Why We Nap: Evolution, Chronobiology, and Functions of Polyphasic and Ultrashort Sleep

292 Pages·1992·6.12 MB·English

by  Claudio Stampi (auth.)

Editor
Claudio Stampi
Why we nap
Evolution, Chronobiology and Functions
of Polyphasic and Ultrashort Sleep
WHYWENAP
Evolution, Chronobiology,
and Functions of
Polyphasic and Ultrashort Sleep
WHY WE NAP
Evolution, Chronobiology,
and Functions of
Polyphasic and Ultrashort Sleep
Claudio Stampi
Editor
Foreword by Jürgen Aschoff
68 Illustrations
Springer SciencetBusiness Media, LLC
Claudio Stampi
Sleep and Alertness Research Unit
Institute for Circadian Physiology
677 Beacon Street
Boston, MA 02215-3203
USA
Library of Congress Cataloging-in-Publication Data
Why we nap: evolution, chronobiology, and functions of polyphasic and
ultrashort sleep / Claudio Stampi, editor.
p. cm.
1ncludes bibliographical references and index.
1. Naps (Sleep) 1. Stampi, Claudio, 1953-
QP427.W48 1992
612.8'21-dc20 92-23206
CIP
Printed on acid-free paper.
© Springer Science+Business Media New York 1992
OriginaIly published by Birkhăuser Boston in 1992
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ISBN 978-1-4757-2212-3 ISBN 978-1-4757-2210-9 (eBook)
DOI 10.1007/978-1-4757-2210-9
To Alessandra
who provided me with a unique
opportunity to observe the human
innate ability to live in a polyphasic
world, and
to Diana
who, as a result, demonstrated how
easy it is to break the habitual
monophasic nocturnal sleep
when the motivation is strong enough
Contents
Foreword............................................................................. ix
Jürgen Aschoff
Preface................................................................................ xv
Claudio Stampi
Contributors......................................................................... xxi
1. Evolution, Chronobiology, and Functions of Polyphasic
and Ultrashort Sleep: Main Issues ...................................... .
Claudio Stampi
I. Evolution, Development, and Regulation
of the Sleep-Wake Cycle
2. Thermoregulation and Control of the Ultradian
Wake-Sleep Cycle............................................................. 23
Pier Luigi Parmeggiani
3. The Phasing of Sleep in Animals ........................................ 31
Nige/ J. Ball
4. Sleep-Wake Rhythms and Sleep Structure
in the First Year of Life ........................ ............ ................ 50
Piero Sa/zarulo and lgino Fagioli
5. Developmental Aspects and a Behavioral Model
of Human Sleep............. ... . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .. . . . . . . ........ 58
Wilse B. Webb
viii Contents
II. Circadian and Ultradian Components of the Sleep-Wake System
6. The Timing and Structure of Spontaneous Naps .................... 71
Scott S. Campbell
7. The Impact of Irregular Sleep-Wake Schedules on Circadian
Rhythms and the RoJe of "Anchor" Sleep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
D. S. Minors and J. M. Waferhause
8. Beyond Circadian Regulation: Ultradian Components
of Sleep-Wake Cycles........................................................ 102
Peretz Lavie
9. Adult Napping and Its Effects on Ability to Function ............. 118
David F. Dinges
III. Polyphasic and Ultrashort Sleep
and Their Effects on Performance
10. The Effects of Polyphasic and Ultrashort Sleep Schedules ........ 137
Claudio Stampi
11. Leonardo da Vinci and Ultrashort Sleep: Personal Experience
of an Eclectic Artist.......................................................... 180
