Greg Atkinson 1 and Andrew Thompson 2

Transcription

1 Døgnrytme og svømning ydeevne Greg Atkinson 1 and Andrew Thompson 2 1 Health and Social Care Institute, Teesside University 2 Research Institute for Sport and Exercise Sciences, Liverpool John Moores University

2 How can chronobiology help the swimmer? Circadian rhythms relevant to swimming Can we cure circadian variation? Warm-ups? Bright light? Melatonin? Can we cure jet-lag? US Soccer study

3 How can chronobiology help the swimmer? Circadian rhythms relevant to swimming Can we cure circadian variation? Warm-ups? Bright light? Melatonin? Can we cure jet-lag? US Soccer study

4 Swimming performances in the noisy real world Pyne et al. J Sports Sci 2004; 22:

5 Heats vs Finals (Beijing)? e.g. 400 m Freestyle Final Heat

6 100-m time (s) 400-m time (s) Controlled swimming time trials in the pool m 400 m 3.5% h prior sleep 2.5% :30 09:00 13:30 17:00 22:00 Baxter and Reilly, Brit J Sports Med 1983; 17:

7 Controlling for sleep prior to each test time 2.3% Kline et al. J Appl Physiol 102: , 2007.

8 How can chronobiology help the swimmer? Circadian rhythms relevant to swimming Can we cure circadian variation? Warm-ups? Bright light? Melatonin? Can we cure jet-lag? US Soccer study

9 The circadian system Body clock Melatonin Pineal gland Intergeniculate leaflet Retino- Hypothalamic tract Vision Activity rhythm Outputs Light rhythm Masking Waterhouse et al., Keeping in time with your body clock, Oxford University Press

10 Performance time (s) Curing morning impairment with a warm-up? * Control * # * Warm-up Morning Afternoon Atkinson et al. J Sports Sci 2005; 23:

11 Curing morning impairment with caffeine? Mora-Rodríguez et al.(2012) PLoS ONE 7(4): e33807

12 The circadian system Body clock Melatonin Pineal gland Intergeniculate leaflet Retino- Hypothalamic tract Vision Activity rhythm Light rhythm Waterhouse et al., Keeping in time with your body clock, Oxford University Press

13 A phase-response curve for exercise? Approx 4am Atkinson et al. Eur J Appl Physiol 2007; 99:

14 Timing of morning exercise in the 3-day taper phase before a morning performance? 2% Edwards et al., Int J Sports Med 2005; 26:

15 The circadian system Body clock Melatonin Pineal gland Intergeniculate leaflet Retino- Hypothalamic tract Vision Activity rhythm Light rhythm Waterhouse et al., Keeping in time with your body clock, Oxford University Press

16 Phase-response curve for light Approx 4am Waterhouse et al. Neurosci Let 1998; 245:

17 Evening bright light delays the body temperature rise Bright Light Atkinson et al., Int J Sports Med 2008; 29:

18 Endurance exercise in the heat: Pre-cooling methods Radiation Air temperature and humidity Sweat evaporation Convection Sky thermal radiation Respiratory evaporation Metabolic heat production Blood flow to the skin Conduction Solar radiation Thermal radiation from the ground Reflected solar radiation

19 Evening bright light and sleep quality Variables No light Light No blue light P Assumed sleep duration (min) Actual sleep duration (min) Wake time after sleep onset (min) Actual sleep duration (%) Wake time after sleep onset (%) Sleep efficiency (%) Sleep latency (min) Sleep quality - VAS

20 Phase-response curve for light Approx 4am Waterhouse et al. Neurosci Let 1998; 245:

21 Time Taken (s) Dawn simulation and 4-km time trial Individual Performances Mean 300 Control Condition Dawn Simulation

22 The circadian system Body clock Melatonin Pineal gland Intergeniculate leaflet Retino- Hypothalamic tract Vision Activity rhythm Light rhythm Waterhouse et al., Keeping in time with your body clock, Oxford University Press

