The primary objective is to assess the impact of two nutritional interventions vs. placebo on objective and subjective sleep measures in athletes. Participants receive one beverage on each of three consecutive nights in a randomized manner. It is hypothesized the two nutritional interventions will result in significant improvements in sleep onset latency, and will not result in a negative impact on next-day cycling performance. The secondary objective is to assess the impact of the nutritional interventions vs. placebo on next-morning performance (physical, cognitive function, and balance).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
QUADRUPLE
Enrollment
19
250 ml beverage consumed at 21:00 hours
250 ml beverage consumed at 21:00 hours, matched in appearance and taste to the active beverages
Appleton Institute CQUniversity, School of Medical, Health, and Applied Sciences, Adelaide Campus
Wayville, South Australia, Australia
Total Sleep Time (TST)
Measured in minutes during polysomnography. Longer is better.
Time frame: Time from sleep onset to 8:00 a.m.
Wake After Sleep Onset (WASO)
Occurrences measured in minutes during polysomnography. None or less are better.
Time frame: From sleep onset till 8:00 a.m.
Sleep Efficiency (SE)
Measured as a % of time asleep over time in bed during polysomnography. Higher efficiency is better
Time frame: From sleep onset to 8:00 a.m.
Sleep Onset Latency (SOL)
Measured in minutes during polysomnography. Shorter time to onset is better.
Time frame: Transition from wakefulness to sleep
Rapid Eye Movement (REM) Latency
Measured in minutes during polysomnography. Shorter time to REM is better.
Time frame: From sleep onset to REM sleep
Sleep stage 3 Latency
Measured in minutes during polysomnography. Shorter time to stage 3 deep sleep is better.
Time frame: From sleep onset to deep sleep
Sleep stage 1, 2, 3 AND REM
Measured in minutes during polysomnography. Normal stage pattern is better.
Time frame: Measured continuously throughout the night from sleep onset to 8 a.m.
Arousals
Measured as a count during polysomnography. Less arousals are better.
Time frame: From sleep onset to 8 a.m.
Awakenings
Measured as a count during polysomnography. Less awakenings are better.
Time frame: From sleep onset to 8 a.m.
Stage shifts
Measured as a count during polysomnography. Normal amount of stage shifts are better.
Time frame: From sleep onset to 8 a.m.
Subjective Karolinska Sleepiness Scale (KSS)
Subjective arousal level at present state rated 1 (extremely alert) to 9 (Very sleepy, great effort to keep awake). Sleepiness before bed is better.
Time frame: Every thirty minutes from 20:00 p.m. until 22:30 p.m.
(Subjective) Perceived Sleep Quality
Rated from 1 (very good) to 5 (poor). Lower number is better.
Time frame: 08:30 a.m. following polysomnography
(Subjective) Sleep Quantity
Measured in hours and minutes. Higher number is better.
Time frame: 08:30 a.m. following polysomnography
(Subjective) Sleep Onset Latency
Measured in hours and minutes. Lower number is better.
Time frame: 08:30 a.m. following polysomnography
Exercise performance: power output
Cycle ergometer to measure power output in watts, with instructions to give maximal effort. Higher watts are better.
Time frame: During a 10 minute time trial cycling exercise performance testing at 9:30 a.m.
Exercise performance: perceived exertion
Rating of perceived exertion (RPE) on a scale of 6 (lower) to 20 (higher) intensity levels.
Time frame: During a 10 minute time trial cycling exercise performance testing at 9:30 a.m.
Exercise performance: heart rate
Measured in beats per minute (bpm) by heart rate monitor
Time frame: During a 10 minute time trial cycling exercise performance testing at 9:30 a.m.
Cognitive performance: sustained attention
Psychomotor vigilance reaction time task (PVT-192) handheld ambulatory monitoring
Time frame: 10 minute testing period at 9 a.m. Higher performance is better.
Subjective alertness
Rated on visual analog scale from 0 (feeling not at all alert) to 100 (feeling completely alert). Feeling more alert is better.
Time frame: 9 a.m. before cognitive performance attention testing.
Subjective self-perceived capacity to be fast on cognitive test
Rated on visual analog scale from 0 (expecting to not respond fast at all) to 100 (expecting to respond very fast). Better or worse not applicable.
Time frame: 9 a.m. before cognitive performance attention testing
Subjective self-perceived capacity to be accurate on cognitive test
Rated on visual analog scale from 0 (expecting to not respond accurately at all) to 100 (expecting to respond very accurately). Better or worse not applicable.
Time frame: 9 a.m. before cognitive performance attention testing
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Balance
Postural sway area 95cm/2 measured by computerized force platform. Less sway is better.
Time frame: 9 a.m. before cognitive performance attention testing.