L-Carnitine improves physical performance

A new randomised, double blinded study shows that the nutrient L-Carnitine improves exercise performance. The researchers from the School of Biomedical Sciences at the University of Nottingham Medical School had 14 healthy male volunteers with an average age of 25.9 years and Body Mass Index of 23 perform an exercise test comprising 30 minute cycling at 50% VO2max (50% of their maximum performance), 30 minutes at 80% VO2max, then a 30 minute work output performance trial for peak activity. They did this on three visits separated by 12 weeks. After each visit the 14 men consumed either 80g of carbohydrate (CHO) or 2g of L-Carnitine and 80g of CHO twice daily for 24 weeks.

After that muscle total Carnitine increased by 21% in the L-Carnitine group and was unchanged in the control group. At 50%˙VO2max, the Carnitine group utilised 55% less muscle glycogen (the sugar stored in the muscle) compared to control (those not on L-Carnitine) compared to before supplementation. At 80% VO2max, muscle lactate content was 44% lower; the muscle was not becoming as acidified (acidifying the muscle leads to muscle seizing, cramping and soreness). The Carnitine group increased work output 11% from baseline in the performance trial. The study is published in the Journal of Physiology.