Watermelon Juice for Heart Rate Recovery and Muscle Pain

Overseen By Mee Young Hong, PhD

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: San Diego State University

Must not be taking: Blood pressure medications

Disqualifiers: Injury, Chronic inflammation, Smoking, others

Compensation: Varies

Number of Visits: 2

Duration: 1 day

27 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how different drinks affect heart rate recovery, blood lactate levels (a marker for muscle fatigue), and muscle soreness after exercise. Participants will receive either watermelon juice (rich in citrulline), a sports drink, sugar water, or plain water before exercising. The goal is to determine which drink aids faster recovery and reduces muscle soreness the next day. The trial seeks healthy adults without injuries or chronic inflammation, who do not require certain medications or supplements, and are not allergic to watermelon. As an unphased trial, it offers participants the chance to contribute to new insights on exercise recovery and nutrition.

Do I have to stop taking my current medications for the trial?

The trial requires that you do not take any medication that affects blood pressure. If you are on such medication, you would need to stop taking it to participate.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research has shown that watermelon juice is generally safe to drink. The main ingredient, L-citrulline, has not been linked to any side effects. However, it may affect how some medications work, so consulting a doctor is important if taking any prescriptions. Studies have used watermelon juice to aid heart rate recovery and muscle soreness, and no safety issues have been identified. Overall, evidence suggests that most people tolerate watermelon juice well. ^{1 2 3 4 5}

Why are researchers excited about this trial's treatments?

Researchers are excited about watermelon juice as a treatment for heart rate recovery and muscle pain because it offers a natural alternative with unique benefits. Unlike typical sports drinks that rely heavily on artificial ingredients and sugars, watermelon juice is packed with natural antioxidants and amino acids like citrulline, which may enhance muscle recovery and reduce soreness. Additionally, its hydrating properties and naturally occurring sugars can potentially aid in faster heart rate recovery post-exercise. This makes watermelon juice a promising, holistic option for athletes and fitness enthusiasts seeking a more natural recovery solution.

What evidence suggests that this trial's treatments could be effective for heart rate recovery and muscle pain?

Research has shown that watermelon juice, one of the treatments under study in this trial, might aid heart recovery and reduce muscle soreness after exercise. Studies have found that drinking watermelon juice, which contains l-citrulline, can lessen muscle soreness 24 to 72 hours post-exercise. It also helps the heart return to its normal rate more quickly after physical activity. This effect likely occurs because l-citrulline improves blood flow by boosting nitric oxide levels in the body. Overall, these findings suggest that watermelon juice could benefit athletes or anyone seeking better recovery after physical activity. ^{1 6 7 8 9}

Are You a Good Fit for This Trial?

This trial is for healthy adults aged 21-50 who are not currently smoking, pregnant, allergic to watermelon, suffering from injuries or chronic inflammation. They should not be on blood pressure medications or dietary supplements.

Inclusion Criteria

We are looking for healthy adults between the ages of 21 and 50.

Exclusion Criteria

You have long-term inflammation in your body.

You smoke cigarettes.

You are allergic to watermelon.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

Treatment

Participants receive a single dose of watermelon juice, Gatorade, sugar water, or water before exercise

1 day

1 visit (in-person)

Follow-up

Participants are monitored for heart rate recovery and muscle soreness post-exercise

24 hours

1 visit (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• Sport drink
• Sugar water
• Water
• Watermelon juice

Trial Overview

The study tests the effects of a single dose of watermelon juice compared to Gatorade, sugar water, and plain water taken before exercise on heart rate recovery, blood lactate levels and muscle soreness after 24 hours.

How Is the Trial Designed?

Group I: Watermelon juice Experimental Treatment 1 Intervention

Group II: Sport drink Active Control 1 Intervention

Group III: Sugar water Active Control 1 Intervention

Group IV: Water Placebo Group 1 Intervention

Sport drink is already approved in United States, European Union, Canada for the following indications:

Approved in United States as Gatorade for:

• Replenishment of fluids and electrolytes during exercise
• Prevention of dehydration

Approved in European Union as Lucozade Sport for:

• Replenishment of fluids and electrolytes during exercise
• Prevention of dehydration

Approved in Canada as Powerade for:

• Replenishment of fluids and electrolytes during exercise
• Prevention of dehydration

Who Is Running the Clinical Trial?

