of carbohydrate
intake to optimize the oxidation
rates has been reported to be be-
tween 1.0 and 1.2 g/min (15). e
current athlete ingested amounts
of carbohydrates below these
recommendations during three-
quarters of the event; only during
the last 6 h, when fatigue symp-
toms were more pronounced and
the glycogen stores were possibly
depleted, did he meet the carbo-
hydrate consumption threshold of
>1.0 g/min.
Additionally, although protein
is not considered a primary energy
source for athletes, it has been sug-
gested to play an important role
during longer events. An adequate
ratio of carbohydrate/protein may
reduce a negative protein balance
(16, 17) and may enhance aero-
bic endurance performance (18).
Table 2. Nutritional analysis of foods and fluids ingested by the cyclist during the event
Variable 0–6 h 6–12 h 12–18 h 18–24 h Total
Ingested
Solid food (g)
Pasta with olive oil – 224 133 200 557
Sport bars 252 137 101 65 555
Fruit – 513 – 243 756
Chicken – – – 70 70
Cured ham – – 43 – 43
Bread – – 40 – 40
Fluids (mL)
Sport drinks (0% carbohydrate) – – 2292 5714 8006
Sport drinks (1.4% carbohydrate) 1806 1830 1279 – 4915
Sport drinks (7% carbohydrate) – – – 3080 3080
Water 1241 932 – – 2173
Caffeinated drinks – 250 330 580 1160
Water in food 8 601 178 365 1152
Juice – 250 – – 250
Supplementation and medication
Branched chain amino acids (mg) – – 1000 1500 2500
Ibuprofen (mg) – – 600 – 650
Aspirin (mg) – – – 200 200
Analysis
Energy (kcal)
Solids 1357 918 675 1108 4058
Fluids 121 211 388 793 1513
Total 1478 1129 1063 1901 5571
Carbohydrates (g)
Solids 260 164 106 192 722
Fluids 28 52 102 198 380
Total 288 216 208 390 1102
Percent of total energy 77.9 76.5 78.3 82.1 79.1
g/min 0.8 0.6 0.6 1.1 0.8
Protein (g)
Solids 23 19 15 29 86
Percent of total energy 6.2 6.7 5.6 6.1 6.2
Carbohydrate/protein ratio 12.5 11.4 13.9 13.4 12.8
Fat (g)
Solids 26 21 19 25 91
Percent of total energy 15.6 16.7 16.1 11.8 14.7
Caffeine (mg) – 82 35 113 231
Sodium (mg) 2201 2101 4752 7128 16,182
An optimal rate (g) between carbohydrate and protein intake
seems to be 4:1 (18). Applying these recommendations in the
present case study, and assuming that the athlete had ingested
the recommended carbohydrate rate (~1.1 g/min), protein in-
take would have had to have been ~400 g (4.7 g/kg of body
mass), representing more than threefold the actual amount of
protein intake by the cyclist during the event. Accordingly, this
amount of protein seems to be excessive and, independent of
the supposed benefi ts of carbohydrate and protein combina-
tion, it should also be taken into account that protein intake is
associated with greater satiety and a reduced ad libitum energy
intake in humans. us, higher protein consumption during
longer events can be associated with a reduction of food intake,
as well as an increase of the risk of gastrointestinal disturbances.
Further studies are needed to analyze whether an increase of
protein intake above the current recommendations (1.2 –1.7 g/
kg of body mass/day) may induce benefi ts in longer and high-
intensity sport events.
Furthermore, the hydration pattern is one of the nutritional
keys in ultraendurance events. While the current athlete ingested
the high amount of 20.7 L of fl uids during the race, the hydra-
tion strategy was not in agreement with current recommenda-
tions (19, 20). He should have prioritized the consumption of
isotonic fl uids containing carbohydrates (sucrose, maltose, or
maltodextrins) at ~3% to ~8% weight/volume during the race
(21). us, the strategy of hydration followed by the cyclist
substantially reduced the amount of carbohydrate intake. If he
had prioritized the consumption of isotonic fl uids (7% of carbo-
hydrates), he would have obtained ~900 g extra carbohydrates,
reaching values within the carbohydrate recommendations for
longer events (15).
Related to the hydration pattern, one of the most common
medical complications during long-distance events is exercise-
associated hyponatremia (22), defi ned as a serum plasma or
sodium concentration <135 mmol/L-1. To prevent exercise-
associated hyponatremia, the athlete ingested higher amounts
of sodium, mainly during the second half of the event when the
environmental conditions were harsher. Nevertheless, although
some hydration guidelines recommend consuming fl uids with a
high content of sodium (30–50 mmol/L) (21), currently there
is insuffi cient evidence to determine whether sodium intake
prevents or decreases the risk of exercise-associated hypona-
tremia (23). On the contrary, some risks of excessive sodium
supplementation in combination with overhydration have been
documented (24). ere are at least two ways to reduce the risk
of excessive fl uid retention: 1) drink only according to thirst
and 2) monitor body weight so as to avoid weight gain during
exercise. In the present study, the cyclist showed no weight
gain; he lost 2.6 kg of body mass over the race. However, in
ultraendurance events such as an Ironman triathlon, it has been
reported that part of fl uid losses, at least 2 kg, could be derived
from reduction of fat stores, skeletal muscle mass, glycogen, and
the metabolic water stored in glycogen (25, 26).
In conclusion, this case study shows one of the highest en-
ergy defi cits in the scientifi c sports literature. To minimize the
energy defi cit, athletes should receive nutritional training be-
fore the event so that the digestive system can adapt to higher
amounts of food and fl uids while physical exercise is performed.
In addition, they should begin the event with their meals and
fl uids planned and prepared beforehand according to their pref-
erences. e present fi ndings highlight the importance of the
support provided by sports dieticians and sports physiologists
in helping athletes plan and monitor their food and fl uid intake
during longer events.
Acknowledgments
is study was funded by the National Institute of Physical
Education of Barcelona, Polar Iberica, and RPM Events. e au-
thors appreciate the technical support of the Research Group of
Applied Nutrition–Department of Nutrition and Bromatology
(University of Barcelona). In addition, we are indebted to Víctor
Cervera for his support in data collection during the study.
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