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Journal Title: Journal of the American College of
Nutrition.
Volume: 30 Issue:
Month/Year: 2011Pages: 529-535
Article Author:
Article Title: Stuempfle; Race Diet of Finishers and Non-
Finishers in a 100 Mile Mountain Footrace
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Original Research
Race Diet of Finishers and Non-Finishers in a 100 Mile
(161 km) Mountain Footrace
Kristin J. Stuempfle, PhD, Martin D. Hoffman, MD, Louise B. Weschler, MAT, PT, Ian R. Rogers, MBBS, Tamara Hew-
Butler, DPM, PhD
Health Sciences Department, Gettysburg College, Gettysburg, Pennsylvania (K.J.S.), Department of Physical Medicine &
Rehabilitation, Department of Veterans Affairs, Northern California Health Care System, and University of California Davis Medical
Center, Sacramento, California (M.D.H.), Independent Researcher, Colts Neck, New Jersey (L.B.W.), Sir Charles Gairdner Hospital
and University of Western Australia, Perth, AUSTRALIA (I.R.R.), Exercise Science Program, Oakland University, Rochester,
Michigan (T.H.-B.)
Key words: ultrarunning, fuel consumption, hydration, sodium
Objective: To determine if food and fluid intake is related to completion of a 161-km ultramarathon.
Methods: Sixteen consenting runners in the Western States Endurance Run participated in the study. Race
diets were analyzed using Nutritionist Pro software. Both total intake and intake by race segment (3 total) were
evaluated.
Results: Six of 16 subjects completed the race (finishers) in 27.0 62.3 hours (mean 6SD). Non-finishers
completed 96.5 620.5 km in 17.0 63.9 h. Overall consumption rates of kilocalories, carbohydrate, fat, and
sodium were significantly greater (P,0.05) in finishers (4.6 61.7 kcal/kg/h, 0.98 60.43 g carbohydrate/kg/h,
0.06 60.03 g fat/kg/h, 10.2 66.0 mg sodium/kg/h) versus non-finishers (2.5 61.3 kcal/kg/h, 0.56 60.32 g
carbohydrate/kg/h, 0.02 60.02 g fat/kg/h, 5.2 63.0 mg sodium/kg/h). Kilocalorie, fat, fluid, and sodium
consumption rates during segment 1 (first 48 km) were significantly greater in finishers than in non-finishers.
Conclusions: Completion of this 161-km race was related to greater fuel, fluid, and sodium consumption
rates. However, intake ranges for the finishers were large, so factors other than race diet may have contributed to
the successful completion of the race.
INTRODUCTION
Ultraendurance events (as exemplified by running events 50
km and longer) have risen in popularity in recent years [1,2].
These events include running races, cycling events, distance
swims, and triathlons. One of the most challenging ultra-
endurance events is the Western States Endurance Run
(WSER), a 100-mile (161-km) footrace. Large changes in
elevation and substantial variations in temperature characterize
the race. Over a 20-year period, finish rates at WSER have
ranged from 48%to 80%, and finish times have ranged from
approximately 15.5 hours to the usual time limit of 30 hours
[3]. Exercise of this duration in various environmental
conditions creates unique physiological challenges for runners,
including optimizing fuel, fluid, and electrolyte intake.
Total energy expenditure during the WSER has been
reported to range from approximately 13,000 to 16,000 kcal
[4,5]. Consumption of exogenous fuel will help offset this
energy expenditure and may contribute to a successful race.
Carbohydrate, fat, and protein all can be used to generate
energy during an ultraendurance run, with the relative
contribution of each dependent on existing energy stores,
exercise intensity, and duration, and composition of the race
diet [6]. Carbohydrates are commonly considered to be the
most important fuel during ultraendurance exercise, and since
glycogen stores are limited, it is important that athletes
consume carbohydrates during exercise to maintain blood
glucose levels [7,8]. Although carbohydrates are the preferred
fuel, fats also are a major energy substrate during ultra-
endurance exercise [6,9]. The role of protein metabolism
Address reprint requests to: Kristin J. Stuempfle, PhD, ATC, FACSM, Gettysburg College, Department of Health Sciences, Campus Box 432, 300 North Washington St,
Gettysburg, PA 17325. E-mail: kstuempf@gettysburg.edu
Journal of the American College of Nutrition, Vol. 30, No. 6, 529–535 (2011)
Published by the American College of Nutrition
529
during ultraendurance exercise is less clear, but proteins may
be an important substrate as well [6,9].
