Sleep, Dreaming, and Adaptation to a Stressful Intellectual Activity

Abstract

Summary: Sixteen male subjects slept in the laboratory for 4 consecutive nights. Night 1 was an adaptation night and night 2 waS a baseline night of uninterrupted sleep. On nights 3 and 4 subjects were asked to complete "intelligence" tests prior to sleep. One half of the subjects attempted to complete difficult versions of "intelligence" tests without knowing that they could not be completed in the time allotted. The other subjects were given easier versions of the same tests that they were able to complete in the time allotted. Night 3 was a night of uninterrupted sleep and night 4 involved REM period awakenings for the purpose of dream collection. Stressful manipulation consisted of telling the subjects before the administration of either set of tests that an average university student should complete most of the items within the allotted time. On night 3 both groups showed a significant increase in sleep latency and a significant decrease in REM density compared to the baseline night. On night 4 subjects in the difficult condition experienced significantly more anxiety in their dreams and somewhat higher levels of incorporation of the presleep material than subjects in the easy condition. Our findings suggest that following a stressful experience uninterrupted sleep has more short term adaptive value than a procedure which enhances dream recall and that subjects who incorporate elements from a presleep stressful event into their remembered dreams show less adaptation on awakening than subjects who do not. Key Words: Adaptation-Pre-and postsleep anxiety-Stress.In recent years a host of studies have focused on the interplay between waking and sleeping lives. Most studies have examined the effects of a large variety of artificially induced and naturally occurring presleep stressful events on the physiology of sleep and/ or dream content and dream affect (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Although the results have not been very consistent from study to study, the observed effects include increases in the latency to sleep onset, decreases in latency to REM sleep, decreases in the percentage of REM sleep, changes in dream affect, and incorporation of stressful elements into dreams.Some of these studies (7,8,12,13) have asked the additional question of how events during sleep affect subsequent waking experience. Greenberg et al. (12) presented a stressful film to three groups of subjects before they went to sleep and again in the morning. During the night one group of subjects was deprived of REM sleep, another was awakened during NREM sleep, and the third group was allowed to sleep without interruption. The REM-

The influence of pre-sleep cognitive arousal on sleep onset processes

“…Ansfield et al (1996) found that under high mental load (March music) the urgency to fall asleep increased sleep onset latency in normal subjects whilst under a low mental load (new age music) the urgency to fall asleep caused subjects to fall asleep sooner than without the urgency under the same mental load. Kobayashi et al (1998) found that mental activity affected the timing of REM-periods later at night and Koulack et al (1985) found that both easy and difficult versions of intelligence tests increased subsequent sleep onset latency and negatively influenced REM density. Moreover, presleep engagement in exciting computer games increased sleep onset latency (Dworak et al, 2007;Higuchi et al, 2005).…”

“…Yet, these studies did not differentiate between the pure cognitive effects of inducing cognitive arousal and the possible consequences of arousing emotional factors (Vandekerckhove and Cluydts, 2010) in their inductione.g. a financial reward (Hauri, 1968), the stress of a 15-minute evaluated speech in the morning (Hall et al, 1996), musical preference (Ansfield et al, 1996), a television interview (De Valck et al, 2004) or speech (Gross and Borkovec, 1982), driving a car for 600 km on the highway (Kobayashi et al, 1998), fear of failure (Koulack et al, 1985) and playing shooting (Higuchi et al, 2005) or race games (Dworak et al, 2007). Research has shown that cognitive tasks with no emotional load (i.e.…”

The Effect of Psychosocial Stress on Sleep: A Review of Polysomnographic Evidence

“…More recently, Koulack, Prevost, and De Koninck (1985) gave an intellectually challenging test to 16 male university students; the suggestion of inferiority led to longer SL and lower REM density than at baseline. Germain, Buysse, Ombao, Kupfer, and Hall (2003) reported that acute experimental psychological stress reduced rapid eye movement counts during the last REM sleep period in healthy participants when compared to non-stressed control participants.…”

“…In the 1960s and 1970s, many researchers reported that presleep stimulation influenced REM activity and awakenings (Baekeland, Koulack, & Lasky, 1968;Cluydts & Visser, 1980;Cohen, 1975;Goodenough, Witkin, Koulack, & Cohen, 1975). Pre-sleep stress, such as an aversive film (Baekeland et al, 1968;Cluydts & Visser, 1980;Goodenough et al, 1975;Lauer, Riemann, Lund, & Berger, 1987) or impersonal treatment (Cohen, 1975), was associated with increased frequency of rapid eye movements (REM density; Goodenough et al, 1975;Lauer et al, 1987), number of awakenings (Baekeland et al, 1968;Cluydts & Visser, 1980), and longer SL (Goodenough et al, 1975).More recently, Koulack, Prevost, and De Koninck (1985) gave an intellectually challenging test to 16 male university students; the suggestion of inferiority led to longer SL and lower REM density than at baseline. Germain, Buysse, Ombao, Kupfer, and Hall (2003) reported that acute experimental psychological stress reduced rapid eye movement counts during the last REM sleep period in healthy participants when compared to non-stressed control participants.…”

Evidence for the preferential incorporation of emotional waking-life experiences into dreams.

“…For example, dreams are very clearly affected by traumatic experiences (see reviews by, for example, Barrett (1996) and Punamäki (2007)), and other more common stressful waking-life experiences such as surgery (Breger, Hunter, & Lane, 1971) and divorce (Cartwright, 1991(Cartwright, , 2011Cartwright et al, 1984;Cartwright et al, 2001;Cartwright et al, 2006). However, while some experimental studies have found measurable effects of stressful experiences on dreams, mostly in terms of dream affect (de Koninck & Brunette, 1991;de Koninck & Koulack, 1975;Koulack et al, 1985), a naturalistic study found no effect either in terms of direct or indirect incorporations, or changes to dream affect (Delorme et al, 2002). The authors of the latter study suggested that the stress created by examinations (the stressor) may not have been great enough to elicit direct incorporations.…”