You've just had a tough workout, and you're on your way home sweating and exhausted. You stop in the gas station to grab a cold can of Red Bull or Monster Energy for that all-important pick-me-up. But before you go, is it safe to eat an orange?
The answer is yes, it's perfectly safe — in fact, eating an orange before your workout might even help boost energy levels. When you think of citrus fruits like oranges, lemons and grapefruits they're usually associated with being used as snacks or ingredients in recipes.
But new research shows that oranges and other citrus fruits can actually be useful for athletes looking to boost their energy levels even before they begin working out.
"We have long known that citrus fruits like oranges and grapefruits have restorative effects on tired muscles," says study author Dr. Darryl LePan, director of the Center for Exercise Science at Purdue University. "This new research suggests that these fruits may actually encourage muscle strength."
The findings are being published today (Jan. 30) in the online edition of the journal Physiology & Behavior . [Study co-author and Purdue Exercise Science Assistant Professor Tim Hewett is also a member of the scientific advisory board for Power Plate. The Power Plate is a vibrating platform used to provide muscle stimulation. The use of it in this study was not the focus.]
The researchers say that when you eat an orange before starting a workout, you are actually doing your metabolism a favour. Citrus fruits contain high amounts of compounds known as polyphenols, which have been shown to increase the antioxidant levels in the body — and this could help protect your body from cell damage that might otherwise occur during exercise.
"Research suggests that antioxidants work to protect against muscle damage and help muscles function more efficiently," LePan said. "So the increased antioxidants are likely helping to prevent muscle tissue breakdown and create more efficient muscle contractions.
"While there are no magic bullets, consuming antioxidants in the form of citrus fruits like oranges and grapefruit before working out may help to improve performance."
The researchers studied 11 college-age males who were not accustomed to weight training. The participants were divided into two groups. One group consumed half a fresh orange; the other received orange juice that consisted of about the same amount of polyphenols. Neither group was allowed to eat or drink anything else after their first meal that day until after their eight-hour study session was complete.
The participants were then asked to complete three sets of squats. After the first round, the researchers measured how much weight was being used and other measurements related to peak load, strength and other variables. These measurements were repeated after the researchers had the study participants sit back for seven hours without food or drink. The same squat tests were administered again, comparing results from before and after the wait period.
The researchers found that those who consumed an orange before their workout set more weight on their squat-testing machine than those who had drank orange juice. The study authors say this was surprising because there was no significant difference in terms of muscle efficiency, peak load or fatigue between the two groups before this test started.
They also found that muscle soreness was reduced by about 70 per cent among the orange-eaters compared to those who had had orange juice. In addition, the researchers found that the strength improvements after a workout were about double among those who had consumed an orange.
"The results support our claims that consuming fresh whole fruits in their natural state can improve muscle contractions and endurance in untrained individuals," LePan said. "The timing of when this effect occurs — ie, before working out versus after a workout — is still unknown."
The researchers are currently looking at how a combination of amino acids and polyphenols from citrus fruits might affect endurance performance. They plan to include a placebo group that will not consume an orange.
It appears that a single whole orange can make all the difference in your next workout. They are rich in vitamin C, which helps to boost your immune system and reduce muscle soreness after a workout. Plus, oranges are low in calories and high in fibre, a nutrient that can help you feel fuller faster when you're dining on them.
However, the study authors say it's important to remember that the results of this study were based on research conducted with very specific participants who were exercising for the first time under laboratory conditions. Further research will be needed before definitive statements can be made about these findings at a more general population level.