Effects of Herbal Supplements on Endurance Exercise Performance

Not Applicable

Completed

• Conditions: Exercise Performance
• Interventions: Dietary Supplement: Placebo of calcium; Dietary Supplement: Rhodiola and Cordyceps; Dietary Supplement: Rhodiola

• Registration Number: NCT03929575
• Lead Sponsor: California Polytechnic State University-San Luis Obispo

Brief Summary

Cordyceps and Rhodiola are two common herbal supplements marketed and consumed as adaptogens to athletes with regard to enhanced performance. The effects of these supplements has been well studied in animals but whether or not the same effects translate to humans is still unclear. Thus, the primary purpose of this study is to determine whether combined supplementation of Rhodiola and Cordyceps, compared to Rhodiola alone and placebo, will demonstrate a greater improvement in oxygen consumption (ie. VO2 max).

Detailed Description

Herbal supplements are consumed worldwide with surveys approximating five billion dollars spent annually by consumers in the United States alone. Herbal supplements, such as Rhodiola and Cordyceps, both of which are considered to be adaptogens, remain popular among athletes. These adaptogens act as antioxidants, which have been speculated to confer endurance performance benefits by delaying muscle fatigue via the attenuation of muscle damage accumulation and its related by-products during prolonged or exhaustive exercise. Nevertheless, previous research investigating the individual effects of Rhodiola and Cordyceps on aerobic training performance remain equivocal. Moreover, literature elucidating the potential additive effects of Rhodiola and Cordyceps in human subjects are scarce. Therefore, the purpose of the present study is to determine the acute, additive influence of oral Rhodiola and Cordyceps supplementation on VO2 max, with secondary variables of interest being plasma glucose and lactate concentration, and measures of gastrointestinal distress.

Study Timeline

• Study First Submitted: 2019-04-24
• Study First Submitted QC: 2019-04-25
• Study First Posted: 2019-04-29
• Study Start: 2019-05-01
• Primary Completion: 2019-12-01
• Study Completion: 2019-12-01
• Status Verified: 2021-01
• Last Update Submitted: 2021-01-25
• Last Update Posted: 2021-01-27

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 13

Inclusion Criteria

• Body Mass Index between 18.5 and 35 kg/m^2
• Non-smoking (assessed by Health History Questionnaire)
• English-speaking
• Regular participation in physical activity (>4 hours per week)

Exclusion Criteria

• Medical conditions that prohibit physical activity (assessed by Health History Questionnaire)
• Pregnant women or women expecting/trying to become pregnant
• BMI greater than or equal to 35 kg/m^2
• Current smoker (assessed by Health History Questionnaire)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Placebo of calcium	Placebo of calcium	Participants will consume 250 mg of calcium
Rhodiola and Cordyceps	Rhodiola and Cordyceps	Participants will consume a combination of 250 mg of Rhodiola and 225 mg of Cordyceps
Rhodiola	Rhodiola	Participants will consume 250 mg of Rhodiola

Primary Outcome Measures

Name	Time	Method
VO2 max	90 minutes after baseline	Maximum oxygen consumption using the Bruce Protocol

Secondary Outcome Measures

Name	Time	Method
Gastrointestinal symptoms questionnaire	Baseline, 90 minutes, 110 minutes	Section 1 contains 6 questions assessing upper abdominal problems (reflux, heartburn, bloating, cramps, vomiting, and nausea). Section 2 contains 7 questions assessing lower abdominal problems (intestinal cramps, flatulence, urge to defecate, left abdominal pain, right abdominal pain, loose stool, and diarrhea). Section 3 contains 4 questions assessing systematic problems (dizziness, headache, muscle cramp, and urge to urinate). Each of the 17 questions is answered using a 10-point scale ranging from 0 (no problem at all) to 10 (the worst it has ever been). Each of the 3 sections will be scored separately. Section 1 will be scored on a scale of 0-60. Section 2 will be scored on a scale of 0-70. Section 3 will be scored on a scale of 0-40.
Blood glucose	Baseline, 90 minutes, 110 minutes	Plasma glucose assessed by finger stick
Blood lactate	Baseline, 90 minutes, 110 minutes	Plasma lactate assessed by finger stick

Trial Locations

Locations (1)

California Polytechnic State University; 🇺🇸 San Luis Obispo, California, United States