Effect of L-carnitine supplementation on the body carnitine pool, skeletal muscle energy metabolism and physical performance in male vegetarians.

PURPOSE: More than 95% of the body carnitine is located in skeletal muscle, where it is essential for energy metabolism. Vegetarians ingest less carnitine and carnitine precursors and have lower plasma carnitine concentrations than omnivores. Principle aims of the current study were to assess the plasma and skeletal muscle carnitine content and physical performance of male vegetarians and matched omnivores under basal conditions and after L-carnitine supplementation. RESULTS: Sixteen vegetarians and eight omnivores participated in this interventional study with oral supplementation of 2 g L-carnitine for 12 weeks. Before carnitine supplementation, vegetarians had a 10% lower plasma carnitine concentration, but maintained skeletal muscle carnitine stores compared to omnivores. Skeletal muscle phosphocreatine, ATP, glycogen and lactate contents were also not different from omnivores. Maximal oxygen uptake (VO2max) and workload (P max) per bodyweight (bicycle spiroergometry) were not significantly different between vegetarians and omnivores. Sub-maximal exercise (75% VO2max for 1 h) revealed no significant differences between vegetarians and omnivores (respiratory exchange ratio, blood lactate and muscle metabolites). Supplementation with L-carnitine significantly increased the total plasma carnitine concentration (24% in omnivores, 31% in vegetarians) and the muscle carnitine content in vegetarians (13%). Despite this increase, P max and VO2max as well as muscle phosphocreatine, lactate and glycogen were not significantly affected by carnitine administration. CONCLUSIONS: Vegetarians have lower plasma carnitine concentrations, but maintained muscle carnitine stores compared to omnivores. Oral L-carnitine supplementation normalizes the plasma carnitine stores and slightly increases the skeletal muscle carnitine content in vegetarians, but without affecting muscle function and energy metabolism.

Associations between trunk flexion and physical activity of patient care workers for a single shift: A pilot study.

BACKGROUND: Trunk flexion and occupational physical activity are parameters that have been used to assess and characterize jobs with high physical demands. OBJECTIVE: Characterize the physical load of trunk flexion and physical activity of patient care unit (PCU) workers during a single work shift. METHODS: Participants wore an accelerometer to measure physical activity and an inclinometer to assess trunk flexion during a single work shift, which was compared using correlation and linear regression analyses. RESULTS: Participants spent 74% of their work time upright between - 10° to 20° and 19% of their time flexed between 20° to 45°. On average workers spent 3% and 5% of their time, in the extreme postures of less than - 10° and greater than 45°, respectively. Participants spent 99% of their shift below moderate and vigorous activity. The largest correlation found was between the number of forward trunk flexions to 20° degrees per shift and minutes in lifestyle activity (r = 0.6, p < 0.001). No correlations between minutes of moderate or vigorous physical activity and trunk flexion were observed. CONCLUSIONS: This study suggests that the physical demands of patient care unit workers as measured through trunk flexion are associated with lifestyle and light levels of physical activity.

Physical activity at work contributes little to patient care workers' weekly totals.

OBJECTIVE: To determine the number of minutes of moderate and vigorous physical activity at work in comparison to weekly total minutes in a pilot study of 50 hospital patient care workers. METHODS: Workers wore accelerometers during work and nonwork hours for 7 days, and completed surveys at the end of the seventh day. RESULTS: Although the participants reported on average 206 minutes of moderate activity at work, the accelerometers recorded on average 30 minutes of moderate activity at work. For the 7 days the accelerometers measured a total of 165 minutes of moderate activity. Self-reported fatigue and functional limitations were negatively correlated albeit weakly with measured minutes of vigorous activity outside of work. CONCLUSIONS: Physical activity at work on patient care units contributes a small fraction to these workers' weekly totals, and in turn meeting guidelines.