23 Synthesis of melatonin

24 Secretion onset of melatonin prior to sleep Thijssen et al. FASEB, In Press

25 Dietary melatonin? Hardeland and Pandi-Perumal, Nutr Metab 2005;2:1-15

26 Tart Cherry and sleep quality Variable Tart cherry trial Placebo trial Significance Total sleep (min) ± ± 97.3 P = Sleep efficiency (%) 79.0 ± ± 20.1 P = Sleep latency (min) 46.5 ± ± 41.5 P = Sleep bouts 31 ± 8 32 ± 9 P = Wake bouts 31 ± 9 32 ± 9 P = Mean sleep bout (sec) ± ± P = Mean wake bout (sec) ± ± P = Marrin, K. PhD Thesis

27 Delay Advance Phase response curve for ingested melatonin Approx 4am Circadian time (h)

28 Reaction time (ms) Melatonin acutely impairs alertness and performance Melatonin Placebo M or P 11:15 13:00 17:00 Atkinson et al. Ergonomics 2005;48:

29 Hypothermic effects of melatonin Study name Statistics for each study Mean and 95% CI Standard Lower Upper Mean error Variance limit limit Z-Value p-value 5.Dawson et al Dawson et al Dawson et al Dawson et al Deacon et al Deacon&Arendt Deacon &Arendt Deacon&Arendt Gilbertetal Krauchi et al McLellan et al McLellan et al McLellan et al Reidetal Satoh&Mishima Satoh&Mishima Satoh&Mishima VanDenHeuveletal VanDenHeuveletal VanDenHeuveletal Favours A Favours B Marrin et al. In preparation

30 Endurance exercise and thermoregulation: pre-cooling methods Radiation Air temperature and humidity Sweat evaporation Convection Sky thermal radiation Respiratory evaporation Metabolic heat production Blood flow to the skin Conduction Solar radiation Thermal radiation from the ground Reflected solar radiation

31 How can chronobiology help the swimmer? Circadian rhythms relevant to swimming Can we cure circadian variation? Warm-ups? Bright light? Melatonin? Can we cure jet-lag? US Soccer study

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33 Summary Good evidence for endogenous circadian variation in swimming performance Variation not completely ameliorated by warmup interventions caffeine? Timing of circadian rhythm might be manipulated by careful timing of reliable and safe synchronisers to circadian system Bright light Exercise Dietary melatonin?

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35 Recommendations for optimizing morning performance It seems sensible to be exposed to bright light and take some exercise in the morning during the taper phase. Minimal exposure to evening bright light and exercise in taper phase Experimentation: Sleep deprivation (prior evening heats + early waking)? Timing of pre-race meals? Individual differences (chronotype)? Melatonin in afternoon?

36 Is the circadian variation robust? Martin and Thompson, Int J Sports Med 2000; 21:

37 Synchronisers of the human circadian system

38 Measuring endogenous component: 2. Temporal isolation Mammoth Cave, Kentucky Temporal Isolation Lab, Liverpool

39 Mean power (W) Swim bench performance :00 06:00 10:00 14:00 18:00 22:00 Time of day (h) 16% Reilly and Marshall J Swim Res 1991; 7: 11-13

40 91.4-m time (s) Is the circadian variation resistant to change? % 06:15 17:00 54 Afternoon-only Training schedule Morning+Afternoon Arnett, J Strength Con Res 2001; 15:

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43 Reaction time (ms) Effects of melatonin on choice reaction time Melatonin Placebo M or P :00 17:00 Atkinson et al. Ergonomics 2005;48:

44 4 km cycling time (s) Effects of melatonin on 4-km cycling performance Melatonin Placebo M or P :00 17:00 Atkinson et al. Ergonomics 2005;48:

45 Melatonin is not an ergogenic aid when ingested immediately before short-term performance and may in fact hinder performance But...

