March, 2007
Speeding Recovery — Nutrition and Supplementation for Exercise
By Marie Spano, MS, RD, CISSN, and Chad M. Kerksick, PhD, CSCS*D, ATC, NSCA-CPT*D
Today’s Dietitian
Vol. 9 No. 3 P. 30

A serious workout can leave athletes sore and can even lead to muscle damage. Fortunately, certain nutrients and supplements can be key players in postexercise recovery.

That euphoric, revved-up feeling that follows a great workout can fade quickly, once fatigue and soreness set in. From the weekend warrior who throws in his shoes after a day of ultimate Frisbee to the seasoned, competitive athlete who cannot finish his second workout of the day, recovering from exercise isn’t always easy. Luckily, sports scientists are churning out research that may provide solutions to recovery, soreness, and inflammation.

If you are sore, you know you’ve had a good workout, right? Maybe. Continual and/or excessive soreness is not ideal and may be due to a lack of adequate recovery. The majority of soreness and damage results from muscle contractions when the muscle is forcibly lengthened, as in an eccentric contraction. For example, the eccentric portion of a bicep curl would be as the weight is being lowered or the elbow is straightening. These contractions are associated with increased levels of muscle soreness and various blood markers of muscle injury such as creatine kinase (CK) and lactate dehydrogenase (LDH). Secondary to the muscle damage, inflammation and oxidative stress also increase.

To better understand this process and investigate various nutritional, nutraceutical, and pharmaceutical interventions that may help prevent or offset muscle damage and ensuing soreness, researchers continually employ eccentric-only or “muscle damage” exercise bouts. While the magnitude of damage may be much greater in these studies, eccentric muscle contractions occur every time someone sprints down a field, throws a ball, jumps up and down, or lifts a weight, which is why these studies are of such great interest to those people interested in optimal recovery from exercise.

Nutritionally, total calories should be the first consideration to offset muscle soreness and promote recovery. Consuming adequate energy will not only help individuals reshape their physique, but it will also ensure they have enough energy to facilitate recovery from a tough exercise bout or demanding training program. From the most sedentary to the elite, athletes need energy to function; only the amount differs between individuals. Additionally, a limited supply of stored carbohydrate exists in our bodies, and as these levels become depleted, exercise performance decreases. However, no stored form of protein exists, so when a person’s diet isn’t providing enough carbohydrate to offset daily demands, existing protein will be broken down. Given that our muscle mass is the largest source of protein and amino acids, it is the first target. Dependence on either of these sources of fuel is not an ideal scenario, which makes a diet with an adequate amount of calories important. Exercising individuals should consume approximately 40 to 50 calories for every kilogram of body weight, with slight changes in either direction for those who may want to gain or lose weight, respectively.1 Adequate protein is vital, and a wealth of research indicates that an active individual should take in 1.2 to 1.5 grams of protein for every kilogram of body weight.2 This includes all athletes, not only those looking to put on mass.

Creatine
Creatine is one of the most popular, effective, and researched sports supplements. Hundreds of studies support creatine’s use to increase creatine phosphate levels as well as promote improvements in anaerobic power, work output, and maximal strength.3 Several hundred published studies demonstrate that creatine is effective at improving the cell’s ability to balance energy, while the evidence related to muscle damage and soreness is still limited. A randomized study published in 2004 supplemented athletes for five days with either creatine or a placebo prior to completing a 30-kilometer run. After seeing increases in various markers of cell damage and inflammation in the placebo group with no changes in the creatine group, the authors conclude that creatine may be an effective addition to help promote recovery and minimize muscle damage.4

Beta-alanine
Sports scientists have recently developed a growing interest in beta-alanine and its ability to delay fatigue and promote greater levels of work. Much like creatine, beta-alanine works within the muscle cell as part of a buffer cycle, which helps prevent fatigue. It does this by serving as the rate-limiting substance in carnosine production, which has antioxidant properties and works as a buffer to offset acid production in the muscle. One initial study provided 4 to 6 milligrams of beta-alanine every day for 10 weeks, resulting in increases in muscle carnosine by 50% and 80% after four and 10 weeks, respectively. An exhaustive cycling test was then completed that resulted in a 13% increase in total work after four weeks of supplementation and 3.2% after 10 weeks, with no changes in the placebo group.5

The next step researchers took was to combine beta-alanine and creatine. One of these studies supplemented males with 1.6 grams per day of beta-alanine plus 5.25 grams per day of creatine for four weeks before completing exhaustion tests on a cycle ergometer. The group supplemented with beta-alanine plus creatine increased maximal oxygen uptake, power output at metabolic thresholds, and the percentage of maximal oxygen consumption, which was maintained at the ventilation threshold (the point at which ventilation deviates from a steady linear increase and instead increases exponentially).6

An additional study in collegiate football players over 10 weeks compared beta-alanine plus creatine, creatine only, or placebo alone in adaptations to resistance training. Significantly greater improvements in strength, muscle mass, and percent body fat were noted in the beta-alanine plus creatine supplemented group in comparison with the creatine only and placebo groups.7 While intense training increases muscle levels of creatine and carnosine, supplementation, even over brief periods, can raise the levels even higher. It loads the muscle cell with buffers that allow for greater recovery, which keeps athletes coming back for more.