Maintaining fluid and electrolyte homeostasis is a challenge
for ultraendurance runners. The prevailing view is that
hypohydration (water deficit .2%–3%body mass loss) [10–
12] compromises performance and increases the risk of heat
illness [11,12], although this view has been challenged [12] and
;6%body mass loss has been observed among the fastest
runners in 161-km ultramarathons [13,14]. In contrast,
hyperhydration causes a reduction in blood sodium concentra-
tion, resulting in hyponatremia [15]. This potentially life-
threatening electrolyte disorder recently was documented in an
alarming 51%of finishers at the 2008 Rio Del Lago 100 Mile
Endurance Run [13] and 30%of finishers at the 2009 WSER
[14].
Food and fluid consumption is critical for successful
completion of a 161-km footrace. Yet very little research has
addressed the quantitative race diet needs of ultraendurance
runners. Therefore, the purpose of the present study was to
document food and fluid intake during a 161-km mountain
footrace and ascertain whether this intake is related to the
ability of runners to finish the race.
MATERIALS AND METHODS
The study was set at the 2009 WSER in the Sierra Nevada
mountains of northern California. The 161-km point-to-point
race begins in Squaw Valley and ends in Auburn. The course is
primarily on single-track mountain trails with more than 5500
m of cumulative ascent and 7000 m of cumulative descent.
Nearby temperature during the race ranged from 48Cto378C.
Twenty-four aid stations on the course were stocked with
various foods, fluids, and electrolyte capsules.
Institutional Review Board approval was granted for this
study, and all subjects signed an informed consent document.
Subjects were recruited via e-mail prior to the race. Height was
measured during race registration several days before the race.
Weight was measured in the hour prior to race start, at 48 km,
at 100 km, and immediately postrace using a WW42D
impedance scale (Weight Watchers, New York, NY). Subjects
were wearing running shoes and running attire and were not
holding bottles or other items while being weighed. Body mass
index (BMI) was calculated from the measured height and
prerace body mass.
The subjects were not told what food, fluid, or electrolyte
capsules to consume during the race. A multipronged approach
with built-in redundancy maximized accurate accounting of
food, fluid, and electrolyte capsule intake:
1. Approximately 1 week prerace, subjects submitted via e-mail
a plan of the food, fluid, and electrolyte capsules they
intended to consume during the race. Subjects were
interviewed about their submitted plan during race registra-
tion to clarify any questions the investigators had about their
nutrition plan and to familiarize the subjects with the detail
that would be expected regarding brand, flavor, and amount
of each consumed item. Volumes of bottles and hydration
pack bladders were established.
2. At 48 km, 100 km, and immediately postrace, subjects were
interviewed (food, fluid, and electrolyte capsule intake;
presence of nausea and/or vomiting) and food wrappers were
collected.
3. Approximately 1 week postrace, the investigators sent the
subjects their race diet logs via e-mail so that the subjects
could review them for completeness and accuracy.
4. Brand, flavor, and amount of each item consumed were
recorded.
Nutritionist Pro (Axxya Systems, Stafford, TX) software
was used to analyze the nutritional composition of the foods,
fluids, and electrolyte capsules consumed. Nutritional infor-
mation for items not included in Nutritionist Pro was obtained
from the manufacturer and added to the software database.
Diets were analyzed for kilocalories, macronutrients, and
micronutrients.
Total intake for the race was determined, as well as intake/h
and intake/kg/h. Intake/kg/h was the focus of comparisons
between finishers and non-finishers since it normalized for
body mass and rate of intake. To evaluate changes in intake
over time, the data also were analyzed by race segment. The 3
segments were defined by the aid stations at 48 km and 100
km, where the subjects were weighed and interviewed and
divided the total race distance into approximate thirds.
Hereafter, these are referred to as segments 1, 2, and 3.
Unpaired ttests were used to evaluate differences between
finishers and non-finishers and between runners with nausea
and/or vomiting and runners without nausea and/or vomiting.
Prerace and postrace comparisons for finishers and non-
finishers were made using paired ttests. Repeated-measures
analysis of variance determined differences by segment for the
finishers, with follow-up Scheffe post hoc tests. Statistical
significance was set at P,0.05. Power was computed
retrospectively at 80%.
