Timing of Energy Availability on Menstrual Cycle Function

Conditions

• Menstrual Irregularity

Eligibility Criteria

Sex

FEMALE

Age

18 Years - 40 Years

Healthy Volunteers

Accepted

Interventions

• Artificially Sweetened Carbohydrate Beverage — DIETARY_SUPPLEMENT
  Beverage containing 0.7 g carbohydrate/ kg body mass/ h as a 2:1 mixture of glucose and fructose and artificial sweetener
• Artificially Sweetened Beverage — DIETARY_SUPPLEMENT
  Beverage containing no carbohydrates or kilocalories and an artificial sweetener

Study Details

The primary aim of this clinical trial is to evaluate how fasted prolonged exercise may influence circulating reproductive hormones (i.e., estradiol, progesterone, luteinizing hormone) and menstrual cycle length when energy availability is maintained at or above 30 kcal/kg lean body mass/ day among women who regularly do running or cycling exercise. A secondary aim is to determine the effects of fasted prolonged exercise on serum leptin and cortisol. Participants will be asked to do the following over a \~3 month enrollment period: * attend a laboratory visit at the beginning of the study to have their resting metabolic rate, aerobic fitness, and body composition tested * monitor their menstrual cycle length, urine hormones, perceived stress levels, and diet for \~3 months * complete 3, 90-minute exercise sessions on a stationary bike or treadmill either fed (consuming a carbohydrate meal 1 h prior and 0.7 g carbohydrate/ kg body mass/ h during exercise) or fasted (consuming no meal prior and no carbohydrates during exercise) during month \~3 * saliva samples will be taken prior to and after 90-minute exercise sessions for quantification of leptin and cortisol

Key Dates

Start date

Aug 1, 2024

Status verified

Apr 2026

Primary completion

Aug 31, 2027

Completion

Aug 31, 2027

Study Design

Enrollment

64 participants (estimated)

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

BASIC_SCIENCE

Arms

• Experimental: Fed with Carbohydrates
  Participants will complete 3, 90-minute stationary cycle or treadmill exercise sessions 1 h after consuming a meal containing 1 g carbohydrate/ kg body weight. During exercise, they will consume an artificially sweetened beverage containing 0.7 g carbohydrate/ kg body mass/ h as a 2:1 mixture of glucose and fructose.
• Placebo Comparator: Fasted without Carbohydrates
  Participants will complete 3, 90-minute stationary cycle or treadmill exercise sessions following an overnight fast. During exercise, they will consume an artificially sweetened beverage containing no carbohydrates.

Primary Outcome Measure

Urinary estrone-3-glucuronide (E3G) [ Time Frame: 3 months ]

Central Contacts

• Marissa Baranauskas, PhD
  719-255-4475
  [email protected]

Locations (1)

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