RGUHS Nat. J. Pub. Heal. Sci Vol No: 9 Issue No: 4 eISSN: 2584-0460
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1Abhinandan C Y, Postgraduate student, Department of Physiology, Bangalore Medical College and Research Institute, Bengaluru, Karnataka, India.
2Assistant Professor, Department of Physiology, Bangalore Medical College and Research Institute, Bengaluru, Karnataka, India
*Corresponding Author:
Abhinandan C Y, Postgraduate student, Department of Physiology, Bangalore Medical College and Research Institute, Bengaluru, Karnataka, India., Email: cy.abhi@gmail.com
Abstract
Background: Lack of quality sleep increases the risks of mortality, cognitive impairment, and depression. Pre sleep exercise can disrupt sleep onset as it can lead to high physiological excitement at bed time. Global exercise training guidelines suggest combining both strength and endurance training into training regimen to improve quality of sleep. There is an ongoing debate about the effects of morning versus evening training on sleep quality. The present study aimed to compare quality of sleep among morning and evening strength and endurance trainers.
Aims and Objectives: To assess quality of sleep using a sleep questionnaire in the morning and evening strength and endurance training groups before and after an intervention and to compare the quality of sleep between the groups.
Methods: The study was conducted among 80 healthy, young adults in the age group of 18–30 years who were previously not involved in regular physical activity. They were randomly divided using simple randomization into morning and evening training groups. Subjects included in both the morning and evening groups performed strength and endurance training. The quality of sleep was assessed using Pittsburgh Sleep Quality Index (PSQI) in morning and evening groups, before and after a four-week intervention period. Intergroup comparisons were analysed using relevant statistical tests.
Results: The data collected were analysed using Student t test. The P value for Global PSQI score was found to be statistically significant (P <0.05) in the evening training group and highly significant (P <0.01) in the morning training group.
Conclusion: Though both morning and evening exercise proved to improve quality of sleep, morning strength training was found to be more beneficial towards improving the quality of sleep (sleep initiation and prolongation) when compared to evening exercise.
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Article
Introduction
In recent years, there has been growing attention on the importance of sleep and its essential role in athletic performance, cognition, health and mental wellbeing. It is well known that, appropriate sleep is necessary to maintain physiological and psychological health.1 A lack of quality sleep increases the risk of mortality, cognitive impairment, and depression.2-5 The global exercise training guidelines suggest that combining both strength and endurance training into one’s training programme improves the quality of sleep.6 The time of day when the physical activity takes place affects the quality (initiation) and amount (maintenance) of sleep.7
Some studies have proposed that early morning training session may limit the effectiveness of training because of sleep restriction, whereas others have reported that physical activity in the evening close to bedtime may in turn disturb the subsequent night’s sleep.8, 9 A study found that objective measures of wakeup after sleep onset and total sleep time are associated with the Pittsburgh Sleep Quality Index (PSQI) sleep disturbance component.10
Effects of strength and endurance training on sleep domains, such as sleep quality, sleep continuity, total sleep time, sleep efficiency and day time dysfunction from sleep impairment have been poorly understood. Furthermore, to date, there is insufficient information available on the effect of day specific training modulating the quality of sleep domains, like sleep initiation, maintenance and depth of sleep. The present study aimed to assess the impact of morning and evening strength and endurance training on sleep quality in young, healthy adults over a four week intervention period.
Objectives of the Study
To determine the effect of morning versus evening strength and endurance training on sleep quality in young, healthy adults.
Materials and Methods
After obtaining approval and clearance from the institutional ethics committee, the study was initiated. Eighty subjects were enrolled for the study on a voluntary basis. After each subject was explained about the procedure and the objective of the study, written informed consent was taken.
The present study was conducted among the recruited young, healthy adults who fulfilled the inclusion and exclusion criteria. The subjects were provided with patient information sheet and subsequently underwent clinical examination as per study proforma. Their bodyweight and height were measured. The BMI was calculated as weight in Kgs divided by height in metre square. Their waist circumference was measured. A baseline PSQI questionnaire was given to all the subjects and scores were measured. They were randomly divided using the software randomization.org into morning and evening training groups. An intervention of strength and endurance training was done under the supervision of a certified trainer for a period of four weeks. Post intervention, the quality of sleep was assessed using Pittsburgh Sleep Quality Index (PSQI). Intergroup comparisons were done using relevant statistical test measures.
Strength and endurance exercise protocol11
The two groups received an identical four-week exercise training programme consisting of five sessions of 60 minutes each per week, combining the strength and endurance exercises. Endurance training involved moderate intensity aerobic activity on different equipments (bicycle, treadmill). Strength training session comprised of muscle strengthening circuits targeting all major muscle groups. Each session began with a 10 minute standardized warmup, including dynamic stretching and light aerobic exercises. All sessions were supervised by a certified trainer.
Sleep quality questionnaire
The Pittsburgh sleep quality index (PSQI)12 was measured at baseline and following four-week exercise intervention. PSQI evaluates the quality of sleep based on 19 items covering seven clinically relevant components of sleep difficulties. Each item is measured on a scale, and a global score of sleep quality is calculated by adding up the seven component scores. This produces an overall PSQI score ranging from 0 to 21, where a score > 5 indicates poor sleep quality.
Statistical analysis
• The data collected were analysed statistically using IBM SPSS, Version 29.0
• Comparison between pre and post intervention values within the group and between the groups was done using paired t test.
Results
The mean difference in Global PSQI scores showed a significant improvement in sleep quality in the morning training group compared to the evening training group.
The data collected were analysed using paired t test. The P value for the difference in Global PSQI scores within groups, before and after training, was found to be statistically significant (P <0.05) in the evening training group, and highly significant (P <0.01) in the morning training group.
Discussion
Table 1 and Figure 1 shows statistically significant improvement in the PSQI scores of both the morning and evening training groups. However, this improvement in scores was more notable in the morning training group compared to the evening training group.
One of the fundamental principles of mammalian circadian system is its varying sensitivity to stimuli at different times of day. As a result, the internal circadian rhythm's response to exercise is likely influenced by the timing of that exercise. Exposure to morning light can shift the internal rhythm earlier. Thus combining morning light exposure with morning exercise may have synergistic phase-advancing effect on young adults in everyday situations.13
A study by Matthew Thomas et al., found that those who experience the most severe circadian misalignment may benefit from phase advances induced by exercise in the morning; but evening exercise may exacerbate circadian misalignment.13
A study by Jaehoon Seol et al., found that engaging in low-intensity stepping exercises during evening is a potentially useful nonpharmacological approach to improve sleep quality among older adults.14
However, engaging in moderate-to-vigorous exercise close to bed time can negatively affect sleep, due to the elevation of core body temperature and increased physiological arousal, which can cause phase delays in the circadian system.
Conclusion
Though both morning and evening exercise has a positive impact on sleep quality, morning training is found to be more beneficial towards improving the quality of sleep when compared to evening training.
Given the smaller sample size and shorter duration of the present study, future research assessing sleep quality using polysomnography is recommended.
Conflicts of Interest
None
Supporting File
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