RESULTS
Six of 16 (38%; 4 male, 2 female) subjects completed the
race (finishers) in 27.0 62.3 h (mean 6SD). Non-finishers (10
out of 16; 62%; 8 male, 2 female) completed 96.5 620.5 km in
17.0 63.9 h (Table 1). Among the non-finishers, 10 runners
completed the first segment of the race, 6 completed the second
segment, and none completed the third race segment.
Retrospective power analysis suggested that these sample sizes
may have been insufficient to detect statistically significant
differences between the finishers and non-finishers. Overall
finish rate for the race was 60%. Finishers did not differ
530 VOL. 30, NO. 6
Ultramarathon Race Diet
significantly from non-finishers in age, years running, number
of ultra marathons completed, or number of 100-mile races
completed.
Finishers lost significant body mass prerace (68.8 615.8
kg) to postrace (66.7 615.4 kg; Table 2). Non-finishers lost
significant body mass prerace (74.3 613.2 kg) to the last
checkpoint before dropping out (72.0 612.1 kg). BMI, prerace
and postrace body mass, change in body mass, and rate of body
mass change did not differ significantly between finishers and
non-finishers.
Subjects consumed a variety of ordinary foods (soups,
sandwiches, cookies, fruit, candy, potato chips, boiled potatoes,
etc.) and foods marketed specifically to exercising athletes
(energy bars, energy gels, etc.). They drank both water and
assorted sports drinks. Eighty-one percent of subjects (100%of
finishers, 70%of non-finishers) consumed electrolyte capsules.
Table 3 summarizes food intake during the race. Overall,
finishers consumed 8228 kcal during the race, consisting of
81.5%carbohydrate, 11.9%fat, and 6.6%protein, compared
with non-finishers who consumed 3106 kcal, consisting of
88.3%carbohydrate, 6.2%fat, and 5.4%protein. Rate of
caloric consumption was significantly greater in finishers (4.6
61.7 kcal/kg/h) compared with non-finishers (2.5 61.3 kcal/
kg/h). Finishers (0.98 60.43 g/kg/h) consumed carbohydrates
at a significantly greater rate compared with non-finishers (0.56
60.32 g/kg/h). Rate of fat consumption also was significantly
greater in finishers (0.06 60.03 g/kg/h) versus non-finishers
(0.02 60.02). Rate of protein consumption was similar in
finishers and non-finishers.
Food intake for each segment is summarized in Table 4.
During segment 1, finishers (4.3 61.6 kcal/kg/h) consumed
energy at a significantly higher rate compared with non-
finishers (2.7 61.2 kcal/kg/h). Rate of fat consumption also
was significantly greater during segment 1 in finishers (0.05 6
0.04) versus non-finishers (0.01 60.02). Comparing food
intake over segments in the finishers indicated the rate of
energy consumption in segment 3 (3.7 61.3 kcal/kg/h) was
significantly less than during segment 2 (6.1 62.8 kcal/kg/h).
Table 5 summarizes total fluid and sodium consumption,
and Table 6 presents this information by segment. Finishers
consumed a total of 19.8 L of fluid compared with non-
finishers who consumed 10.8 L. Overall fluid intake rate did
not differ significantly between finishers (11.0 64.3 ml/kg/h)
and non-finishers (8.6 63.1 ml/kg/h). During segment 1,
finishers (14.0 64.4 ml/kg/h) consumed fluid at a significantly
higher rate compared with non-finishers (9.2 62.7 ml fluid/kg/
h). Comparing fluid intake over segments in the finishers
indicated consumption rate in segment 3 (8.9 64.1 ml/kg/h)
was significantly less than during segment 1 (14.0 64.4 ml/kg/
h).
Finishers consumed a total of 17.9 g of sodium compared
with non-finishers who consumed 6.2 g. Rate of sodium
consumption was greater in finishers (10.2 66.0 mg/kg/h)
compared with non-finishers (5.2 63.0 mg/kg/h). During
segment 1, finishers (9.3 66.0 mg/kg/h) consumed sodium at a
significantly greater rate compared with non-finishers (4.8 6
1.7 mg sodium/kg/h).
Seventy five percent of subjects (67%of finishers, 80%of
non-finishers) experienced nausea and/or vomiting. There were
no statistically significant differences in rate of food, fluid, or
sodium intake in runners with nausea and/or vomiting and
runners without nausea and/or vomiting.
