Poor Performance Status
Conditions
Brief summary
The purpose of this study is to investigate the influence of a nighttime feeding on next morning running performance, hydration status, and exercise metabolism in female endurance athletes. Specifically, the effect of a chocolate milk beverage will be examined versus a non-nutritive, flavor-matched placebo. The investigators hypothesize that the nighttime consumption of chocolate milk, a whole food complex, will result in improved next morning running performance versus placebo. Secondarily, the investigators hypothesize that any potential positive performance outcomes from the chocolate milk treatment may be due to an enhanced pre-exercise hydration status or improved exercise metabolism.
Detailed description
This study will be interventional in nature and employ a crossover, randomized, double-blinded approach. This study will include a maximal oxygen uptake test and three trials: one familiarization trial, and two experimental trials. The familiarization will serve as a practice test to minimize any training effects between experimental trials. The experimental trials will be completed within a 2-week period determined by the luteal phase of the menstrual cycle (days 15-28 of the menstrual cycle, with day 1 being the first day of menstruation). A minimum of 48-72 hours will be provided between testing days. Experimental trials will consist of baseline testing (height, weight, urinalysis, resting metabolic rate), followed by a treadmill performance protocol. Participants will complete a 3-stage incremental exercise test (at 55%, 65%, and 75% of maximal oxygen uptake respectively). Metabolic data will be collected during this time. Participants will then complete a 10-kilometer running time trial in which markers of intensity are monitored at various time points (blood glucose, blood lactate, heart rate, rating of perceived exertion). Participants and primary researchers will be blinded to all time and speed data. Distance will be the only known measure of progress. Additional blood, urine, and body weight measures will be taken immediately post exercise.
Interventions
OTHERchocolate milk
12 oz, 7-8 hours prior to exercise trial (night before)
OTHERflavor-matched placebo
12 oz, non-caloric flavor-matched placebo
Sponsors
Florida State University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
OTHER
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* Female * Between the ages of 18 and 40 years old * Consistently use oral contraceptives (greater than 2 months) or be considered eumenorrheic without oral contraceptive use * 'Moderately trained,' defined as a weekly mileage ≥ 25 miles for at least 6 months, and a VO2max ≥ 45 ml/kg/min
Exclusion criteria
* Lactose intolerant * Smokers * Uncontrolled thyroid conditions * Uses anti-inflammatory drugs or any dietary supplements intended to improve performance * Have musculoskeletal injury that could limit performance
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Running Performance | 24 hours | 10K time trial on a treadmill |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Urine Specific Gravity | 24 hours | Changes in urine specific gravity will be measured pre and post a 10K time trial run on a treadmill |
| Urine Volume | 24 hour | Measurement of total urine output. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Exercise Metabolism | 24 hours | Indirect calorimetry will be used to assess macronutrient use during exercise via the respiratory exchange ratio |
Countries
United States
Participant flow
Recruitment details
12 subjects were recruited from the Tallahassee running community.
Pre-assignment details
Subjects were randomized to receive either chocolate milk first or placebo first. In between exercise trials, there was a 7-day washout period.
Participants by arm
| Arm | Count |
|---|---|
| Chocolate Milk First, Then Placebo chocolate milk: 12 oz, 7-8 hours prior to exercise trial (night before) followed by a 7-day washout, then placebo 7-8 hours prior to exercise trial. | 6 |
| Flavor-matched Placebo, Then Chocolate Milk flavor-matched placebo: 12 oz, 7-8 hours prior to exercise trial (night before) followed by a 7-day washout, then chocolate milk 7-8 hours prior to exercise trial. | 6 |
| Total | 12 |
Baseline characteristics
| Characteristic | Flavor-matched Placebo, Then Chocolate Milk | Total | Chocolate Milk First, Then Placebo |
|---|---|---|---|
| Age, Continuous | 29.3 years STANDARD_DEVIATION 7.1 | 29.8 years STANDARD_DEVIATION 6.5 | 30.3 years STANDARD_DEVIATION 6.4 |
| Body fat (%) | 22.1 % STANDARD_DEVIATION 5 | 21.8 % STANDARD_DEVIATION 5.1 | 21.4 % STANDARD_DEVIATION 5.7 |
| Maximal oxygen consumption (ml/kg/min) | 53.8 ml/kg/min STANDARD_DEVIATION 4.5 | 52.8 ml/kg/min STANDARD_DEVIATION 4.2 | 51.8 ml/kg/min STANDARD_DEVIATION 4.1 |
| Region of Enrollment United States | 6 participants | 12 participants | 6 participants |
| Sex: Female, Male Female | 6 Participants | 12 Participants | 6 Participants |
| Sex: Female, Male Male | 0 Participants | 0 Participants | 0 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 4 / 12 | 0 / 12 |
| serious Total, serious adverse events | 0 / 12 | 0 / 12 |
Outcome results
Primary
Running Performance
10K time trial on a treadmill
Time frame: 24 hours
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Chocolate Milk | Running Performance | 52.8 minutes | Standard Deviation 8 |
| Flavor-matched Placebo | Running Performance | 52.8 minutes | Standard Deviation 8.4 |
Secondary
Urine Specific Gravity
Changes in urine specific gravity will be measured pre and post a 10K time trial run on a treadmill
Time frame: 24 hours
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Chocolate Milk | Urine Specific Gravity | -0.005 Urine specific gravity | Standard Deviation 0.008 |
| Flavor-matched Placebo | Urine Specific Gravity | -0.002 Urine specific gravity | Standard Deviation 0.009 |
Secondary
Urine Volume
Measurement of total urine output.
Time frame: 24 hour
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Chocolate Milk | Urine Volume | 718.07 mililiters | Standard Deviation 260.82 |
| Flavor-matched Placebo | Urine Volume | 874.82 mililiters | Standard Deviation 179.6 |
Other Pre-specified
Exercise Metabolism
Indirect calorimetry will be used to assess macronutrient use during exercise via the respiratory exchange ratio
Time frame: 24 hours
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Chocolate Milk | Exercise Metabolism | 55% VO2max | 0.84 Respiratory exchange ratio | Standard Deviation 0.04 |
| Chocolate Milk | Exercise Metabolism | 65% VO2max | 0.85 Respiratory exchange ratio | Standard Deviation 0.04 |
| Chocolate Milk | Exercise Metabolism | 75% VO2max | 0.87 Respiratory exchange ratio | Standard Deviation 0.03 |
| Flavor-matched Placebo | Exercise Metabolism | 55% VO2max | 0.82 Respiratory exchange ratio | Standard Deviation 0.04 |
| Flavor-matched Placebo | Exercise Metabolism | 65% VO2max | 0.83 Respiratory exchange ratio | Standard Deviation 0.03 |
| Flavor-matched Placebo | Exercise Metabolism | 75% VO2max | 0.85 Respiratory exchange ratio | Standard Deviation 0.03 |