The purpose of this study was to determine if there is a difference between the way in which aerobically trained and untrained women metabolize fats and carbohydrates at rest in response to either a high-fat or high-carbohydrate meal. Subjects, 6 per group, were fed a high CHO meal (2068 kJ, 76% CHO. 23% fat, 5% protein) and a high fat meal (2093 kJ, 21% CHO, 72% fat, 8% protein) in counterbalanced order. Resting metabolic rate (RMR) was measured every half-hour for 5 hours. RMR was similar between groups. Training status had no overall effect on postprandial metabolic rate or total energy expenditure. The high fat meal resulted in no significant differences in RMR or respiratory exchange ratio (RER) between groups. However, after ingesting a high CHO meal, trained subjects had a peak in metabolism at minute 60, not evident in the untrained subjects. In addition, postprandial RER from minutes 120-300 were lower and fat use was greater after the high CHO meal for the trained subjects. These results suggest that aerobically trained women have an accelerated CHO uptake and overall lower CHO oxidation following the ingestion of a high CHO meal.
Victoria L. Bowden and Robert G. McMurray
William McGarvey, Richard Jones and Stewart Petersen
The purpose of this investigation was to examine the effect of interval (INT) and continuous (CON) cycle exercise on excess post-exercise oxygen consumption (EPOC). Twelve males first completed a graded exercise test for VO2max and then the two exercise challenges in random order on separate days approximately 1 wk apart. The INT challenge consisted of seven 2 min work intervals at 90% VO2max, each followed by 3 min of relief at 30% VO2max. The CON exercise consisted of 30 to 32 min of continuous cycling at 65% VO2max. Gas exchange and heart rate (HR) were measured for 30 min before, during, and for 2 h post-exercise. Three methods were used to analyze post-exercise oxygen consumption and all produced similar results. There were no significant differences in either the magnitude or duration of EPOC between the CON and INT protocols. HR, however, was higher (P < 0.05) while respiratory exchange ratio (RER) was lower (P < 0.05) following INT. These results indicate that when total work was similar, the magnitude and duration of EPOC were similar following CON or INT exercise. The differences in HR and RER during recovery suggest differential physiological responses to the exercise challenges.
Arthur H. Bossi, Wouter P. Timmerman and James G. Hopker
from the mean gas exchanges (L·min −1 ) in the last 3 minutes of each 7-minute bout according to Equation 1 . All participants fulfilled the criteria of a respiratory exchange ratio ≤1.0 in all trials. EE (J·s −1 ) was estimated assuming negligible protein oxidation, according to Péronnet and
Michael E. Hales and John D. Johnson II
), biceps femoris (BF), gastrocnemius medial head, and tibialis anterior (TA); and cardiopulmonary factors: maximal oxygen consumption (VO 2 max), heart rate (HR), respiratory exchange ratio (RER), metabolic equivalent of task (MET), and energy expenditure. The test course (20 × 20 m 2 area) consisted of 8
Sarah J. Willis, Jules Gellaerts, Benoît Mariani, Patrick Basset, Fabio Borrani and Grégoire P. Millet
calculated as the ratio between the difference between the V ˙ O 2 net and the baseline V ˙ O 2 and the treadmill speed (in m·min −1 ) and then multiplied by the energy equivalent of O 2 estimated by the respiratory exchange ratio. Heart rate was recorded continuously using a telemetry-based monitor
Mark Elisabeth Theodorus Willems, Mehmet Akif Şahin and Matthew David Cook
in men after 1- and 7-day intake with no intake on the day of testing. During 2 hr of cycling at 50% of maximum power, green tea extract had no effect on the respiratory exchange ratio ( Eichenberger et al., 2009 ). However, Venables et al. ( 2008 ) reported enhanced fat oxidation with green tea
Mark Glaister and Conor Gissane
ventilation ( V ˙ E ), 5 – 11 other studies have reported a significant increase. 12 , 13 Similarly, many studies reported no effect of caffeine on respiratory exchange ratio (RER), 6 , 8 , 9 , 11 , 13 – 23 though some studies have reported a significant decrease, 10 , 12 , 24 – 26 and one study, a
Pedro L. Valenzuela, Javier S. Morales, Adrián Castillo-García and Alejandro Lucia
oxidation—as reflected by lower values of plasma lactate and glucose concentration as well as of respiratory exchange ratio during exercise, together with higher intramuscular glycogen levels thereafter. 8 Thus, acute ketone supplementation could be an effective strategy for sparing muscle glycogen stores
Manuel D. Quinones and Peter W.R. Lemon
protocol. Expired breath-by-breath samples were collected for V ˙ O 2 and respiratory exchange ratio (RER; Vmax Legacy, SensorMedics) during the last 4 min of each exercise block. In addition, heart rate was monitored throughout (Cardio 660 ™ ; Sportline, Oakville, ON, Canada), and finger prick measures
Christopher Reiff, Kara Marlatt and Donald R. Dengel
Traditional desks require students to sit; however, recently schools have provided students with nontraditional standing desks. The purpose of this study was to investigate differences in caloric expenditure of young adults while sitting at a standard classroom desk and standing at a nontraditional standing classroom desk.
Twenty (10 male/10 female) young (22.8 ± 1.9 y), healthy participants reported to the laboratory between the hours of 7:00 AM and 2:00 PM following a 12-h fast and 48-h break in exercise. Participants were randomly assigned to perform a series of mathematical problems either sitting at a normal classroom desk or standing at a nontraditional standing desk. Inspired and expired gases were collected for 45-min for the determination of oxygen consumption (VO2), carbon dioxide production (VCO2), and minute ventilation (VE) using a metabolic gas system.
There were significant increases from sitting to standing in VO2 (0.22 ± 0.05 vs. 0.28 ± 0.05 L·min−1, P ≤ .0001), VCO2 (0.18 ± 0.05 vs. 0.24 ± 0.050 L·min−1, P ≤ .0001), VE (7.72 ± 0.67 vs. 9.41 ± 1.20 L·min−1, P ≤ .0001), and kilocalories expended per minute (1.36 ± 0.20 kcal/ min, P ≤ .0001 vs. 1.02 ± 0.22 kcal/min, P ≤ .0001).
Results indicate a significant increase in caloric expenditure in subjects that were standing at a standing classroom desk compared with sitting at a standard classroom desk.