DISCUSSION
On average, finishers in the present study consumed fuel at
a greater rate than non-finishers, and this difference was
apparent from race start. Overall rate of fluid consumption was
similar between finishers and non-finishers, but finishers
consumed fluid at a greater rater in the first segment of the
race. Finishers consumed sodium at a greater rate than non-
finishers, both overall and in the early part of the race. It is
important to note, however, that the ranges of fuel, fluid, and
sodium intake in finishers were large, consistent with factors
other than race contributing to successful completion of the
race.
Energy expenditure during the WSER previously was
determined to be 13,000–16,000 kcal by indirect calorimetry
and doubly-labeled water [4,5]. The finishers in the current
Table 1. Demographic Comparison of Finishers and Non-
finishers
a
Variable
Finishers
(n ¼6)
Non-finishers
(n ¼10)
Age (y) 47.2 64.8 43.4 65.6
Years running 22.2 613.0 14.4 610.4
Previous ultramarathons
completed
17.5 623.8 23.4 633.6
Distance completed during
race (km)
161.0 60.0 96.5 620.5
*
Running duration during race (h) 27.0 62.3 17.0 63.9
*
a
Data are presented as mean 6SD.
*P,0.05 between finishers and non-finishers.
Table 2. Body Mass Index (BMI) and Body Mass in Finishers
and Non-finishers
a
Variable Finishers (n ¼6) Non-finishers (n ¼10)
BMI 22.9 62.2 24.4 63.2
Start mass (kg) 68.8 615.8 74.3 613.2
End mass (kg) 66.7 615.4
*
72.0 612.1
*
DMass (kg) 2.0 61.2 2.4 61.5
%Mass D3.0 61.9 3.0 61.7
DMass (kg)/h 0.07 60.05 0.16 60.15
a
Data are presented as mean 6SD.
*P,0.05 prerace to postrace.
JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION 531
Ultramarathon Race Diet
study consumed only 8200 kcal, or 51%–63%of estimated
expenditure, so caloric needs were partially met from existing
carbohydrate and fat stores. Although it is difficult to establish
guidelines for caloric consumption per unit body mass per unit
time due to differences among events, environmental condi-
tions, and individuals, it has been suggested that ultraendurance
athletes should consume 4–6 kcal/kg/h for optimal performance
[6,16]. The energy consumption for the finishers (4.6 kcal/kg/h)
Table 3. Race Diet in Finishers and Non-finishers
a
Variable Finishers (n ¼6) Non-finishers (n ¼10)
Kcal 8228.3 62377.0 (5498.0–11,185.0) 3106.3 61545.3* (902.0–5057.0)
Kcal/h 308.2 699.8 (196.5–444.2) 185.2 691.3* (54.7–335.3)
Kcal/kg/h 4.6 61.7 (3.2–7.6) 2.5 61.3* (0.8–5.5)
%Carbohydrate 81.5 610.6 (71.1–98.4) 88.3 610.1 (71.3–100.0)
Carbohydrate (g) 1751.9 6658.2 (999.1–2367.0) 697.0 6394.4* (227.0–1257.0)
Carbohydrate (g/h) 65.8 627.0 (36.0–102.1) 41.5 623.2 (13.8–83.8 )
Carbohydrate (g/kg/h) 0.98 60.43 (0.58–1.70) 0.56 60.32* (0.19–1.25)
%Fat 11.9 68.0 (1.1–23.8) 6.2 66.2 (0.0–17.4)
Fat (g) 98.1 653.0 (11.7–148.3) 19.4 621.1* (0.0–68.7)
Fat (g/h) 3.6 61.9 (0.4–5.6) 1.3 61.4* (0.0–3.7)
Fat (g/kg/h) 0.06 60.03 (0.01–0.09) 0.02 60.02* (0.00–0.06)
%Protein 6.6 63.9 (0.1–11.1) 5.4 66.2 (0.0–21.4)
Protein (g) 131.2 679.0 (10.7–228.0) 43.0 656.7* (0.0–188.8)
Protein (g/h) 4.9 62.8 (0.4–8.0) 2.4 62.6 (0.0–8.6 )
Protein (g/kg/h) 0.08 60.05 (0.01–0.12) 0.04 60.04 (0.00–0.14)
a
Data are presented as mean 6SD (range).
*P,0.05 between finishers and non-finishers.