Branched-Chain Amino Acids (BCAAs) and Beta-hydroxy Beta-methylbutyrate (HMB)
While creatine and beta-alanine are used to improve cellular conditions, researchers have investigated other products for their ability to mediate muscle damage and facilitate rebuilding and recovery from intense exercise. Collectively, BCAAs (eg, isoleucine, leucine, and valine) have been heavily researched for their potential to mediate muscle damage and soreness. In addition to muscle damage, leucine is also being researched for its role in preventing muscle loss, which many argue is also part of the recovery process—especially from resistance training. In this regard, one of these studies used an endurance bout of exercise (two hours cycling ride at approximately 70% of VO2 max) while supplementing with either a placebo or 12 grams per day of the BCAAs. The researchers discovered that when supplementing with the BCAAs, peak levels of enzymes reflective of muscle damage (eg, LDH and CK) were delayed from two hours to five days for LDH and from four hours to five days posttest for CK, which led them to conclude that BCAA supplementation may help reduce muscle damage associated with endurance exercise.8

In much the same regard, two other studies used eccentric muscle contractions to invoke much higher levels of muscle damage while supplementing with HMB, a derivative of the amino acid leucine. The first study supplemented subjects with 3 grams of HMB for 14 days prior to the damage bout and found that soreness was reduced after 24 hours; CK levels were decreased after 24 hours; and force production and swelling were decreased, all of which are characteristics of muscle damage.9 Another study used a similar protocol and suggested a supplementation period of at least 14 days with BCAA or HMB is needed to impart positive alterations in the muscle damage response.10 These findings are important for those interested in muscle recovery and suggest that increasing the circulating levels of amino acids, specifically leucine and the BCAAs, may be effective at minimizing the symptoms associated with muscle damage.9,10

Omega-3 Fats
Increased omega-3 concentrations in the blood are associated with decreased levels of proinflammatory markers (interleukin-6 [IL-6], IL-1ra, tumor necrosis factor alpha [TNF-alpha], C-reactive protein [CRP]) and higher levels of anti-inflammatory markers (soluble IL-6r, IL-10, transforming growth factor-beta).11 However, few studies have examined omega-3 intake and modulation of exercise-induced inflammation. Clinical and epidemiological research has demonstrated the ability of omega-3 fatty acid intake to decrease inflammatory markers, increase blood flow by up to 36% during exercise, and decrease symptoms (morning stiffness, tender or swollen joints, and joint pain) of rheumatoid arthritis.12,13

Scientists at the University of Florida investigated the effects of a supplement containing a mix of 300 milligrams of tocopherols, 800 milligrams of flavonoids, and 300 milligrams of docosahexaenoate on exercise-induced markers of cell damage and the inflammatory mediators CRP and IL-6. In this randomized study, 40 healthy, untrained males (aged 18 to 35) received either the supplement or placebo for 14 days prior to completing an eccentric-only exercise bout. Significant increases in pain, CK, and LDH, as well as a decreased range of motion for three days, were found after the exercise with significant group differences in IL-6 and CRP, indicating there is a potential role for this combination of supplements in mitigating the inflammatory response associated with exercise.14

Another study found that supplementation with 3.6 grams per day of fish oil for six weeks had no effect on exercise-induced increases in leucocytes and CK compared with placebo.15 A similar study in 22 women found no differences in measures of inflammation (cortisol, CK, IL-6, TNF-alpha) after delayed onset muscle soreness caused by maximal isokinetic eccentric contractions.16 In addition to the health benefits attributed to fish oil consumption, these studies provide preliminary but mixed evidence that fish oil supplementation may be effective at offsetting the soreness and inflammation that results after intense, damaging exercise.

Vitamins C and E
Exercise can increase the production of free radicals, ultimately leading to oxidative stress. By damaging proteins inside and outside the cell, including the cell membrane, the membrane becomes damaged and dysfunctional.17 The body has antioxidant systems located throughout the body and upon exercising, the internal systems are improved—however, not enough to offset the free radical production during exercise.17 Consequently, this process is somewhat inevitable, but science has investigated the role in which various vitamins, minerals, and other proteins act as antioxidants.

Vitamin C, or ascorbic acid, is a water-soluble vitamin that works as an antioxidant by deactivating the free radicals that commonly navigate throughout the cell. While little research supports the notion that increases in vitamin C will improve performance, these studies have shown that increasing vitamin C levels decreases the production of various by-products reflective of free radical production and oxidative damage.18

Much like vitamin C, research on vitamin E does not support its ability to increase or improve performance, but it has repeatedly been shown to help minimize damage to the cell membranes from free radicals. Any strategy that can enhance the body’s ability to effectively mediate free radical production can potentially serve to assist with recovery from intense and damaging exercise.

Research has suggested that when combining vitamins C and E, their ability to offset the production of free radicals and prevent oxidative stress is even greater than when acting alone inside the cell. While vitamins C and E may do little to improve performance, their ability to help modulate free radical production and oxidative stress make them reasonable considerations for individuals who need to optimize their recovery from exercise.