San Diego State University

Lead Sponsor

Trials

182

Recruited

119,000+

Published Research Related to This Trial

A study involving 27 healthy adults found that consuming watermelon juice before exercise did not significantly improve heart rate recovery, blood lactate levels, or muscle soreness compared to other drinks.

However, watermelon juice was effective in preventing increases in blood pressure after exercise in females, suggesting a potential benefit for blood pressure control that may vary by sex.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of acute watermelon juice supplementation on post-submaximal exercise heart rate recovery, blood lactate, blood pressure, blood glucose and muscle soreness in healthy non-athletic men and women. Blohm, K., Beidler, J., Rosen, P., et al.[2021]

The developed isotonic beverage from natural apple concentrate effectively replenishes key electrolytes lost through sweat, such as sodium, potassium, and magnesium, making it suitable for athletes.

The beverage was optimized for taste and quality, achieving a shelf life of at least 3 months when stored at refrigeration temperatures, while providing 30% of the Recommended Daily Allowance of essential vitamins for physical activity.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Development and optimization of an isotonic sports drink]. López, L., Wittig de Penna, E., Bunger, A., et al.[2016]

Cherry juice is effective as a 'precovery' intervention, meaning it should be consumed several days before exercise to enhance muscle recovery, as shown in 15 studies measuring muscle function, soreness, and inflammation.

The timing of cherry juice consumption is crucial; starting the regimen before exercise leads to faster recovery, while starting on the day of or after exercise does not show beneficial effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

"Precovery" versus recovery: Understanding the role of cherry juice in exercise recovery. McHugh, MP.[2022]

Consuming 500 mL of Fashion watermelon juice enriched with l-citrulline significantly reduced muscle soreness perception from 24 to 72 hours after a half-marathon race, indicating its potential for recovery support.

Runners who consumed the watermelon juice showed lower plasma lactate levels and maintained jump height performance compared to those who had a placebo, suggesting enhanced exercise recovery and performance benefits.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Biochemical, physiological, and performance response of a functional watermelon juice enriched in L-citrulline during a half-marathon race. Martínez-Sánchez, A., Ramos-Campo, DJ., Fernández-Lobato, B., et al.[2022]

In a study involving 50 adult triathletes and runners, a commercially available 6% carbohydrate-electrolyte sports beverage (CCE) was found to be the most palatable and consumed the most during exercise compared to diluted orange juice (DOJ), homemade sports beverage (HCE), and water (W).

The results suggest that beverage palatability significantly influences voluntary intake during exercise, with CCE being preferred over other options, which could impact hydration and energy replenishment strategies for athletes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Palatability and voluntary intake of sports beverages, diluted orange juice, and water during exercise. Passe, DH., Horn, M., Stofan, J., et al.[2019]

The study identified xanthan gum as the best hydrocolloid for creating a sports energy gel from chia seeds, resulting in higher energy, viscosity, and potassium content compared to gels made with pectin or carboxymethyl cellulose.

The optimal chia seed gel formulation showed significant improvements in sensory characteristics, such as color and texture, which were positively received by taste panelists, indicating its potential for enhancing athletic performance and hydration during exercise.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Chia Seeds (Salvia hispanica L.): Can They Be Used as Ingredients in Making Sports Energy Gel? Lestari, YN., Farida, E., Amin, N., et al.[2021]

The study found that the hypotonic sports drink Mizone Rapid was absorbed faster than isotonic and hypertonic drinks, leading to a moderate decrease in serum osmolality and better gut comfort among cyclists.

