Sleep and Human Performance Kevin Walker MD Scott Schauss PA-C Intermountain Sleep Disorders Clinic
Disclosures:
Objectives How sleep extension and restriction impact performance To Nap or Not to Nap Circadian Shifts impacts on athletic performance. Real world examples
Sleep Extension
Study Objectives: Investigate the effects of sleep extension over multiple weeks on specific measures: Athletic performance Reaction Time Mood Daytime Sleepiness Mah et al; SLEEP 2011; 34(7):943-950
Maintain habitual sleep-wake schedule for a 2-4 week baseline during the regular season, including naps 6-9h subjective sleep 5-7 week sleep extension As much extra sleep possible Minimum goal of 10h in bed per night - No caffeine or ETOH - Sleep alone - When travelling, share a bedroom but sleep in separate beds
Three point: Baseline: 10.2 SE: 11.6 P<0.001 282ft sprint: Baseline- 16.2 sec SE:15.5 sec P<0.001 Free Throws: Baseline: 7.9 SE:8.8 P<0.001
15m sprint: 0.51sec Start times: 0.15sec
Sleep deprivation overview Sleep Deprivation must be greater than 30h (up all night remaining awake through the afternoon) to have an impact on anaerobic performance- Skein et al., 2011 Mean and total sprint times decreased significantly following 30hr SD- Skein et al., 2011 Aerobic performance may be decreased after only 24h SD- Oliver et al., 2009
Partial sleep deprivation overview 2.5hr of sleep per night x 4 nights in swimmers showed significant alterations on mood with increases in depression, tension, confusion, fatigue, anger and decreases in vigor. No effect on back/grip strength, lung function, or swimming performance. -Sinnerton et al.,1992 Significant effect on maximal bench press, leg press, and dead lifts but not maximal bicep curl after two nights of partial sleep deprivation (3hrs TST). All four tasks were significantly affected on sub-maximal performance. Reilly et al., 1994 Overall sub-maximal prolonged tasks may be more affected than maximal efforts, particularly after the first two nights of partial sleep deprivation. Reilly et al., 1994
Napping
Napping One way to counter sleep reduction and daytime sleepiness What duration is optimal? Even short naps (7.3-20 minutes) help improve alertness and performance after restricted and normal nocturnal sleep (Gillberg 1996; Horne 1996; Takahashi 1998, 2000; Tietzel 2001, 2002; Hayashi 1999, 2003, 2005) Effects on alertness after 7.3 and 30 minute nap can last up to 3 hours in the setting of normal nocturnal sleep (Takahashi 1998) 10 vs 30 minute naps have same effects an hour afterward in the setting of mild sleep restriction (Tietzel 2001) Longer 1-2 hour naps are more alerting than short naps in the setting of total sleep deprivation (Helmus 1997, Lumley 1986) Practical disadvantage Greater sleep inertia (most achieve stage N3 sleep during 30-minute nap) Impact on subsequent nocturnal sleep
A Brief Afternoon Nap Following Nocturnal Sleep Restriction: Which Nap Duration is Most Recuperative? Brooks A, Lack L. SLEEP 2006;29(6):831-840 24 good-sleeping students 1 week of regular bed times followed by a night of a restricted 5 hours of sleep Sleep logs and activity monitors showed mean reduction of ~2.5 hours of sleep No alcohol or caffeine for 3 days prior to laboratory sessions, normal lunch within hour of nap, no vigorous mental or physical activity for 30 minutes prior to sessions No-nap, 5-, 10-, 20-, and 30-minute naps ending at 3:00 pm Stanford Sleepiness Scale, fatigue and vigor subscales of the Profile of Mood States, Symbol-Digit Substitution Task, Letter Cancellation Task, simple visual reaction time task Postnap sleep latency trials at 65, 125, 185 minutes after nap 20 minute periods, awakened after 3 epochs of sleep
Measures of alertness and performance SSS Fatigue Vigor SDST LCT Median RT RT Lapses 5-minute 35-95 min 10-minute 5-155 min 5-155 min 5-155 min 35-155 min 5-95 min 35-95 min 5-35 min 20-minute 95 min 35 min 95 min 35 min 30-minute 95-155 min 155 min 95-155 min 35 min 5-minute nap did not generally show significant benefit 10-minute nap produced effects immediately that lasted over 2 hours 20-minute nap showed some benefits but not until >35 minutes afterward 30-minute nap showed improvement starting >35 minutes afterward 10- and 30-minute naps showed comparable benefits at 3 hours
