Pre-Workout Supplement, Arrhythmias and Exercise Stress Test

NCT07853066 | Completed

• 2 other identifiers: 8.071.33892811525.4.0000.0068
• Study Type: interventional
• Target: 62
• Locations: 1 country
• Sites: 1

Brief Summary

Pre-workout supplements are widely used by physically active individuals to enhance exercise performance. These products typically contain stimulant substances such as caffeine, beta-alanine, arginine, and tyrosine, which act on the cardiovascular and central nervous systems. Although their ergogenic effects are well established, their safety profile - particularly regarding cardiac arrhythmias during exercise - has not been thoroughly investigated. This study aimed to evaluate whether the acute ingestion of a commercially available multi-ingredient pre-workout supplement (V-FORT® ULTRA, Vitafor, Brazil) could trigger cardiac arrhythmias during a treadmill exercise stress test in young, physically active adults. A randomized, double-blind, placebo-controlled crossover design was used. Participants underwent two exercise stress tests separated by 3 to 10 days: a familiarization test (Day 1) and an intervention test (Day 2), in which they received either the pre-workout supplement or a placebo beverage. Neither the participants nor the research team conducting the test were aware of the allocated intervention until after test completion.

Conditions

Supplementation During Endurance Performance

Keywords

Supplementation during endurance performance

Outcome Measures

Primary Outcomes (1)

• Occurrence of Cardiac Arrhythmias During the Exercise Stress Test

  Presence or absence of cardiac arrhythmias identified on continuous 12-lead ECG during the treadmill exercise stress test and the 6-minute post-exercise recovery phase, compared between the pre-workout supplement and placebo conditions.

  During the treadmill exercise stress test and throughout the 6-minute post-exercise recovery phase (approximately 30 to 60 minutes per session, on Day 2)

Secondary Outcomes (2)

• Haemodynamic Responses During the Exercise Stress Test

  At rest, during each stage of the treadmill exercise stress test, at peak effort, and during the 6-minute post-exercise recovery phase on Day 2

• Exercise Stress Test Duration

  Day 1 (familiarization test) and Day 2 (intervention test), separated by 3 to 10 days

Study Arms (2)

Pre-Workout Supplement

EXPERIMENTAL

Participants received a single dose of V-FORT® ULTRA (Vitafor, Brazil), a multi-ingredient pre-workout supplement containing 200 mg caffeine, 2,000 mg beta-alanine, 1,000 mg arginine, 600 mg tyrosine, 300 mg phenylalanine, 415 mg carnitine, 1.9 g carbohydrate, vitamins (C, E, B6, B12) and minerals (sodium, magnesium, zinc); 8 kcal per 8 g sachet. The beverage was consumed up to 3 hours before the treadmill exercise stress test.

Dietary Supplement: Dietary Supplement

Placebo

PLACEBO COMPARATOR

Participants received a single dose of Tang® powdered juice (placebo), containing 2.6 g carbohydrate, 2.4 g sugars, 22 mg sodium, 1.1 mg zinc, 23 mg vitamin C, and 2.5 mcg vitamin D, with no stimulant substances. The beverage was prepared to be visually and organoleptically indistinguishable from the active supplement and was consumed up to 3 hours before the treadmill exercise stress test.

Dietary Supplement: Placebo

Interventions

Dietary Supplement DIETARY_SUPPLEMENT

Single dose of containing 200 mg caffeine, 2,000 mg beta-alanine, 1,000 mg arginine, 600 mg tyrosine, 300 mg phenylalanine, 415 mg carnitine, 1.9 g carbohydrate, vitamins (C, E, B6, B12) and minerals (sodium, magnesium, zinc); 8 kcal per 8 g sachet. Consumed up to 3 hours before the treadmill exercise stress test.

Pre-Workout Supplement

Placebo DIETARY_SUPPLEMENT

Juice

Placebo

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Age 18 to 30 years Both sexes Physically active, defined as engaging in at least 150 minutes of moderate-intensity physical activity or 75 minutes of vigorous-intensity physical activity per week, assessed by the International Physical Activity Questionnaire (IPAQ) Prior experience with pre-workout supplements (at least one previous use of any stimulant-based pre-workout supplement) No cardiac arrhythmias identified during the familiarization exercise stress test (Day 1)

You may not qualify if:

• Presence of cardiac arrhythmias identified during the familiarization exercise stress test (Day 1) Physical inactivity (below the minimum physical activity thresholds on IPAQ) No prior use of any pre-workout or stimulant supplement Use of medications that may interfere with cardiovascular responses to exercise or supplementation Presence of known cardiovascular, metabolic, or musculoskeletal conditions that contraindicate exercise testing Orthopaedic limitations precluding treadmill exercise

Sponsors & Collaborators

• University of Sao Paulo: lead

Study Sites (1)

Pro-Coracao

São Paulo, São Paulo, 05021-010, Brazil

Location

MeSH Terms

Interventions

Dietary Supplements

Intervention Hierarchy (Ancestors)

Food; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: The study beverage (pre-workout supplement or placebo) was prepared by a study nurse who was not part of the research or outcomes assessment team. The nurse was the only individual aware of the allocation. Participants, the exercise testing team, and the outcomes assessors remained blinded until after complete test execution.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: PhD

Model Details: Each participant completed two treadmill exercise stress tests separated by 3 to 10 days. On Day 1, a familiarization test was performed to assess baseline cardiac rhythm and exclude participants with pre-existing arrhythmias. On Day 2, participants were randomized (1:1) to receive either the pre-workout supplement or placebo, consumed up to 3 hours before the second exercise stress test. Both tests were performed at the same time of day. The sequence of conditions was determined by randomization, and allocation was concealed from both participants and the testing team until after test completion.

Study Record Dates

• First Submitted: September 27, 2026
• First Posted: October 1, 2026
• Study Start: March 3, 2026
• Primary Completion: September 3, 2026
• Study Completion: September 3, 2026
• Last Updated: October 1, 2026

Record last verified: 2026-09

Locations

BR (1)