Table 4. Race Diet by Segment in Finishers and Non-finishers
a
Variable Finishers Non-finishers
Kcal/kg/h
Segment 1 4.3 61.6 (1.6–5.9) 2.7 61.2* (0.9–5.0)
Segment 2 6.1 62.8 (3.1–10.6) 3.3 62.3 (0.7–6.8)
Segment 3 3.7 61.3** (2.0–5.9) —
%Carbohydrate
Segment 1 84.8 611.3 (69.7–96.8) 91.9 68.9 (78.4–100.0)
Segment 2 81.2 612.7 (63.3–98.4) 82.3 616.1 (61.2–100.0)
Segment 3 81.5 614.7 (58.7–99.8) —
Carbohydrate (g/kg/h)
Segment 1 0.9 60.4 (0.4–1.4) 0.6 60.3 (0.2–1.2)
Segment 2 1.3 60.7 (0.6–2.5) 0.7 60.6 (0.2–1.2)
Segment 3 0.8 60.3 (0.4–1.4) —
%Fat
Segment 1 10.6 68.5 (2.7–24.3) 4.0 66.1 (0.0–17.4)
Segment 2 12.0 610.6 (0.8–30.7) 9.0 69.5 (0.0–23.2)
Segment 3 11.3 69.3 (0.1–26.3) —-
Fat (g/kg/h)
Segment 1 0.05 60.04 (0.01–0.10) 0.01 60.02* (0.00–0.06)
Segment 2 0.07 60.05 (0.00–0.16) 0.03 60.03 (0.00–0.06)
Segment 3 0.05 60.05 (0.00–0.12) —
%Protein
Segment 1 4.6 63.9 (0.5–10.4) 4.1 66.3 (0.0–20.0)
Segment 2 6.8 64.0 (0.8–10.6) 8.7 68.5 (0.0–21.4)
Segment 3 7.2 66.1 (0.1–15.0)
Protein (g/kg/h)
Segment 1 0.05 60.06 (0.01–0.15) 0.02 60.04 (0.00–0.10)
Segment 2 0.10 60.07 (0.01–0.19) 0.07 60.06 (0.00–0.16)
Segment 3 0.07 60.06 (0.00–0.16) —
a
Data are presented as mean 6SD (range).
*P,0.05 between finishers and non-finishers.
** P,0.05 between segment 2 and segment 3.
532 VOL. 30, NO. 6
Ultramarathon Race Diet
in this race fell within these guidelines, whereas the non-
finishers (2.5 kcal/kg/h) fell short. However, it should be noted
in Table 3 that the intake rate for the finishers ranged from 3.2–
7.6 kcal/kg/h, which is outside both the lower and upper ends
of the recommended range.
The average rate of fuel consumption of finishers in this
study (4.6 kcal/kg/h) is remarkably similar to that reported for
finishers of the Vermont 100 Mile Endurance Run (3.3 kcal/kg/
h and 4.0 kcal/kg/h), a comparable mountainous trail race
[17,18]. In contrast, a case study of a 161-km track run (7.8
kcal/kg/h) [19] and a 172-km treadmill run (3.1 kcal/kg/h) [20]
revealed both higher and lower fuel intake rates compared with
the finishers in the current study. It is evident that
ultramarathons can be finished through a large range of fuel
consumption rates.
Carbohydrates are considered to be the most important fuel
during ultraendurance exercise, and since glycogen stores are
limited to approximately 2000 kcal, it is essential that athletes
consume primarily carbohydrates in the race diet [7,8]. Both
finishers (81.5%carbohydrate, 11.9%fat, 6.6%protein) and
non-finishers (88.3%, 6.2%fat, 5.4%protein) in this study
consumed a carbohydrate-rich race diet. This race diet
composition is similar to previous reports for ultraendurance
runners [17,18,21]. It has been recommended that ultra-
endurance athletes consume 1.0–1.5 g/kg/h of carbohydrate
during exercise [6,8]. In this study, finishers (0.98 g/kg/h)
consumed carbohydrates at a significantly greater rate than
non-finishers (0.56 g/kg/h), and their consumption rate fell
approximately within these recommendations. However, the
range for finishers was large (0.58–1.7 g/kg/h), indicating that a
rate of carbohydrate consumption below the recommended
guidelines does not prevent race completion. The average rate
of carbohydrate intake for finishers in this study is quite similar
to the rate reported for the Vermont 100 Mile Endurance Run
(0.81 g/kg/h) [18].
