l-Carnitinel-tartrate supplementation favorably affects markers of recovery from exercise stress

Abstract

nor. L-Carnitine L-tartrate supplementation favorably affects markers of recovery from exercise stress. Am J Physiol Endocrinol Metab 282: E474-E482, 2002; 10.1152/ajpendo. 00277.2001.-We examined the influence of L-carnitine L-tartrate (LCLT) on markers of purine catabolism, free radical formation, and muscle tissue disruption after squat exercise. With the use of a balanced, crossover design (1 wk washout), 10 resistance-trained men consumed a placebo or LCLT supplement (2 g L-carnitine/day) for 3 wk before obtaining blood samples on six consecutive days (D1 to D6). Blood was also sampled before and after a squat protocol (5 sets, 15-20 repetitions) on D2. Muscle tissue disruption at the midthigh was assessed using magnetic resonance imaging (MRI) before exercise and on D3 and D6. Exercise-induced increases in plasma markers of purine catabolism (hypoxanthine, xanthine oxidase, and serum uric acid) and circulating cytosolic proteins (myoglobin, fatty acid-binding protein, and creatine kinase) were significantly (P Յ 0.05) attenuated by LCLT. Exerciseinduced increases in plasma malondialdehyde returned to resting values sooner during LCLT compared with placebo. The amount of muscle disruption from MRI scans during LCLT was 41-45% of the placebo area. These data indicate that LCLT supplementation is effective in assisting recovery from high-repetition squat exercise. hypoxia; ergogenic aid; resistance exercise; muscle damage GIVEN THE OBLIGATORY ROLE of the carnitine system in transporting long-chain fatty acids to the mitochondrial matrix for oxidation (16), it is not surprising that there has been a great deal of research examining the potential of carnitine supplementation to enhance lipid oxidation, spare muscle glycogen, and improve exercise performance (3, 10). Despite the theoretical basis for usage of carnitine, the scientific literature has provided few "metabolic" benefits of carnitine supplementation for skeletal muscle during exercise, perhaps because of the difficulty of increasing carnitine concentrations in muscle with oral supplementation (2, 25). Using a different approach to study the effects of carnitine supplementation, Giamberardino et al. (7) demonstrated that eccentric exercise-induced delayed-onset muscle soreness and accumulation of creatine kinase during recovery was attenuated in subjects that supplemented with L-carnitine (3 g/day for 3 wk). Their findings indicate that carnitine supplementation may have a favorable effect on recovery from exercise. The study by Giamberardino et al., however, provided no data regarding potential mechanisms to explain the beneficial effect of carnitine supplementation.This study was designed to further examine the role of carnitine supplementation in acute exercise stress and its influence on biochemical events during recovery. Carnitine has been shown to stimulate fatty acid oxidation in vascular endothelial cells (14). Ischemia in endothelial cells results in release of carnitine, increased oxidative stress, and compromised blood flow regulation, wh...

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“…Lipid peroxidation results in the formation of numerous aldehydes of different chain lengths, such as the 3-carbon product malondialdehyde (MDA), which has been shown to increase with dynamic resistance exercise (Volek et al, 2002). In the current study, the MDA levels of BBE supplementation groups were significantly lower than that of the control group.…”

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“…In addition, phosphatidylserine has been shown to enhance subjective feelings of energy, elation and confidence in healthy students subjected to stressful mental tasks [30] and in combination with carbohydrates to improve performance in golfers during induced stress [31]. Carnitine supplementation has been shown to enhance recovery following high intensity exercise [32,33], as reflected by reduced markers of muscle damage and a greater anabolic response (elevation in IGF binding protein) to exercise recovery. Although the vitamins included in CRAM are not known to be ergogenic when no deficiencies are present, the energy matrix found in this supplement has been shown to be effective in delaying time to fatigue and increasing volume of training [34].…”

Nutritional Interventions as Potential Strategy to Minimize Exercise-Induced Muscle Injuries in Sports

“…These studies demonstrated that supplemental carnitine is effective in attenuating tissue damage as directly assessed via magnetic resonance imaging, muscle soreness, and postexercise markers of metabolic stress following eccentric exercise training [102] or intense resistance exercise [103][104][105] thus leading to a quicker recovery (2 to 3 g/day of elemental carnitine being supplied by L-carnitine L-tartrate, LCLT). In particular Volek and colleagues [103] analyzed the effects of L-carnitine (2g/d for 3 wk before exercise and during 4d recovery) on markers of muscle damage in trained adult man following 5 sets of 15-20 repetitions of squats at 50% of 1-RM. Treated subjects experienced reduced muscle damage and decreased circulating CK compared to placebo.…”

“…Furthermore ROS generated beyond physiological limits are found to reduce muscle force production by altering calcium ion sensitivity in muscle and thus contributing to muscle fatigue [107] [108,109]. Lcarnitine supplementation has been related to reduced postexercise CK [102,103] and myoglobin [103,105] concentrations suggesting that reduced oxidative stress may play a role in a quicker muscle recovery from strenuous exercise following supplementation. As a matter of fact early studies by Brass et al (1993) [110] demonstrated that L-carnitine delays hypoxiainduced fatigue in electrically stimulated rat skeletal muscle in vitro through its key stimulatory role in muscle bioenergetics and antioxidant activity.…”

“…This process is a direct consequence of raised intracellular calcium by inhibition of calcium ATPase pumps induced by insufficient supply of ATP. This response appears to be attenuated by L-carnitine supplementation which reduces intracellular hypoxanthine and xanthine oxidase following resistance exercise bouts [103,106]. Indeed inhibition of xanthine oxidase with allopurinol during exercise has been shown to result in significantly less generation of ROS, reduced tissue damage after exhaustive exercise [112], and less accumulation of cytosolic enzymes CK and LDH [113,114].…”