Physiological Responses and Nutritional Intake during a 7-Day Treadmill Running World Record

Abstract

Ultra-running comprises running events longer than a marathon (>42.2 km). The prolonged duration of ultra-running leads to decrements in most or all physiological parameters and considerable energy expenditure (EE) and energy deficits. SG, 47 years, 162.5 cm, 49 kg, VO2max 4 mL/kg/min−1/2.37 L/min−1, ran continuously for 7 days on a treadmill in 3 h blocks followed by 30 min breaks and slept from 1–5 a.m. Heart rate (HR) oxygen uptake (VO2), rating of perceived exertion, weight, blood lactate (mmol·L−1), haemoglobin (g·dL), haematocrit (%) and glucose (mmol·L−1), and nutrition and hydration were recorded. SG ran for 17.5 h/day, covering ~120 km/day at ~7 km/h. Energy expenditure for each 24 h period was 6878 kcal/day and energy intake (EI) was 2701 kcal/day. EE was 382 kcal/h, with 66.6% from fat and 33.4% from carbohydrate oxidation. 7 day EI was 26,989 kcal and EE was 48,147 kcal, with a total energy deficit (ED) of 21,158 kcal. Average VO2 was 1.2 L·min−1/24.7 mL·kg·min−1, Respriatory echange ratio (RER) 0.80 ± 0.03, HR 120–125 b·min−1. Weight increased from 48.6 to 49.5 kg. Haemoglobin decreased from 13.7 to 11 g·dL and haematocrit decreased from 40% to 33%. SG ran 833.05 km. SG exhibits an enhanced fat metabolism through which she had a large daily ED. Her success can be attributed to a combination of physiological and psychological factors.

Fluctuations in Food and Fluid Intake During a 24-h World Championship: Analysis of the Deviation From Nutritional Programs

“…In a longer bike ultra-marathon (1,230 km; 54 h for 14 male participants), uid, CHO, and energy intake decreased during the second half of the race (13). Finally, Berger et al (18) reported decreases in energy and CHO intake after the rst day of a seven-day treadmill running world record attempt (833.05 km for 1 female participant). Overall, these studies (including the present one) support a hypothetical three-step model that clearly requires a stronger body of evidence: 1) a progressive increase or at least maintenance of CHO intake during the rst 12 h, 2) maintenance of all intake until 18-30 h of racing, and then 3) a decrease in all intake until the end of the race.…”

“…Fluctuations in food and uid intake during ultra-endurance races have only been poorly described (13,14,17,18), likely due to the di culty of accurately recording real-time intake. CHO intake was observed to increase during the second half of 100-km (12 h 49 min for 1 female participant) (14) and a 120-km ultramarathons (mean: 12 h 19 min for 5 male participants) (17).…”

“…The authors of the study of Geesman et al (13), which was based on anecdotal reports, attributed the decrease in intake during the second half of the race to 1) feelings of saturation induced by the ingestion of large amounts of food and drink, 2) feelings of sensoryspeci c satiety due to high amounts of CHO intake, and 3) the inability to maintain sustained frequent food and drink intake because of mental fatigue. Finally, in the study of Berger et al study (18), the authors indicated that the participant modi ed her diet on days 2 and 3 to privilege liquid CHO sources due to treadmill-induced motion sickness. With the exception of the aforementioned decrease in consumption opportunities, we did not observe any modi cations in intake in this race.…”

“…However, participants of this race minimized the quantity of food items to limit load carriage and were not offered alternative nutritional propositions, as in our study, making comparison with our study di cult. During the seven-day treadmill world record attempt (18), the authors mentioned that the participant was unable to respect her program (quantities that were too large to consume during her breaks and modi cation of her diet induced by motion sickness) but they only a rm that her "initial nutrition strategy would have matched her energy expenditure more closely", without publishing concrete data.…”

“…To date, the vast majority of studies to record food and uid intake have only considered total amounts rather than a real-time approach, an observation that can be easily explained by the obvious logistical di culties in recording all intake during long races, especially those involving a one-way route. However, when adopted, such a temporal approach has allowed the identi cation of uctuations in energy, macronutrient, and/or uid intake during ultra-endurance races (13,14,17,18). Moreover, such analysis may help in assessing the pertinence of designing and following a nutritional program by highlighting the periods of divergence between expected and actual intake and observing the potential effects of undesirable in-course events, such as the occurrence of GIS.…”