Although carbohydrates are the preferred fuel during
ultraendurance exercise, fats also are a significant source of
energy [6,9]. In contrast to limited carbohydrate stores, adipose
tissue triglyceride theoretically provides sufficient energy for
about 5 days of continuous running [9]. Fat oxidation provides
a significant contribution to energy expenditure during low-
and moderate-intensity exercise and becomes increasingly
important as exercise duration increases [22]. In the present
study, the rate of fat consumption was significantly greater in
finishers (0.06 g/kg/h) versus non-finishers (0.02 g/kg/h). The
finishers’ fat consumption rate was similar to that previously
reported for finishers in the Vermont 100 Mile Endurance Run
(0.08 g/kg/h) [18].
The role of protein metabolism during ultraendurance
exercise is not clear [6,9]. However, as glycogen stores
become depleted during prolonged exercise, protein may
become an important fuel substrate [6,9]. In this race, the rate
of protein consumption did not differ between finishers and
non-finishers. The average rate of protein intake for finishers in
this study (0.08 g/kg/h) was very similar to the rate reported for
Table 5. Fluid and Sodium Consumption in Finishers and Non-finishers
a
Variable Finishers (n ¼6) Non-finishers (n ¼10)
Fluid (L) 19.8 66.8 (8.3–25.9) 10.8 65.2* (3.7–19.6)
Fluid (ml/h) 747.7 6282.9 (278.4–978.4) 620.5 6197.8 (222.3–858.7)
Fluid (ml/kg/h) 11.0 64.3 (6.1–16.3) 8.6 63.1 (3.0–12.9)
Sodium (g) 17.9 610.1 (8.3–35.7) 6.2 63.5* (2.7–13.5)
Sodium (mg/h) 671.1 6378.5 (313.9–1258.5) 370.3 6177.1* (163.5–617.5)
Sodium (mg/kg/h) 10.2 66.0 (4.4–17.7) 5.2 63.0* (2.2–10.6 )
a
Data are presented as mean 6SD (range).
*P,0.05 between finishers and non-finishers.
Table 6. Fluid and Sodium Consumption by Segment in Finishers and Non-finishers
a
Variable Finishers Non-finishers
ml fluid/kg/h
Segment 1 14.0 64.4 (8.2–17.7) 9.2 62.7* (4.7–13.0)
Segment 2 11.5 65.6 (4.8–17.2) 12.1 65.2 (5.7–19.3)
Segment 3 8.9 64.1** (4.1–14.0) —
Sodium (mg/kg/h)
Segment 1 9.3 66.0 (4.2–19.4) 4.8 61.7* (3.0–7.9)
Segment 2 12.1 68.1 (3.9–24.8) 7.8 64.5 (2.8–13.8)
Segment 3 9.4 64.8 (4.0–15.1) —
a
Data are presented as mean 6SD (range).
*P,0.05 between finishers and non-finishers.
** P,0.05 between segment 1 and segment 3.
JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION 533
Ultramarathon Race Diet
finishers of the Vermont 100 Mile Endurance Run (0.07 g/kg/
h).
Maintaining fluid and electrolyte homeostasis during an
ultraendurance race is a challenge for athletes. These races
typically involve variations in temperature, elevation, wind,
and sun exposure. Hypohydration is the most common disorder
during ultraendurance events [6], but hyponatremia is among
the most serious [15]. Hyponatremia primarily results from
hyperhydration, which can be caused by the overconsumption
of fluids and/or the inappropriate release of arginine vasopres-
sin [15]. The potential contribution of sodium loss to the
development of hyponatremia has yet to be demonstrated [15].
It is difficult to establish universal guidelines for fluid and
electrolyte replacement during ultraendurance exercise because
sweat rates and sweat composition vary greatly among
individuals and depend on environmental conditions, exercise
intensity and duration, level of acclimatization, diet, and
genetic predisposition [11]. For instance, sweat rates have been
reported to vary from 0.5 to 2.0 L/h [11], and sweat sodium
concentration averages ;35 mEq/L with a range of 10–70
mEq/L [23]. Current fluid replacement recommendations from
the International Marathon Medical Directors Association are
to drink to thirst (ab libitum), because drinking to thirst will
protect athletes from the hazards of both hypohydration and
hyperhydration by providing real-time feedback on plasma
osmolality [24]. However, the marketing of sports drinks
continues to promote overdrinking [25]. A recent study [26] of
runners in 5- to 21-km races indicated that 56%drink only
when thirsty. However, 37%drink according to a preset
schedule, and 9%drink as much as possible during a race. Both
of the latter groups are at risk for hyperhydration and the
development of hyponatremia. It has been recommended that
ultraendurance athletes consume 1 g sodium/h [6,8].