Caffeine
In one double-blind, placebo-controlled, repeated-measures experiment, nine college-aged females were given 5 milligrams per kilogram bodyweight (equivalent to approximately 2 cups of coffee per person) of caffeine or placebo 24 and 48 hours following 64 eccentric actions of their dominant quadriceps induced by electrical stimulation. One hour postingestion, delayed onset muscular soreness (DOMS) was measured by visual analog scale, and force loss was estimated by maximal voluntary isometric contractions and submaximal voluntary eccentric contractions.

Caffeine reduced pain significantly during the maximal contractions and had a small effect on pain reduction during the submaximal contractions. Although the exact mechanism by which caffeine may work hasn’t been elucidated, the authors surmised that caffeine may reduce pain by blocking the adenosine released during inflammation. This study was limited by the small number of subjects participating. Look for future research to support the potential benefits of caffeine for the reduction of DOMS and the effect of caffeine on markers of inflammation.19

Nutrient Timing
The two-hour postexercise window is characterized by an increased rate of substrate incorporation into the cellular structure. In fact, the window immediately after exercise—30 minutes postexercise—shows the greatest increases.20,21 The literature shows that providing carbohydrate and protein in at least a 3:1 to 4:1 ratio favoring carbohydrate stimulates the greatest adaptations to promote muscle recovery and growth. Recent studies have also suggested this combination will help prevent markers in the blood that are reflective of muscle damage.22

Two very similar, well-conducted studies required young, healthy males to complete exercise exhaustion trials on a cycle ergometer followed by time to exhaustion trials at a standard workload before supplementing with isocaloric carbohydrate-protein beverages in a 4:1 ratio.22,23 Performance was not improved; however, circulating levels of CK and LDH were improved, suggesting that supplementing with carbohydrate and protein in a 4:1 ratio may help minimize muscle damage associated with exhaustive exercise in addition to promoting greater restoration of muscle recovery.23,24

Exercise does a world of good for both mind and body—until you overdo it and end up with your legs propped up with several ice bags covering sore spots. The first measure of prevention for soreness and inflammation should always be proper training and progression. Beyond that, nutrition can play a key role with adequate calorie, carbohydrate, and protein intake being the most important initial considerations. In addition, current clinical research has suggested that creatine, beta-alanine, BCAAs, HMB, and omega-3 fats may be helpful at minimizing the pain, inflammation, and damage that occur after intense exercise.

— Marie Spano, MS, RD, CISSN, is an exercise physiologist; vice president of the International Society of Sports Nutrition (ISSN); spokesperson for the Tea Council of the USA and the ISSN; and a freelance writer, consultant, and speaker in the nutrition, fitness, and health industries.

— Chad M. Kerksick, PhD, CSCS*D, ATC, NSCA-CPT*D, is an assistant professor of exercise physiology and director of the Applied Biochemistry and Molecular Physiology Lab at the University of Oklahoma.

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10. Paddon-Jones D, Keech A, Jenkins D. Short-term beta-hydroxy-beta-methylbutyrate supplementation does not reduce symptoms of eccentric muscle damage. Int J Sport Nutr Exerc Metab. 2001;11(4):442-450.

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14. Phillips T, Childs AC, Dreon DM, et al. A dietary supplement attenuates IL-6 and CRP after eccentric exercise in untrained males. Med Sci Sports Exerc. 2003;35(12):2032-2037.

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17. Childs A, Jacobs C, Kaminski T, et al. Supplementation with vitamin C and N-acetyl-cysteine increases oxidative stress in humans after an acute muscle injury induced by eccentric exercise. Free Radic Biol Med. 2001;31(6):745–753.

18. Bryant RJ, Ryder J, Martino P, et al. Effects of vitamin E and C supplementation either alone or in combination on exercise-induced lipid peroxidation in trained cyclists. J Strength Cond Res. 2003;17(4):792-800.

19. Maridakis V, O’Connor PJ, Dudley GA, et al. Caffeine attenuates delayed-onset muscle pain and force loss following eccentric exercise. J Pain. 2006.

20. Tipton KD, Rasmussen BB, Miller SL, et al. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. Am J Physiol Endocrinol Metab. 2001;281(2):E197-E206.

21. Borsheim E, Tipton KD, Wolf SE, et al. Essential amino acids and muscle protein recovery from resistance exercise. Am J Physiol Endocrinol Metab. 2002;283(4):E648-E657.

22. Ivy JL, Goforth HW Jr, Damon BM, et al. Early postexercise muscle glycogen recovery is enhanced with a carbohydrate-protein supplement. J Appl Physiol. 2002;93(4):1337-1344.

23. Romano-Ely BC, Todd MK, Saunders MJ, et al. Effect of an isocaloric carbohydrate-protein-antioxidant drink on cycling performance. Med Sci Sports Exerc. 2006;38(9):1608-1616.

24. Saunders MJ, Kane MD, Todd MK. Effects of a carbohydrate-protein beverage on cycling endurance and muscle damage. Med Sci Sports Exerc. 2004;6(7):1233-1238.