Effects of caffeine on exercise performance during different phases of the menstrual cycle in women practicing cross training

Acute effects of caffeine supplementation on anaerobic performance, heart rate variability, biochemical and psychobiological parameters, and muscle oxygenation across the menstrual cycle in women practicing cross training

Status

Recruiting

Phases

Unknown

Study type

Interventional

Source

REBEC

Registry ID

RBR-93tpczm

Enrollment

Registered

2026-07-16

Start date

2026-09-16

Completion date

Unknown

Last updated

2026-08-03

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Women

Interventions

This is a randomized, double-blind, placebo-controlled crossover trial involving 20 women aged 18 to 40 years who regularly practice cross training. Participants will be randomly assigned through a ra

Eligibility

Sex/Gender

Female

Age

18 Years to 45 Years

Inclusion criteria

Inclusion criteria: Women aged 18 to 40 years; Practicing cross training for at least 12 months; Minimum frequency of four training sessions per week; Regular menstrual cycle (eumenorrheic); Voluntary participation, with full understanding of the procedures and signing of the informed consent form (ICF)

Exclusion criteria

Exclusion criteria: Contraindications to caffeine consumption; history of cardiac arrhythmias; hypertension; gastrointestinal disorders; or psychiatric disorders; use medications or supplements that may interfere with caffeine metabolism; hormonal contraceptives; sedatives; anxiolytics; or thermogenic supplements; pregnant; breastfeeding; undergoing exogenous hormone therapy; irregular menstrual cycles; habitual consumers of high doses of caffeine; abstainers from caffeine; smokers; or frequent alcohol users; have non-rehabilitated injuries; uncontrolled metabolic or endocrine diseases; fail to comply with the experimental or dietary protocols of the study; present any condition that may limit the safe performance of the physical tests

Design outcomes

Primary

Measure	Time frame
Expected to observe an increase in absolute mean power, expressed in watts, and relative mean power, expressed in watts per kilogram of body mass, during anaerobic performance following acute caffeine supplementation, assessed using the Wingate test performed during the early follicular and luteal phases of the menstrual cycle, with data collected after administration of the intervention in each experimental session	—

Measure

Time frame

Expected to observe an increase in absolute mean power, expressed in watts, and relative mean power, expressed in watts per kilogram of body mass, during anaerobic performance following acute caffeine supplementation, assessed using the Wingate test performed during the early follicular and luteal phases of the menstrual cycle, with data collected after administration of the intervention in each experimental session

—

Secondary

Measure	Time frame
Expected to observe differences in blood concentrations of lactate, caffeine, and other biochemical parameters related to the physiological response to exercise between the experimental conditions, assessed through analyses of blood samples collected before and after each experimental session performed during the early follicular and luteal phases of the menstrual cycle;Expected secondary outcome: Expected to observe increased muscle oxygenation during exercise and throughout the recovery period, assessed using near-infrared spectroscopy, with data collected throughout the experimental protocol and during recovery in each session performed during the early follicular and luteal phases of the menstrual cycle;Expected to observe improvements in psychobiological parameters, including mood state, rating of perceived exertion, and alertness, assessed using validated instruments before administration of the intervention, during the experimental protocol, and at the end of each experimental session performed during the early follicular and luteal phases of the menstrual cycle;Expected to observe changes in heart rate variability in response to acute caffeine supplementation and physical exercise, assessed before administration of the intervention and immediately after the end of each experimental session performed during the early follicular and luteal phases of the menstrual cycle	—

Measure

Time frame

Expected to observe differences in blood concentrations of lactate, caffeine, and other biochemical parameters related to the physiological response to exercise between the experimental conditions, assessed through analyses of blood samples collected before and after each experimental session performed during the early follicular and luteal phases of the menstrual cycle;Expected secondary outcome: Expected to observe increased muscle oxygenation during exercise and throughout the recovery period, assessed using near-infrared spectroscopy, with data collected throughout the experimental protocol and during recovery in each session performed during the early follicular and luteal phases of the menstrual cycle;Expected to observe improvements in psychobiological parameters, including mood state, rating of perceived exertion, and alertness, assessed using validated instruments before administration of the intervention, during the experimental protocol, and at the end of each experimental session performed during the early follicular and luteal phases of the menstrual cycle;Expected to observe changes in heart rate variability in response to acute caffeine supplementation and physical exercise, assessed before administration of the intervention and immediately after the end of each experimental session performed during the early follicular and luteal phases of the menstrual cycle

—

Countries

Contacts

Public ContactAnderson Morales

Universidade Federal do Rio de Janeiro (UFRJ-Campus Macaé)

andersonmrl@hotmail.com+55(21)997087600

Outcome results

None listed

Source: REBEC (via WHO ICTRP) · Data processed: Aug 10, 2026