Cyclists consuming Mizone Rapid achieved the highest peak power output compared to other drinks, suggesting potential performance benefits, although further research is needed to confirm the significance of these findings.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Unilateral fluid absorption and effects on peak power after ingestion of commercially available hypotonic, isotonic, and hypertonic sports drinks. Rowlands, DS., Bonetti, DL., Hopkins, WG.[2019]

Watermelon juice, especially when unpasteurized, enhances the bioavailability of l-citrulline, which is beneficial for reducing muscle soreness in athletes.

In a study with seven athletes, both natural and enriched watermelon juices significantly lowered recovery heart rates and muscle soreness after intense exercise, suggesting their effectiveness as functional drinks for athletic recovery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Watermelon juice: potential functional drink for sore muscle relief in athletes. Tarazona-Díaz, MP., Alacid, F., Carrasco, M., et al.[2013]

Coconut water, whether pure or from concentrate, is as effective as traditional carbohydrate-electrolyte sports drinks in promoting rehydration and supporting exercise performance after dehydration, based on a study with 12 exercise-trained men.

Participants reported feeling more bloated and experienced greater stomach upset after consuming coconut water compared to other beverages, indicating potential discomfort despite similar hydration outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparison of coconut water and a carbohydrate-electrolyte sport drink on measures of hydration and physical performance in exercise-trained men. Kalman, DS., Feldman, S., Krieger, DR., et al.[2021]

In a study involving 44 high school football players, a 7% glucose polymer beverage with electrolytes did not improve anaerobic performance after a scrimmage compared to a placebo, as both groups showed similar sprint velocities.

However, the glucose polymer beverage was more effective in maintaining plasma volume during recovery, indicating it may help with hydration better than the placebo after intense exercise.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Influence of a carbohydrate-electrolyte beverage on performance and blood homeostasis during recovery from football. Criswell, D., Powers, S., Lawler, J., et al.[2019]

A single dose of watermelon juice enriched with l-citrulline and pomegranate ellagitannins helped maintain muscle function and reduced muscle soreness after high-intensity exercise in a study of 19 healthy male subjects.

The combination of l-citrulline and ellagitannins showed a synergistic effect, leading to better performance and lower perceived exertion during exercise, suggesting potential benefits for recovery and exercise performance.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Consumption of Watermelon Juice Enriched in l-Citrulline and Pomegranate Ellagitannins Enhanced Metabolism during Physical Exercise. Martínez-Sánchez, A., Alacid, F., Rubio-Arias, JA., et al.[2019]

Watermelon juice supplementation significantly increased plasma levels of l-citrulline, l-arginine, and nitrite, which are associated with improved nitric oxide bioavailability, but it also raised resting blood pressure compared to control conditions.

Despite the benefits in muscle oxygenation during moderate-intensity exercise, watermelon juice did not enhance time-to-exhaustion during severe-intensity exercise, suggesting it may not be effective for improving endurance performance.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Two weeks of watermelon juice supplementation improves nitric oxide bioavailability but not endurance exercise performance in humans. Bailey, SJ., Blackwell, JR., Williams, E., et al.[2018]

In a study with seven trained cyclists exercising in heat for 120 minutes, rehydrating with commercial sports drinks (Gatorade and Powerade) significantly preserved leg power and force compared to not drinking anything (DEH), while water and a low-sodium drink did not provide the same benefits.

Cyclists who did not hydrate lost more body mass and had higher body temperatures, indicating that rehydration is crucial for maintaining performance in hot conditions, but the sodium content in sports drinks plays a key role in their effectiveness.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Anaerobic performance when rehydrating with water or commercially available sports drinks during prolonged exercise in the heat. Coso, JD., Estevez, E., Baquero, RA., et al.[2016]

To optimize recovery after endurance and team sports, athletes should consume about 1.2 g of carbohydrates per kilogram of body weight immediately after exercise and every hour for 4-6 hours, or 0.8 g of carbohydrates combined with 0.4 g of protein per hour.

Recovery beverages should also include electrolytes, particularly sodium, to aid rehydration, and recent studies suggest that chocolate milk may be as effective, or even superior, to commercial recovery drinks in promoting recovery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Building a beverage for recovery from endurance activity: a review. Spaccarotella, KJ., Andzel, WD.[2016]

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