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

Nicolas Berger,Daniel Cooley,Russ Best,Michael Graham,Claire Harrison

doi:10.3390/ijerph17165962

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.

Highlights

Ultra-running comprises running events longer than a marathon (>42.2 km), with races contested over multiple distances (e.g., 50 km to 100 miles) or time periods (e.g., 24 h) in single-day and multi-day formats
We present data on a female multiple world record holding ultra-runner, examining haematological and physiological perturbations, as well as nutritional and recovery strategies, throughout a successful treadmill world record attempt for total distance completed in seven days on a treadmill (833.05 km)
Lactate threshold occurred at km·h−1, at a Heart rate (HR) of 157 b·min−1, corresponding to approximately 80% VO2max

Summary

Introduction

Ultra-running comprises running events longer than a marathon (>42.2 km), with races contested over multiple distances (e.g., 50 km to 100 miles) or time periods (e.g., 24 h) in single-day and multi-day formats. Examples of decrements in physiological parameters include a decrease in body mass and dehydration, loss of skeletal muscle mass, and increased total body water [6]. It is thought that an increase in body water could be the result of protein catabolism and the corresponding development of hypoproteinaemic oedema [7]. The resulting increase in plasma proteins and increase in plasma volume are suggested to be the result of increased plasma sodium concentration and increased activity of vasopressin. The retention of sodium is most likely due to increased activity of aldosterone [8,9,10]

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Conclusion