Effects of short nap and exercise on elderly people having difficulty in sleeping

Authors


Correspondence address: HidekiTanaka Department of Psychogeriatrics, National Institute of Mental Health, National Center of Neurology and Psychiatry, 1-7-3, Kohnodai, Ichikawa-city, Chiba 272-0927, Japan. Email: tanaka@ncnp-k.go.jp

Abstract

The purpose of the present study was to examine the effects of short nap and exercise on the sleep quality of elderly people who reported difficulty in sleeping. ‘Interventions’ such as short nap after lunch and moderate-intensity exercise in the evening were carried out for 4 weeks. After the ‘interventions’, wake time after sleep onset significantly decreased and sleep efficiency significantly increased, which showed that sleep quality was improved. The frequency of nodding in the evening significantly decreased. These results demonstrated that the proper awakening maintenance in the evening was effective in improving sleep quality. After the ‘intervention’, mental health was also improved with improving sleep quality.

INTRODUCTION

Sleep disorders in elderly people hinder their social adaptation and activities in the community, and constitute a serious problem with regard to the maintenance of quality of life. Sleep disorders are among the most common difficulties facing elderly people, whose primary goal is to maintain a healthy, independent lifestyle. We conducted the investigative research on the lifestyle factors that influence sleep quality.1 The results demonstrated that lifestyle, habits, including moderate exercise such as walking in the evening, and a short nap (30 min between 13:00 and 15:00), are important in the maintenance and improvement of sleep quality, and that sleep quality is closely related to physical and mental health. We also suggested that improvement of nocturnal sleep is related to proper awakening maintenance. The purpose of the present study is to examine the effects of a short nap and moderate-intensity exercise in the evening on the sleep quality of elderly persons who have difficulty in sleeping.

METHODS

The subjects were six elderly people (72.0 ± 5.2 years) who gave informed consent for their participation, out of nine elderly people who had reported sleep difficulties and participated in a previous study.1‘Intervention’ by a short nap after lunch (30 min between 13:00 and 15:00) and moderate-intensity exercise in the evening, including stretching and flexibility (30 min from 17:00) were carried out for 4 weeks in the winter. All subjects were able to lead a normal life at home, and screening tests before the ‘intervention’ were used to exclude those who experienced sleep problems due to illness. Their physical activities were recorded using actigraphs for 1 week pre- and post-intervention. Actigraph data were analyzed to determine ‘sleep’ and ‘wake’ periods by applying a Cole’s validated algorithm2 to the portions of the records identified as sleep periods by the combination of sleep logs. Mental health was assessed using the General Health questionnaire (GHQ).3

RESULTS

After the ‘intervention’ (Table 1), wake time after sleep onset significantly decreased and sleep efficiency significantly increased, showing that sleep quality was improved. The frequency of nodding in the evening significantly decreased. Furthermore, the subjects’ subjective daytime sleepiness was reduced after the ‘intervention’. Their GHQ score also significantly decreased (from 5.6 ± 1.1 to 1.6 ± 0.9; P < 0.05), showing that their mental health was also improved.

Table 1.  Comparison of actigraph data between pre- and post-intervention
 PrePostSignificance
  1. Values are expressed as mean ± SEM.

Wake time after sleep onset (min)83.2 ± 23.428.2 ± 4.31P < 0.01
Sleep efficiency (%)73.9 ± 4.2489.7 ± 1.70P < 0.01
Nodding in the evening (min)39.3 ± 13.0010.9 ± 6.69P < 0.10
Nodding above 5 min. (frequency)1.7 ± 0.410.5 ± 0.24P < 0.05

DISCUSSION

After the ‘intervention’, sleep quality was improved and the frequency of nodding in the evening significantly decreased. These results demonstrated that the proper awakening maintenance during evening was effective in improving sleep quality. Until recently, it was considered that taking a nap has a negative effect on the nocturnal sleep. However, a short nap of 30 min between 13:00 and 15:00 has little quantitative effect on nocturnal sleep. Moreover, a short nap is effective for recovery of attention, concentration and brain function.4 The present results reconfirmed that habitually taking a short nap is effective in maintaining sleep quality,1,4 and indicated that napping is an effective way for elderly people to maintain the sleep. The body temperature phase of elderly people is advanced 2–3 h ahead of that of young people.5 Moreover, the existence of a ‘forbidden zone’ was demonstrated.5 This ‘forbidden zone’ is the time period in the vicinity of the highest value of body temperature, and it corresponds to the peak of muscle and exercise capacity.6 It is considered that this time zone occurs around 17:00, and that exercise around this time is effective for improving sleep quality of elderly people. It is also considered that exercise in the evening increases the activity of the arousal system in the ‘forbidden zone’. It is considered that arousal maintenance in the afternoon may be recovered by the short nap, and that the quality of the daytime arousal of the elderly people in the present study was improved by exercise in the evening. As a result, the frequency of nodding before going to sleep decreased, and the quality of nocturnal sleep was improved. After the ‘intervention’, mental health was also improved with improving sleep quality. These results suggest that this ‘intervention’ technique is effective for elderly people.

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