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Effects of endurance and strength exercise on sleep Available at URL: http://www.ismj.com

International SportMed Journal, Vol.12 No.3, 2011, pp. 113-124.

ISMJ International SportMed Journal Original research article

Effects of endurance and strength acute exercise on night sleep quality 1

*Dr Eliana Roveda, MD, 2Dr Chiara Sciolla, PhD, 1Dr Angela Montaruli, PhD, 1Dr Giovanna Calogiuri, PhD, 2Professor Alberto Angeli, MD, 1 Professor Franca Carandente, MD

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Department of Sport, Nutrition and Health Sciences, University of Milan, Malan, Italy Internal Medicine, Department of Clinical and Biological Sciences, University of Turin, Turin, Italy

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*Corresponding author. Address at the end of text.

Abstract Background: Physical activity is one of the lifestyle-related factors that is decisive for the quality of sleep and for immune system stimulation. Research question: The purpose of this research is to evaluate the effect of high-intensity endurance and strength exercises, carried out in the morning, on the quality of nighttime sleep. Methods: Fifteen healthy, trained, males were assessed at rest and during endurance and strength exercises. Preliminarily, at least one week before testing began, maximal oxygen uptake (VO2max) and maximal upper limb strength (maximal weight load, WLmax) were assessed. During each test session continuous monitoring by means of an actigraph for the rest-activity measurement was collected. Results: A single session of strength or endurance exercise positively influenced the parameters related to sleep patterns. The positive effects were particularly evident during the night immediately following the exercise. Both exercise typologies positively influenced the parameters, indicative of the total amount of sleep (assumed sleep and sleep latency). The quality of sleep, evaluated by means of number of sleep bouts, number of immobile phases, and the number of minutes immobile respectively, was also clearly improved during the first night for both types of physical activity. Sleep efficiency was significantly higher during the first and second nights respectively but only following endurance exercise. None of the parameters of sleep have highlighted statistically significant differences between the strength and the endurance sessions. Conclusions: This study shows that morning physical activity has an effect on nighttime rest, making it easier to fall asleep, lengthening the real time of sleep, and improving overall sleep quality. Keywords: physical activity, endurance, strength, actigraphy, sleep

*Dr Eliana Roveda, MD Dr Roveda is an Assistant Professor in Internal Medicine in the Department of Sport, Nutrition and Health Sciences, University of Milan, Milan, Italy. She obtained her medical degree from the University of Milan, and is qualified to teach surgery. She received a Fellowship from the Fondazione Hoechst Marion Roussel.Her main research interests are in chronobiology, didactic activity related to Sports Medicine, First Aid and traumatology all of which she teaches for the degree programme in Sports Sciences at the University of Milan, Italy.

Dr Chiara Sciolla, PhD Dr Sciolla works in Internal Medicine, Department of Clinical and Biological Sciences, University of Turin, Italy. Her initial degree was in Biology, and her main research interests are biomedical 113

Official Journal of FIMS (International Federation of Sports Medicine)



analysis and cell cultures. She is upported by Progetto Lagrange-Fondazione CRT and Antidoping Center Alessandro Bertinaria, University Hospital San Luigi, Orbassano, Turin, Italy. Email: [email protected]

Dr Angela Montaruli, PhD Dr Montaruli is an Assistant Professor in the Department of Sport, Nutrition and Health Sciences, University of Milan, Italy. Her PhD was in Morphological Sciences. Her post-doctoral research was undertaken at the Institute of Human Anatomy (University of Milan). Dr Montaruli is also interested in chronobioliogy, but teaches Human Applied Anatomy and Morphology for the degree programme in Sports Sciences at the University of Milan, Italy. Email: [email protected]

Dr Giovanna Calogiuri, PhD Dr Calogiuri is a member of the Department of Sport, Nutrition and Health Sciences, University of Milan, Italy. He has a PhD in Physical Activity and Sport. His main research interests are Sport Sciences and chronobiology, particularly with regard to adaptation to the absence of light (Arctic Circle) and synchronizing the effects of physical exercise. Email: [email protected]