Giancarlo Sbragia
12. What Is the Limit for Prolonged Sleep Reduction?
An Objective Evaluation of the Leonardo da Vinci
Ultrashort Sleep Strategy... .. . ............. ........ ....... .............. ... 185
Claudio Stampi
IV. Irregular Schedules, Sustained Operations, and Napping
13. Minimal Sleep to Maintain Performance: The Search
for Sleep Quantum in Sustained Operations . . . . . . . . . . . . . . . . . . . . . . . . . . 199
Paul Naitoh
14. Sustained Operation Studies: From the Field
to the Laboratory............................................................. 217
R. G. Angus, R. A. Pigeau, and R. J. Heslegrave
V. Polyphasic Behavior, Napping, and Sleep Disorders
15. Napping Behavior in Narcoleptic Patients:
A Four-Hour Cycle in Slow Wave Sleep ............................... 245
M. Billiard, J. De Koninck, D. Coulombe, and A. Touzery
16. Narcolepsy and the Pathological Aspects
of Multiple Napping......................................................... 258
Hartmut Schutz, Johanna Wilde-Frenz, Stephan Volk,_
and Peter Geister
Index.................................................................................. 271
Foreword
J AscHOFF
ÜRGEN
"Very bad habit! Very bad habit!"
Captain Giles to Joseph Conrad
who had taken a siesta.
-Conrad: The Shadow Line
On the Multiplicity of Rest-Activity Cycles:
Some Historical and Conceptual Notes
According to its title this book tries to answer the profound question of why
we nap-and why Captain Giles was wrong in blaming Conrad for having
napped. However, in this volume the term nap is not used in the narrower
sense of an afternoon siesta; instead, emphasis is placed on the recurrent
alternation between states of alertness and drowsiness, i.e., on rest-activity
cycles of high er frequency throughout the 24 hr. In view of this focus, two
authors (Stampi, in Chapter I, and Ball, in Chapter 3) rightly refer to the
psychologist Szymanski who was among the first to describe "polyphasic"
activity patterns. Hence, I consider it appropriate to open this foreword
with a few historical remarks.
At the time when Szymanski (1920) made the distinction between
"monophasic" and "polyphasic" rest-activity patterns and sleep-wake cy
cles, respectively, not much was known about the mechanisms of such
temporal structures. Although the botanists quite some time ago had
demonstrated the endogenous nature of the "monophasic" sleep movements
in plants, the hypothesis of an (still unknown) external driving force was
favored by those who studied rhythms in animals and humans (Aschoff,
1990). It must be noted, however, that Szymanski himself, summarizing his
x Foreword
recordings of activity in children and adults within a range from minutes to
hours, derived the "principle of activity by internal needs," and even used
the term organische Uhr (organic clock): "The fluctuations in the disposi
tion to work ... constitute the mechanism of that organic clock from
which consciousness reads the time" (Szymanski, 1922; my translation from
German). He also came close to the notion of a system which later on was
called circadian (Halberg, 1959). Once he had kept a canary in continuous
darkness (DD) for 73 days, and he found that not only did the (mainly)
monophasic rhythm persist butthat its phase eventually was shifted by 6 hr.
In view of these findings he posed the question of whether it might be
possible that, in DD, a "new type of rest-activity cycles emerges which
deviates from the norm" (Szymanski, 1914).
In his studies on humans, Szymanski made use of spring-suspended beds
and chairs which allowed him to record movements of all kinds of
frequencies, down to respiration. Apart from the main sleep-wake cycle, he
noticed a prominent rhythm with a period of 2.5 hr during wakefulness and
sleep, with bouts of activity separated by pauses of about 45 min, and
superimposed by faster rhythms in the range of minutes. He also observed
that, intraindividually, the variability of the various rhythmic components
increased as the periods became shorter (Szymanski, 1922). This concurrent
representation of activity rhythms with different frequencies becomes most
obvious in typically polyphasic species such as rodents. The period that can
be extracted from a record depends on the recording device and on the
temporal scanning grid applied in the analysis. The actagram of a mause,
recorded with a spring-suspended cage under a light-dark cycle (LD),
reveals a "pure polyphasic" (cf. Stampi, Chapter 1, this volume) pattern
with 12 bouts of activity per 24 hr when the data are summarized in 10-min
bins; in the same set of data, a period of approximately 4.5 hr appears (with
only minor variations in amount of activity from L to D) when a 1-hr grid
is applied; finally, the typical circadian pattern (with two nocturnal peaks)
becomes evident when the data are organized in 2-hr bins (cf. Fig. 1 in
Aschoff, 1957).