It has been suggested that athletes who gain body mass
during endurance exercise are overhydrated, those with body
mass loss 3%are euhydrated, and those with body mass loss
.3%are dehydrated [10]. In the present study, both finishers
(2.0 61.2 kg) and non-finishers (2.4 61.5 kg) lost
significant body mass prerace to postrace. The average
percentage body mass change for both groups was 3.0%,
suggesting that these runners were essentially euhydrated and
had maintained fluid homeostasis [10]. The overall rate of fluid
consumption was similar between the finishers and the non-
finishers, and the average rate of fluid consumption for the
finishers (11.0 ml/kg/h) was comparable to the rate reported for
the Vermont 100 Mile Endurance Run (9.8 ml/kg/h [17] and
11.1 ml/kg/h [18]). As was the case with fuel consumption, the
range of fluid intake rates among the finishers of the current
race was large (6.1–16.3 ml/kg/h).
Electrolyte capsules were available at aid stations in the
current study, and their consumption was widespread. Eighty-
one percent of subjects (100%of finishers, 70%of non-
finishers) consumed electrolyte capsules as part of their race
diet. Overall rate of sodium consumption was significantly
greater in finishers (10.2 66.0 mg/kg/h) compared with non-
finishers (5.2 63.0 mg/kg/h). It is not known if this greater rate
of sodium consumption in finishers was secondary to the
greater fuel consumption rate, increased use of electrolyte
capsules, and/or increased sodium palatability. Rate of sodium
consumption for the finishers was lower than the recommended
1 g sodium/h [6,8] but was similar to the rate reported for
Vermont 100 Mile Endurance Run finishers (9.4 mg/kg/h).
Similar to fuel and fluid consumption, finishers in the current
study had a large range of sodium intakes (4.4–17.7 mg/kg/h).
The role of sodium supplementation during ultraendurance
exercise warrants further investigation.
In addition to examining overall rates of fuel, fluid, and
sodium consumption, we also investigated intake rates by race
segment. Segment 1 (0–48 km) was at the highest altitude and
was completed under relatively cool conditions. Segment 2
(48–100 km) was regarded as the most difficult part of the
course because of the greatest altitude changes and the hottest
temperatures. Segment 3 (100–161 km) was at the lowest
altitude and was generally completed under cooler and dark
conditions. During segment 1, finishers consumed fuel, fluid,
and sodium at significantly greater rates than non-finishers did
(Tables 4 and 6 ). The rate of fuel and fluid consumption
decreased significantly for finishers during the third segment
compared with earlier segments (Tables 4 and 6). This may
have been the result of physical fatigue, sleep deprivation,
flavor fatigue, gastrointestinal distress [16], or the difficulty of
completing this segment in the dark [27].
Nausea and/or vomiting are common challenges for ultra-
endurance runners [16]. A previous study at WSER [28]
revealed that 37%of finishers and 40%of non-finishers
experienced nausea and/or vomiting, and among the non-
finishers, this was the most common reason for dropping out of
the race. In the present study, 75%of subjects (67%of
finishers, 80%of non-finishers) experienced nausea and/or
vomiting. There were no statistically significant differences in
rate of food, fluid, or sodium intake between these cohorts,
suggesting that factors other than race diet contributed to the
onset of nausea and/or vomiting.
CONCLUSION
Completion of this 161-km trail race was associated with
greater fuel, fluid, and sodium consumption rates. In addition,
average intake rates were greater among finishers in the first
segment of the race. However, it should be noted that intake
ranges for fuel, fluid, and sodium consumption were large.
Some runners with relatively low intake rates finished, while
others with relatively high intake rates did not finish. Factors
beyond those examined in this study may have contributed to
successful completion of the race.
534 VOL. 30, NO. 6
Ultramarathon Race Diet
ACKNOWLEDGMENTS
The authors thank Ginger Hook, Dr. Kevin Fogard,
Benjamin Holexa, and Bill Butler for their crucial help in the
field. The study was supported by the Western States
Endurance Run Foundation.
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Received December 16, 2010; revision accepted July 18, 2011.
JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION 535
Ultramarathon Race Diet