5-minute 10-minute 20-minute 30-minute Sleep Latency 65 min post nap 125 min post nap 185 min post nap X ~3 min X ~3.5 min X ~ 5 min X ~3.25 min X ~3.75 min Initial mean sleep latency of ~4 minutes 10-, 20-, and 30-minute naps prolonged sleep latency at 1 hour 20- and 30-minute naps prolonged sleep latency at 2 hours No nap duration prolonged sleep latency at 3 hours
Circadian Factors
Circadian Effect on Neurobehavioral Performance Core body temperature nadir at 2-4 am Subjective sleepiness, cognitive performance, and reaction time trough 3-4.5 hours after CBT nadir Core body temperature peak at 4-6 pm Subjective sleepiness, cognitive performance, and reaction time peak around this time
Circadian effect on exercise Exercise-induced increase in epinephrine doubles at 8:30 am compared to 4:30 am Cardiac vagal tone peaks at 7:00-8:00 am and troughs from 6:00-10:30 pm with greatest vagal withdrawal from exercise at 7:00-8:30 am Systolic blood pressure reactivity to exercise peaks at midnight Heart rate increased with exercise without circadian changes Physiological reactivity to exercise was 35-50% for autonomic markers
Increase in CBT associated with Increased energy metabolism with carbohydrate utilization over fat as fuel source Improved muscle compliance Facilitated actin-myosin crossbridging (Starkie 1999) Increasing CBT through warm-ups in the morning can improve physical performance (Taylor 2011, Atkinson 2005) Doesn t compensate for time of day difference from morning to early evening Time-of-day effects seen in multiple studies involving swimming, cycling, soccer, racquet sports
The Impact of Circadian Misalignment on Athletic Performance in Professional Football Players Smith RS, Efron B, Mah CD, Malhotra A. SLEEP. 2013 Dec 1;36(12):1999-2001. Efron B Efron Z
West Coast vs East Coast
West Coast vs East Coast 40 years of NFL games WC vs EC games with start times after 8 pm EST 106 total games Set 1: 1970-1994, 64 games Set 2: 1995-2011, 42 games Las Vegas point spread used to account for known variables Variable x = WC team score EC team score + point spread Positive x = WC team beat the point spread Negative x = WC team did not beat the point spread Control group used 293 daytime games involving same WC vs EC match-ups
Results Data showed a strong advantage for WC teams over EC teams even accounting for the point spread Set 1: x was significantly greater than 0 (P=0.009) Set 2: x was significantly greater than 0 (P=0.006) Combined data set: WC teams beat EC teams beyond the point spread (P<0.0001) WC teams beat the point spread in 70 games vs. 36 games for EC teams No similar advantage seen in daytime games WC teams beat the point spread in 143 games vs. 150 games for EC teams
What about the Utah Jazz?
2015-2016 Stats Overall Record 40-42 Western Conference Record 24-28 Eastern Conference Record 16-14 Pacific Mountain Central Eastern 3-6 28-17 5-11 4-8 Before 5 pm 5 pm 6 pm 7 pm 8 pm 4-1 5-9 3-9 25-17 3-6
8-21 10-14 20-8
Surprises WINS Cavaliers - 8:30 pm home game (10:30 pm EST) Celtics 8:30 pm home game (10:30 pm EST) Raptors 7 pm home game (9 pm EST) Heat 7 pm home game (9 pm EST) Hornets 7 pm home game (8 pm CST) Clippers 7:30 pm away game (8:30 pm MST) Hawks 4 pm away game (2 pm MST) Hornets 6 pm away game (5 pm MST) LOSSES Lakers 7:30 pm away game (8:30 pm MST) Kings 7 pm away game (8 pm MST) Kings 7 pm home game (6 pm PST) Knicks 7:30 pm away game (5:30 pm MST) Nets 7:30 pm home game (9:30 pm EST) Pelicans 7 pm home game (8 pm CST) Pelicans 7 pm away game (6 pm MST) T-wolves 7 pm away game (6 pm MST)
What Did I Learn? The Jazz should schedule all EST teams for games here at 8:30 pm With that exception They should try to play more games before 5 pm and fewer games after 8 pm They should play all their other home games at 7 pm They should not play a superstar in his final NBA game especially after 8 pm
Conclusions Sleep is a vital aspect to one s athletic and cognitive performance but yet its not being emphasized enough Brief daytime naps can improve cognitive function up to a few hours after Athletic performance can improve when aligned with the optimal circadian schedule Plenty of research still needs to be done