The very fact that rhythms of quite different frequencies coexist in the
behavior of an individual, and often interact with each other (cf. later), is
not at variance with our present view that we are dealing with at least two
distinctly different classes of rhythms. There is, on the one band, the
circadian system that evolved in adaptation to time structures in the
environment, which is driven by a localized pacemaker (or a set of
pacemakers) within the central nervaus system, and the period of which,
when measured in constant conditions, usually does not differ by more than
±3 hr from an overall mean of about 24 hr (Aschoff et al., 1982). On the
other hand, there is a variety of rhythms whose periods range from 1 to > 5
hr, which have no immediate relationship to periodicities in the environ
ment, and for which it is unlikely that they are controlled by a common
mechanism (Schulz and Lavie, 1985; cf. also later). The period of these
Foreword xi
"ultradian" rhythms is said to be I 0 tim es more variable than the circadian
period (Gerkema and Daan, 1985), and it is obviously more affected by
internal as weil as external factors. As has been shown in birds and
mammals, the frequency of an ultradian rhythm may depend on food
availability, on period and phase of the circadian rhythm, and on the
season, either by direct effects of the changing photoperiod or via changes
in the circadian system. Furthermore, a phase-setting effect on ultradian
rhythms by the circadian system has been demonstrated in 8 mammalian
species (for references, see Aschoff and Gerkema, 1985). The reverse
possibility, i.e., a shift in phase of the circadian rhythm by an ultradian
bout of activity, has been suggested by a few actograms of voles (cf. Fig. 4
in Gerkema and Daan, 1985).
In spite of bidirectional interactions between the two classes of rhythms,
there is no doubt that ultradian rhythms can be expressed independently of
the circadian system. This Statement is based on two sets of Observations.
During ontogeny, as weil as during the emergence of hibernating mammals
from torpor, ultradian rhythms appear prior to the circadian rhythm, and
there are data which indicate that, at old age (and during entrance into
hibernation?), the circadian system may become disintegrated, with only
ultradian components being left. From this sequence of events, it could be
concluded that the ultradian time structure is more "basic" than the
circadian one. However, one has to remernher that the appearance or
disappearance of an overt rhythm does not necessarily reflect a change in
the state of the generating mechanism; it may also be due to a coupling or
uncoupling of the behavioral element to or from an ongoing central
rhythm, as demonstrated in hibernating mammals by the episodic awaken
ings timed on a circadian scale (Pohl, 1964; Daan, 1973). In the rat, the
circadian pacemaker is rhythmic prenataily and prior to its expression in an
overt rhythm (Fuchs and Moore, 1980). In view of such uncertainties in
defining "priorities" in the development of rhythms, the notion of an
independent ultradian system is more rigorously supported by the Observa
tion that ultradian rhythms persist, and may even be more clearly expressed,
in animals which have lost circadian rhythmicity after lesions of the
suprachiasmatic nuclei (Gerkema and Daan, 1985; Honma and Honma,
1985). lt remains to be seen whether these rhythms are driven by real
pacemakers (cf. several chapters in Schulz and Lavie, 1985). In the vole, the
retrochiasmatic area and the arcuate nucleus seem to be essential for the
expression of ultradian rhythms in wheel-running and feeding (Gerkema et
al., 1990).
The multiplicity of periods represented in ultradian rhythms, their
nonstationarity, and the often inconsistent interrelationships among the
components, impede attempts to arrive at a unifying concept of mecha
nisms. The theory of a Basic Rest-Activity Cycle (BRAC), advanced by
Kleitman (1961), presupposes rhythmicity of about 90 min during wakeful
ness as weil as during sleep, which is based on a common generating