Research Institute for Sport & Exercise Sciences FACULTY OF SCIENCE Circadian rhythms and swimming...

Research Institute for Sport & Exercise SciencesFACULTY OF SCIENCE

Circadian rhythms and Circadian rhythms and swimming performanceswimming performance

Greg AtkinsonGreg AtkinsonChronobiology Research GroupChronobiology Research Group

Research Institute for Sport and Exercise SciencesResearch Institute for Sport and Exercise Sciences

Liverpool John Moores UniversityLiverpool John Moores University


ContentsEvidence for endogenous diurnal variation in swimming performance?

“Optimising performance”:Jet-lag

Morning ↓ performance:• Overridden with warm-ups?• Shifted with exercise, bright

light and/or melatonin?


Swimming performances: morning heats vs evening finals

Pyne et al. J Sports Sci 2004; 22: 613-620


Controlled time trials

71

71.5

72

72.5

73

73.5

74

74.5

75

75.5

76

06:30 09:00 13:30 17:00 22:00

100-

m t

ime

(s)

324

326

328

330

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334

336

338

340

400-

m t

ime

(s)

100 m

400 m

Baxter and Reilly, Brit J Sports Med 1983; 17: 122-127

3.5%

↑2.5%


Edwards et al., Chronobiol Int 2002; 19: 579-597

Measuring endogenous component:Constant routines

Time of day (h)

36

36.5

37

37.5

38

12 14 16 18 20 22 24 2 4 6 8 10 12

Bo

dy

tem

per

atu

re (

°C)

Sleep


Edwards et al., Chronobiol Int 2002; 19: 579-597

Time of day (h)

36

36.5

37

37.5

38

12 14 16 18 20 22 24 2 4 6 8 10 12

Bo

dy

tem

per

atu

re (

°C)

Measuring endogenous component:Constant routines

Awake


Kline et al. J Appl Physiol 102: 641–649, 2007.

Semi-constant routine approach

2.3%


The underlying circadian system


Bodyclock

Intergeniculateleaflet

Activityrhythm

Retino-Hypothalamic

tract

Lightrhythm

Melatonin Pinealgland

Vision

The working model

Waterhouse et al., Keeping in time with your body clock, Oxford University Press

Outputs


Bodyclock


Activityrhythm

Retino-Hypothalamic

tract

Lightrhythm


Vision

The working model


OutputsMas

king


1240

1280

1320

1360

1400

1440

1480

1520

1560

Control Warm-up

Per

form

ance

tim

e (s

) Morning

Afternoon* *

#

Masking the body clock with a warm-up?

Atkinson et al. J Sports Sci 2005; 23: 321-329

**


Bodyclock


Activityrhythm

Retino-Hypothalamic

tract

Lightrhythm


Vision

The working model



A ‘phase-response curve’ for exercise?

Atkinson et al. Eur J Appl Physiol 2007; 99: 331-341

Approx4am


Timing of morning exercise in the taper phase?

1 2 3 4 5 6 7 8 9 10

Edwards et al., Int J Sports Med 2005; 26: 651-656

2%


Bodyclock


Activityrhythm

Retino-Hypothalamic

tract

Lightrhythm


Vision

The working model



Phase-response curve for light

Waterhouse et al. Neurosci Let 1998; 245: 97-100

Approx4am


Evening bright light delays the body temperature rise

Atkinson et al., Int J Sports Med 2008; 29: 188-193

BrightLight


Bodyclock


Activityrhythm

Retino-Hypothalamic

tract

Lightrhythm


Vision

The working model



Phase response curve for melatonin

-1.5

-1

-0.5

0

0.5

1

1.5

0 5 10 15 20 25

Circadian time (h)

Ad

va

nc

eD

ela

y

Approx4am


Melatonin is a hypnotic!

380

400

420

440

460

480

500

520

540

13:00 17:00

Re

act

ion

tim

e (

ms)

Melatonin

Placebo

M or P

Atkinson et al. Ergonomics 2005;48:1512-1522

11:15


Dietary melatonin

Hardeland and Pandi-Perumal, Nutr Metab 2005;2:1-15


Summary• Good evidence for endogenous circadian variation in

swimming performance

• Variation not completely ameliorated by warm-up interventions

• Timing of circadian rhythm might be manipulated by careful timing of reliable and safe synchronisers to circadian system– Bright light– Exercise– Dietary melatonin?


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)?


Thanks to:

Mike PeyrebruneClare Todd

Ben EdwardsDave Barr

Helen Jones


Martin and Thompson, Int J Sports Med 2000; 21: 387–392

Is the circadian variation robust?


Synchronisers of the human circadian system


Measuring endogenous component:2. Temporal isolation

“Mammoth Cave”, Kentucky Temporal Isolation Lab, Liverpool


Synthesis of melatonin

Atkinson et al., Sports Med 2003; 33: 809-831


Swim bench performance

0

20

40

60

80

100

120

02:00 06:00 10:00 14:00 18:00 22:00

Time of day (h)

Mea

n p

ow

er (

W)

Reilly and Marshall J Swim Res 1991; 7: 11-13

16%


Is the circadian variation resistant to change?

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Afternoon-only Morning+Afternoon

Training schedule

91

.4-m

tim

e (

s)

06:15

17:00

Arnett, J Strength Con Res 2001; 15: 127-131

↑ 1.1%

Research Institute for Sport & Exercise Sciences FACULTY OF SCIENCE Circadian rhythms and swimming...

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