Professor Alberto Angeli, MD, PhD Professor Angeli is a member of the Department of Clinical and Biological Sciences, University of Turin, Italy. He obtained his degree in Medicine from the University of Turin, and a PhD in Endocrinology and Metabolism from the University of Rome. He is Professor Emeritus in Internal Medicine at the University of Turin. He is a member of the Ethical Committee, University Hospital San Luigi and Piedmont Region, Italy; President of the Academy of Medicine of Turin, and has been the Principal Investigator of many research projects granted by several public and private institutions. He has published widely. Email: [email protected]

Professor Franca Carandente, MD Professor Carandente is a member of the Department of Sport, Nutrition and Health Sciences, University of Milan, Italy. After obtaining his degree in Medicine and Surgery, he specialised in Clinical Allergology and Immunology. He is a Professor of Internal Medicine, and has lectured in chronobiology in the Faculty of Medicine and Surgery, on chronobiology for specialisation schools at the university. He is a Member of the European Society for Chronobiology, and was Editor-in-Chief of the journal Chronobiologia from 1976–1994. He is the nominated expert in chronobiology for the Italian Ministry of Health. He has published widely. Email: [email protected]

Introduction The quantitative and qualitative characteristics of nocturnal sleep are important markers of quality of life that can positively or negatively affect individual 1 psycho-physical abilities . Physical activity is one of the lifestyle-related factors that is 2,3 crucial for the quality of sleep . In recent years, the relationship between sleep and physical activity has been the subject of numerous studies. Most of these studies show that regular physical exercise produces beneficial effects on nocturnal sleep, to the point that it is recommended 4,5 for patients with sleep disorders . In particular, in a comparative metaanalysis study on the effect that physical exercise can have on objective parameters 114

for sleep quality, it was found that physical activity can increase total sleep time and other parameters related to improving sleep quality, even though it did not induce significant modifications in terms of sleep 6 latency and night waking . Of particular relevance in the evaluation of the effect of exercise on sleep, is the time of day at which exercise is undertaken. In fact, the period between performing the physical activity and the start of nocturnal sleep is a relevant variable for determining the beneficial as opposed to the negative 6,7,8 . effects on the quality of sleep It is well-known that physical activity affects the body’s homeostasis by determining the biological effects that are the result of the interaction between the central nervous system, endocrine system and immune


Effects of endurance and strength exercise on sleep Available at URL: http://www.ismj.com 9

system respectively. The synchronising effect of physical activity is manifested by its ability to influence the biological rhythm of a variable, and moving the acrophase of the rhythm in relation to the time of the day when the physical activity was undertaken. It has also been shown that physical activity done at different times of the day can resynchronise the body’s rest-activity circadian rhythm. Studies that have evaluated physical activity in relation to circadian rhythms suggest that exercise can produce a shift in the circadian temporal structure. In particular, physical activity done regularly in the evening produces a shift in the phase of the rhythm of body temperature, heart rate and activity level with respect to the same activity carried out 8,10,11 . For this reason, in the morning evening exercise may have a negative effect on the beginning of nocturnal sleep. Important factors to consider are also related to the intrinsic characteristics of the 12,13,14,15 . type of physical activity practised In particular, the effects on sleep may be different for resistance-type exercise. The intensity of physical activity carried out in terms of maximal oxygen consumption (VO2max) for aerobic exercise, or of maximum load for strength exercise, could also be a determining factor for the quality 16 of sleep . It has been found that physical activities are not always able to determine changes in nocturnal sleep; particularly as in some studies it has been highlighted that these 12 activities have a positive effect on sleep , 17 while in other studies there was no effect on sleep. Another determining factor was the total duration of the physical activity; in fact, it has been shown that modification of nocturnal sleep may be observed only for physical activities that last for more than 6 one hour . The purpose of the present research was to 18,19,20 to evaluate use actigraph monitoring the effect of high-intensity endurance and strength exercises, both performed in the morning, on the quality of nighttime sleep.

