November 4, 2013
Don’t you love how great it feels to take a hike, hit the gym, do some yard work or otherwise move your muscles? And don’t you hate how sore your poor muscles feel the next day? Ah, if only there were a way to get a good workout without suffering the after-aches.There is, a new study suggests…and it’s not only simple and economical, it’s tasty, too. The secret weapon: Watermelon.
Though watermelon has a reputation for being mostly, well, water—plus natural sugar—it’s actually pretty nutritious. Watermelon is high in vitamins A and C…ounce for ounce, it contains more of the powerful antioxidant lycopene than the much touted tomato…and it is one of only a few foods that provides L-citrulline, an amino acid our kidneys use to make arginine, a powerful vasodilator that can improve blood flow.
Some studies suggest that L-citrulline boosts athletic performance by increasing the amount of oxygen brought to muscles during exercise, which is why L-citrulline supplements are marketed for athletes. The new study, however, suggests that there’s a better way than supplements to get your L-citrulline…and that soreness prevention rather than performance enhancement is the true benefit.
More Help for Sore Muscles
FROM LAB TO GYM
The first part of the study took place in the laboratory, with the purpose of determining L-citrulline’s bioavailability. Cells that mimicked the construction and function of the lining of human intestines were placed in petri dishes and exposed to one of three concoctions…
- Natural watermelon juice, made by liquefying watermelon pulp in a juicer (this is basically what winds up in your digestive tract after you eat watermelon).
- Watermelon juice that had been pasteurized by heating it to 175°F for 40 seconds (as commercially available bottled watermelon juice typically is to increase its shelf life).
- An L-citrulline supplement mixed with water.
The researchers then measured the amount of L-citrulline that was absorbed by the intestine-like cells. Findings: Natural watermelon juice had a significantly higher absorption rate (18.87%) than the pasteurized juice (13.19%) or the supplement (11.85%)—meaning that the unadulterated watermelon juice provided the most bioavailable form of L-citrulline.
The next part of the study took place in a gym. Participants included physically active young men who, over the course of two weeks, performed the same exercise routine three times. Each time, one hour before starting their workouts, they drank 17 ounces of either natural, unpasteurized watermelon juice (containing 1.17 grams of L-citrulline)…unpasteurized watermelon juice enriched with extra L-citrulline (for a total of 6.0 grams of L-citrulline)…or a placebo drink (an infusion of fruits and other plants that did not contain L-citrulline). All of the drinks looked alike and had the same natural sugar content. Participants were not told what the drinks contained or what effects the researchers were looking for.
The men wore heart rate monitors while riding stationary bikes at a very heavy resistance setting. They periodically rated their perceived exertion levels during the workouts…and reported their degree of muscle soreness 24 hours and 48 hours after completing the exercise routines. Each participant did the workout on three separate occasions so that everyone’s reaction to each drink could be measured.
Results: Participants reported significantly less muscle soreness 24 hours after drinking watermelon juice than after drinking the placebo concoction. (After 48 hours, soreness levels were minimal no matter which drink was consumed.) Interestingly, post-exercise soreness ratings were the same with the natural watermelon juice as with the enriched watermelon juice—suggesting that the unadulterated juice provided enough L-citrulline to reduce muscle soreness, and that the extra dose of L-citrulline in the enriched juice did not provide any additional benefit.
Surprisingly, given L-citrulline’s reputation as a performance enhancer, there were no differences in cycling speed, heart rate or perceived exertion no matter which drink the participants consumed before their workouts. However, it’s possible that consuming watermelon might enhance performance not on the same day, but rather on subsequent days, by making your muscles less sore and therefore allowing you to work out harder. It’s also possible that, if you consistently consume watermelon, then this performance boost might be ongoing. Further research would be needed to explore that theory…and also to determine how helpful watermelon juice might be for other types of people, such as women, for novice exercises or for elite athletes. These researchers hope to do additional studies on watermelon juice in the near future.
In the meantime, though, if you’re anticipating a strenuous workout, why not pull out your juicer and make some watermelon juice or just eat some watermelon before you exert yourself to see if this keeps your muscles from aching afterward? To get the same 1.17 grams of L-citrulline used in the study, you would need to drink 17 ounces of watermelon juice…or eat about four cups of cut-up watermelon cubes.
Source: Encarna Aguayo, PhD, associate professor, department of food engineering, Universidad Politécnica de Cartagena, Spain. Her study was published in Journal of Agricultural and Food Chemistry
http://www.bottomlinepublications.com/content/article/diet-a-exercise/watermelon-prevents-sore-muscles