46 Half-time Pre-cooling and prolonged exercise performance Drust et al., Eur J Appl Physiol 2000;81:11-17

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48 Dependent variables Rectal temperature Mean skin temperature Heart rate Blood pressure Blood flow Perceived exertion and alertness * * * * Atkinson et al., J Pineal Res 2005; 39:

49 Temperature ( C) Effects of melatonin on core temperature during exercise Melatonin Placebo Time of day (h) Post Atkinson et al., J Pineal Res 2005; 39:

50 Effects of melatonin on skin blood flow during exercise Melatonin Placebo Atkinson et al., J Pineal Res 2005; 39:

51 Summary We have a body clock which controls circadian rhythms Light alters the timing of the body clock depending on the time it is administered Evening light can delay the morning rise in body temperature useful for pre-cooling? Light may be useful for alleviating jet-lag (timing crucial) Melatonin can also alter circadian timing and can help sleep in some individuals Immediate hypnotic effects of exercise may hinder short-term performances Hypothermic effects of exercise may be useful for precooling athletes

52 plasma glucose (mmol/l) free fatty acids (mmol/l) Melatonin and exercise metabolism Control 0.5 mg/kg 2.0 mg/kg Control 0.5 mg/kg 2.0 mg/kg treatment Treatment Mazepa et al., Life Sci 2000;66:

53 Glycogen (mg/g) Melatonin and exercise metabolism Control 0.5 mg/kg 2.0 mg/kg Treatment Mazepa et al., Life Sci 2000;66:

54 Melatonin alters the growth hormone response to exercise Mel. Pla. Meeking et al., Eur J Endocrin 1999;141:22-26

55 Melatonin alters immune response to exercise Johe and Osterud, J Pineal Res 2005;39:

56 Melatonin is an anti-oxidant Reiter et al., Life Sci 1997;60:

57 Pinealectomy leads to altered exercise response Borges-Silva et al., J Pineal Res 2005;39:

58 Body temperature ( C) Measuring endogenous component: 38 Constant routines Awake Time of day (h) Edwards et al., Chronobiol Int 2002; 19:

59 Body temperature ( C) Measuring endogenous component: Constant routines Sleep Time of day (h) Edwards et al., Chronobiol Int 2002; 19:

60 Circadian Rhythm in Melatonin Arendt, (2005) Research Institute for Sport & Exercise Sciences FACULTY OF SCIENCE

61 Core Temperature ( c) 38 Circadian Rhythm in Body Temperature Time (h) Edwards et al., (2002)

62 Bright Light Therapy Bright light therapy can: Reduce depression scores in SAD patients (Terman, 1990). Delay the body clock when delivered before temperature nadir Advance the body clock when delivered after temperature nadir (Minors et al., 1991). Improve cognitive performance (Phipps-Nelson et al., 2003). Research Institute for Sport & Exercise Sciences FACULTY OF SCIENCE

63 Method 5 physically active subjects (4 M, 1F) (24 ± 7 years) classed as late chronotypes. 2 conditions (with or without dawn simulation). Set sleep and wake-up times to allow 8 h of prior sleep. Dawn simulation initiated 30 min prior to awakening ( lux). 3 cognitive tests at 15, 30 and 75 min post-waking. 4 km self-paced cycling time trial at 60 min post-waking Research Institute for Sport & Exercise Sciences FACULTY OF SCIENCE

64 Measured Outcomes Salivary melatonin (60 min and 5 min before sleep & 0, 15, 30, 45, 60 & 75 min after awakening). Core body temperature (intestinal). Skin Temperature (ibuttons). KSS scores at 1, 5, 15, 30, 45, 60, and 75 min. Cognitive testing Responses, correct and mean reaction time. 4 km time trial Time, RPE, Watts. Data analysed with two factor repeated measures general linear models. Paired t-tests. Research Institute for Sport & Exercise Sciences FACULTY OF SCIENCE

65 Mean Reaction Time (sec) Determination Unit Test Total Additions Work Preference Series ,95 0,9 0,85 0,8 0,75 0,7 Results Cognitive Performance Control Dawn Simulation Cognitive Testing Session

66 Core Body Temperature ( C) 38 37,8 37,6 37,4 37, ,8 36,6 36,4 36,2 Results Core Body Temperature Control Dawn Simulation Stage of Testing

67 The underlying circadian system

68 Melatonin (pg.ml -1 ) Dawn simulation 30,00 Control Dawn Sim 25,00 20,00 15,00 10,00 5,00 0,00-5,00 1hr Presleep Pre-sleep Waking 15 min Post 30 min Post Post TT 60 min Post 75 min Post Time point Research Institute for Sport & Exercise Sciences FACULTY OF SCIENCE