These all-natural, totally legal performance enhancers will help you feel less tired and more pumped-up.

• A Hearty Bowl of Fortified Flakes
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  Women who were given iron supplements were more efficient and had a lower heart rate when performing a given exercise, found an analysis by researchers at the University of Melbourne. The effect was strongest in women who were iron-deficient or anemic, as well as in elite athletes.

  The workout hack: Make sure you’re getting 18 mg of iron per day (27 mg if you’re pregnant); many fortified cereals have 100 percent of the RDA, confirming that they are, indeed, the breakfast of champions. Note: Even though women — especially vegetarians or those with heavy periods — are more likely to be iron-deficient, an excess of the mineral can be toxic, so talk to your doctor before heavying up with supplements.

• A Warm Up That Starts With Your Retinas
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  You know that exposing yourself — especially your eyes — to light in the morning helps your brain feel more alert, but it can wake up your muscles, too. Research has found that exposure to light for 30 minutes before waking (and additional light upon getting out of bed) can increase oxygen flow to muscles, boosting physical as well as cognitive performance.

  The workout hack: A dawn-simulator clock like this one by Lumie wakes you up by gradually filling your room with light.

• A Fruity Drink to Help You Recover
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  Even if you were on fire at the CrossFit box today, your burning muscles will prevent you from doing much of anything tomorrow. Watermelon, beloved by athletes as a thirst- quencher, has also been shown to lessen post-exercise muscle soreness and thus spur recovery. Exercisers who drank the antioxidant-rich juice an hour before exercise reported less discomfort than those who had a control drink, an effect the researchers attributed to the amino acid L-citrulline.

  The workout hack: Drink a bottle of real watermelon juice (not flavored sugar water) or eat a few slices of the fruit before a hard workout.

• A Faster, Stronger, Tougher, Bendy-er Friend
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  Sweating with a pal can make any workout seem to go by more quickly, but if you choose the right friend, the effect can be even greater. A partner who you perceive to be better at that activity could help increase your workout time and intensity by as much as 200 percent, found Brandon Irwin, a Michigan State University researcher. He told the American Council on Exercise that “feeling inadequate may be a potential key to motivation in exercise.”

  The workout hack: If you can’t work out together in person, you can compete online using apps like Fitocracy, MapMyFitness, RunKeeper and Strava.

• A Pre-Workout Pepper-Upper
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  While inhaling the scent of peppermint has been shown to decrease anxiety and fatigue and improve focus, this bracing scent didn’t seem to have much of an effect on physical performance. But when researchers asked people to drink a solution of water peppered with a few drops of peppermint essential oil, they found that the exercisers didn’t fatigue as quickly during workouts. They also had a lower heart rate and systolic blood pressure. This is probably because the peppermint opened up their lungs and improved oxygen flow to the brain, the researchers posited in the Journal of the International Society of Sports Nutrition.

  The workout hack: On the way to the gym, pop a few candies made with real peppermint oil.