SLEEP 2011 Abstract Supplement

B. Clinical Sleep Science II. Sleep Disorders – Circadian Rhythms
Morningness Eveningness Questionnaire (MEQ) is a method for assessing
chronotype. Because Major League Baseball (MLB) players play
games both during the day and night, it was hypothesized that chronotype
might predict optimal batting performance times.
Methods: MEQ data from 16 MLB batters representing 7 teams was
collected. A modified 7 question MEQ (mMEQ) was obtained by adding
the score of question 7 (subject global impression) to the total score.
Statistical performances from the 2009 and 2010 seasons were logged
with game start times adjusted for travel using the convention that for
every time zone traveled, it takes 24 hours to adjust. Games were divided
into two groups. ‘Early’ games featured start times prior to 14:00,
‘Mid’ games between 14:00-19:59, and ‘Late’ games began at 20:00 or
after. This produced 2149 early innings, 4550 mid inning, and 750 late
innings. 16 players were divided into two groups: 9 ‘evening type’ players
[E-types] (mean age = 29.0, SD = 3.4, mMEQ score of 12-23), and
7 ‘morning type’ players [M-types] (mean age = 29.0, SD=4.1, mMEQ
of 24-33).
Results: In early games, M-type batters had an average of .267 compared
with an E-type average of .259. In mid games, M-type batters had
an average of .252 and E-type batters an average of .261. In late games,
M-type batters had an average of .252 and E-type batters an average of
.306.
Conclusion: Other investigations have shown tendencies for M-type
athletes to perform significantly better in the morning versus the evening.
Our results showed a similar trend. Because of the small magnitude
of the effect we are studying, we plan on looking at more players
and precise batting times to better understand this effect.
0489
NATURAL CIRCADIAN PHASE-SHIFTS DURING SUMMER
NIGHTWORK IN POLICE OFFICERS ASSIGNED TO
ROTATING SCHEDULES
Martin J, Sasseville A, Lavoie J, Houle J, Hébert M
Centre de recherche Universite Laval Robert Giffard, Quebec, QC,
Canada
Introduction: It is often reported that night shift workers usually do
not adapt to the night schedule due to the resynchronising effect of light
during the commute home combined with low light exposure at night in
the workplace. However, police officers who are patrolling at night do
experience some natural light towards the morning especially in summer
time. It is unclear if this light which may starts as early as 4AM may
cause phase-delay or if it would be counterbalanced by light received
later in the morning. This study investigated the phase-shift experienced
by patrol police officers with DLMO obtained before and after a series
of 4 night shifts in summer time in Quebec city (latitude 46°49.2’N).
Methods: Salivary samples were obtained before and after 4 consecutive
night shifts in 13 officers (mean age 28.5±2.67). Pre-night shifts
(hourly) collection went from 19h00 to 23h00 whereas post-night shifts
collection went from 21h00 to 04h00 (in order to detect an expected
phase-delay). Elisa was used to assay melatonin concentration. Police
officers were assessed between May and October and wore a wrist photometer
to measure ambient light. Work schedule was 23h00-07h00.
Results: DLMO before the night shift range from 20h00 to 23h00 with a
mean of 21h10±0h41. Phase-shift ranged from 1 to 7 hours with a mean
of 3h02±1h46. There was no correlation between the amount of phaseshift
experienced and sunrise which varied (during the experiment) from
04h50 in June and 07h15 in October. Interestingly the police officer
tested in October showed a 3h30 phase-delay.
Conclusion: Preliminary analysis revealed that substantial phase-shifts
could observe in some patrol police officers whereas very small phaseshifts
are observed in others. Light exposure analysis shall provide more
information regarding the possibility that light intensity received in
morning or evening (before the night shift) could explain this variability.
0490
OBSTRUCTIVE SLEEP APNEA AND NON-DIPPING
NOCTURNAL BLOOD PRESSURE
Seif F 1 , Patel SR 2 , Bhatt DL 4 , Blumenthal R 6 , Gottlieb DJ 5 , Lewis EF 3 ,
Patil SP 7 , Quan SF 2 , Redline S 2 , Mehra R 1
1
Division of Pulmonary, Critical Care and Sleep Medicine, University
Hospitals Case Medical Center, Cleveland, OH, USA, 2 Division of
Sleep Medicine, Brigham & Women’s Hospital, Boston, MA, USA,
3
Division of Cardiology, Bringham & Women’s Hospital, Boston, MA,
USA, 4 Division of Cardiology, VA Boston Healthcare System, Boston,
MA, USA, 5 Division of Pulmonary and Sleep Medicine, VA Boston
Healthcare System, Boston, MA, USA, 6 Division of Cardiology, Johns
Hopkins University, Baltimore, MD, USA, 7 Division of Pulmonary and
Sleep Medicine, Johns Hopkins University, Baltimore, MD, USA
Introduction: The relationship of obstructive sleep apnea (OSA) and
the absence of normal physiologic sleep-related blood pressure (BP)
dipping has not been specifically characterized in those with cardiovascular
(CV) risk. We hypothesize that increasing OSA severity is associated
with non-dipping BP during sleep in those with increased CV risk.
Methods: Data are from participants of the baseline visit of a multicenter
randomized controlled trial (Heart Biomarker Evaluation in Apnea
Treatment: HeartBEAT). OSA severity was assessed using the apnea
hypopnea index (AHI). BP dipping from 24-hour ambulatory BP monitoring
was defined as a sleep-related BP reduction of > 10% (i.e., sleepwake
BP ratio of