Methods Study population and design Fifteen males (age: median 29, range 20-36 years; Body Mass Index (BMI 24.6, 20.7115

International SportMed Journal, Vol.12 No.3, 2011, pp. 113-124. 2

34.3 kg/m ) with an average level of training (for fitness/recreation) were recruited. They all participated in the study voluntarily, and gave their written informed consent. The protocol for the study was approved by the Institutional Review Board of the university. All the participants were physically active, training regularly (2-3 times a week) in gyms or attending fitness programmes. Preliminarily, at least one week before testing, maximal oxygen uptake (VO2max) and maximal upper limb strength (maximal weight load, WLmax) were assessed. To determine VO2max, the subjects underwent an incremental sub-maximal ergobike test, during which the oxygen uptake was measured by automatic metabolimeter (FitMate-Pro, Cosmed, Rome, Italy). The WL was directly calculated by an incremental single-lifting test on the horizontal bench (3min rest between repetitions). All of the participants were studied in three different testing sessions (baseline, endurance and strength) undertaken two weeks apart. The exercise sessions, endurance and strength, were performed in random order. The participants preliminarily completed a questionnaire covering their dietary habits, drug consumption, and use of alcohol and/or cigarettes. During the tests, the subjects did not modify their dietary habits and they also maintained regular sleep habits as verified for all the subjects by actigraph analysis. Baseline session After a two-week break from their usual physical activities, all the subjects were called to the laboratory on the same day and were subjected to rest-activity monitoring by actigraph (Actiwatch, Cambridge Neurotecnology, Cambridge, UK) non-stop for 48-hours (Epoch length 0,5min). Endurance session The endurance session started at 10h00 and was structured as follows: - aerobic exercise on the ergobike: 10min warm-up at 40% of VO2max; 30min workout at 80% of VO2max; 10min cool-down cycling at 50W; continuous monitoring by actigraph for 48-hours non-stop, starting immediately after the endurance session (Epoch length 0.5min).




Strength session The strength session started at 10h00 and was structured as follows: - strength exercise on the horizontal bench press: 10min warm-up + three sessions of specific warm-ups (weightfree, 20% and 40% of WLmax) + 4 maximal series (3-6reps to exhaustion) lifting the 80% of WLmax, 3min within the session; - continuous monitoring by actigraph for 48-hours non-stop, starting immediately after the strength session (Epoch length 0.5min). Moreover, they kept a daily diary on activities carried out during monitoring: bedtime, wake-up time and mealtimes. Actigraphy Activity analysis. In order to be sure that the subjects were not engaging in supplementary physical activities other than what was called for by the research protocol, an analysis of the level of activity (Actiwatch Activity Analysis Software, Cambridge Neurotechnology, Cambridge, UK) maintained in the periods between the end of the training sessions and the beginning of their nighttime sleep (activity level day 1) and during the daytime hours of the following day of the same session (activity level day 2), were carried out. Sleep analysis. The Actiwatch Sleep Analysis Software made it possible to calculate sleep-specific parameters from the activity-rest data. Analysis started with the onset of nocturnal rest (bedtime) and ended with the onset of daytime activity (wake time). Exact bedtimes and waking times were set for each subject using information from the rest-activity patterns and the diary. The following derived sleep parameters were considered: - Sleep Start. The start of sleep derived automatically using the Sleepwatch algorithm (expressed in hours and minutes). - Sleep End. The end of sleep derived automatically using the Sleepwatch algorithm (expressed in hours and minutes). - Assumed Sleep. The calculated difference in hours and minutes between the Sleep End and Sleep Start times. - Actual Sleep Time. The Assumed Sleep time minus the Sleepwatch 116

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algorithm determined Awake Time (time spent awake during the whole of the Assumed Sleep period). Sleep Efficiency. The percentage of time in bed actually spent sleeping. Sleep Latency. The period between bedtime and Sleep Start. Number of Sleep Bouts. The number of sleep episodes during the period between Sleep Start and Sleep End. Number of Immobile Phases. The number of epochs without movement during the period between Sleep Start and Sleep End. Number of Minutes Immobile. The total time spent without recording any movement within the period of Sleep Start and Sleep End. Movement and Fragmentation Index (MFI). The addition of the Movement Index (percentage time spent moving) and the Fragmentation Index (percentage of immobile phases of one minute). MFI is as an index of restlessness.

The baseline parameters of sleep represent the average of the two nights of monitoring, while for the two training sessions, the data were processed separately for the first (Night 1) and second night (Night 2) after training. Statistical analysis Statistical analysis was performed using Statistica 6.0 (Statsoft Inc., Tulsa, OK, USA). Data are expressed as mean ± SE. Sleep and Activity analysis was performed using Actiwatch Analysis Software. The differences in the sleep and activity parameters between the three experimental sessions (baseline, endurance and strength) were examined using the Student’s t-test. The value chosen for statistical significance was p