Energy availability describes the amount of dietary energy remaining for physiological functionality after the energy cost of exercise is deducted. The physiological and hormonal consequences of low energy availability (LEA) are well established, but the impact of LEA on physical activity behavior outside of exercise and, specifically, nonexercise activity thermogenesis (NEAT) has not been systematically examined. The authors conducted a secondary analysis of a repeated-measures crossover study in which recreationally trained young men (n = 6, 25 ± 1.0 years) underwent two 4-day conditions of LEA (15 kcal·kg fat-free mass−1 ·day−1) with and without endurance exercise (LEA + EX and LEA EX) and two energy-balanced control conditions (CON + EX and CON EX). The duration and intensity of physical activity outside of prescribed exercise were assessed using the SenseWear Pro3 armband. LEA did not alter NEAT (p = .41), nor time spent in moderate to vigorous (p = .20) and low-intensity physical activity (p = .17). However, time spent in low-intensity physical activity was lower in LEA + EX than LEA − EX (13.7 ± 0.3 vs. 15.2 ± 0.3 hr/day; p = .002). Short-term LEA does not seem to impact NEAT per se, but the way it is attained may impact physical activity behavior outside of exercise. As the participants expended similar amounts of energy during NEAT (900–1,300 kcal/day = 12.5–18.0 kcal·kg fat-free mass−1·day−1) and prescribed exercise bouts (15.0 kcal·kg fat-free mass−1·day−1), excluding it as a component of energy expenditure may skew the true energy available for physiological functionality in active populations.
Alexandra Martin, Hande Hofmann, Clemens Drenowatz, Birgit Wallmann-Sperlich, Billy Sperlich, and Karsten Koehler
Karsten Koehler, Thomas Abel, Birgit Wallmann-Sperlich, Annika Dreuscher, and Volker Anneken
Inactivity and overweight are major health concerns in children and adolescents with disabilities. Methods for the assessment of activity and energy expenditure may be affected negatively by the underlying disability, especially when motor function is impaired. The purpose of this study was to assess the validity of the SenseWear Armband in adolescents with cerebral palsy and hemiparesis.
Ten volunteers (age: 13.4 ± 1.6 years) were equipped with SenseWear Armbands on the hemiparetic and nonhemiparetic side of the body. Energy expenditure was measured at rest and during treadmill exercise (speed range: 0.85 to 2.35 m/s). Indirect calorimetry served as independent reference method.
The mean error was between −0.6 and 0.8 kcal/min and there were no significant differences between SenseWear and indirect calorimetry at any speed. Differences between body sides in expenditure (mean: −0.2 to 0.0 kcal/min) and step count (mean: −3.4 to 9.7 steps/min) were not significant.
The validity of the SenseWear Armband does not appear to be negatively affected by cerebral palsy during laboratory treadmill exercise. Future field studies are necessary to assess the validity and practicability of energy expenditure and physical activity assessment in children and adolescents with physical disabilities.