Abstract
nd: Maintaining physical performance during Ramadan Diurnal Fasting (RDF) is a challenge for professional athletes. The literature shows that sleep disturbances experienced by athletes during RDF are associated with reduced physical performance. The effect of sleep
Public Policies and Health, Beirut 03-690, Lebanon; nasser.abedelmajid@gmail.com (A.N.); ghaddarmohammad@gmail.com (M.G.) 7 Department of Biomedical Sciences, Lebanese International University, Beirut 03-690, Lebanon *Correspondence: ali.ghaddar@liu.edu.lb Abstract:Background: Maintaining physical performance during Ramadan Diurnal Fasting (RDF) is a challenge for professional athletes. The literature shows that sleep disturbances experienced by athletes during RDF are associated with reduced physical performance. The effect of sleep quality on physical performance, and the effect of work status on physical performance during RDF among athletes, besides engaging in trainings, have been little investigated. This study aims to evaluate the effect of RDF on the physical performance of professional athletes taking into consideration their sleep quality and work status. Methods: Professional medium-distance male runners (n = 32) participated in our study in the summer of 2019. Data about socio-demographics, training characteristics, sleep quality (Pittsburg Sleep Quality Index: PSQI), physical performance (Cooper Test; Harvard step test) were collected before and during Ramadan. Student’s-test and Welch and Wilcoxon tests were used for data analysis. Results: Both quality of sleep and physical performance of athletes deteriorated during Ramadan. People with better quality of sleep had better physical fitness/performance both before and during RDF. Athletes who worked beside trainings achieved worse physical fitness test results and had worse quality of sleep. Conclusions: Policies aimed to improve physical performance in RDF should consider the quality of sleep and the work status of athletes. Keywords:fasting; physical performance; Ramadan; sleep 1. Introduction Athletes who adhere to the Islamic code practice fasting for a whole month during the year, the month of Ramadan. During Ramadan diurnal fasting (RDF), athletes completely refrain from eating and drinking from sunrise to sunset and usually eat one meal after sunset “iftar” and another before sunrise “souhour”. The changes in meal timing during Ramadan produce a reduction in the frequency of food and water intake and an increase in the frequency of consumption of high calorie food and drinks (heavy meals) [1,2]. Ramadan fasting decreases glucose level and influences weight reduction, what can result in a lack of glycogen in the muscle and muscle protein degradation [1]. It also influences Circardian rhythms
during Ramadan produce a reduction in the frequency of food and water intake and an increase in the frequency of consumption of high calorie food and drinks (heavy meals) [1,2]. Ramadan fasting decreases glucose level and influences weight reduction, what can result in a lack of glycogen in the muscle and muscle protein degradation [1]. It also influences Circardian rhythms [3–5] and produces modifications in the sleep cycle and sleep patterns, with significant sleep alteration and sleep disturbances including delays in wake-up time and bedtime, increases in subjective and objective daytime sleepiness, and a reduction in Int. J. Environ. Res. Public Health2021,18, 6890.
Int. J. Environ. Res. Public Health2021,18, 6890 2 of 13 nocturnal sleep duration [6–10]. Moreover, it has been shown recently that RDF reduces total sleep time and increases excessive daytime sleepiness (Epworth sleepiness scale: ESS) [11]. Evidence about alternations in food intake and sleeping habits during RDF has led several researchers to explore the effect of RDF on athletes’ performance, though the evidence remains inconclusive. A recent systematic review concluded that RDF had no influence on the majority of physical performance parameters including strength, aerobic performance, jump height, fatigue and total work, though it negatively affected sprint performance [12]. In another study that controlled for food intake, sleeping time and training load, RDF appeared to reduce prolonged intermittent sprint performance in football players [13]. Zarrouk et al. concluded that RDF did not decrease neuromuscular performance, nor did it affect anthropometric parameters of athletes who engaged in RDF [14]. Similarly, other studies suggested that RDF had little or no effect on various performance tests among fasting athletes [15], and did not produce significant changes in physical performance in female athletes [16]. On the other hand, other research among football players suggested that RDF produces significant decrements in perceived and actual performance tests including speed, agility, dribbling speed, endurance [17], aerobic capacity and speed endurance performance [18]. Maughan & Shirreffs concluded that the dehydration associated with RDF could impair performance and recovery in competitions or events that last around one hour or more in athletes who engage in more than one event or training per day [19]. Similarly, it has been shown that dehydration in athletes increased heart rate and decreased ability to concentrate, reduced alertness and increased subjective sensations of fatigue [9]. While it has been clearly revealed that RDF increases the sensation of fatigue [20] and produces significant hormonal, metabolic, and inflammatory changes linked to sleep disturbances, changes in sleep patterns, reduction of hours of sleep, energy deficiency and fatigue in athletes [21], the topic has not yet been systematically evaluated. Further research is needed to deepen the understanding of sleep’s impact on performance [22]. Furthermore, the changes in the
the sensation of fatigue [20] and produces significant hormonal, metabolic, and inflammatory changes linked to sleep disturbances, changes in sleep patterns, reduction of hours of sleep, energy deficiency and fatigue in athletes [21], the topic has not yet been systematically evaluated. Further research is needed to deepen the understanding of sleep’s impact on performance [22]. Furthermore, the changes in the quality of sleep and its effect on athletes’ performance during RDF has been little investigated. In addition, the role of certain lifestyle-related variables, such as work status, that might influence physical performance of athletes during RDF has not been taken into consideration in previous research. We hypothesise that sleep quality decreases during RDF and reduces physical performance, and that athletes who have full-time job commitments besides engaging in trainings during RDF would have lower physical performance, independent on the quality of sleep. Therefore, the aim of the current study was to evaluate the effect of diurnal Ramadan fasting on the physical performance of professional athletes taking into consideration sleep quality and work status. 2. Material and Methods 2.1. Participants and Experimental Setting The study was conducted during Ramadan month, 2019, with a length of fasting day of approximately 15 h. The average temperature and humidity were around 30 ◦ C and 31% before Ramadan (BR) and 32 ◦ C and 34% during Ramadan (DR). Data were collected at two time intervals (two weeks before Ramadan and during Ramadan (third week)), in accordance with other similar studies [12]. Participants were thirty-two healthy male athletes aged 17–40 years performing endurance training in the form of running, who voluntarily participated in the study. Athletes who had experienced transmeridian travel were not included in the study. Participants were informed of details about the design of the study and the potential risks and benefits before providing their written informed consent. Participants were free to withdraw from the study at any time without further consequences. The study was approved by the Institutional Review Board of the Lebanese International University before the beginning of the assessments, approval Ref: LIUIRB–AG1).
of the study and the potential risks and benefits before providing their written informed consent. Participants were free to withdraw from the study at any time without further consequences. The study was approved by the Institutional Review Board of the Lebanese International University before the beginning of the assessments, approval Ref: LIUIRB–AG1).
Int. J. Environ. Res. Public Health2021,18, 6890 3 of 13 2.2. Study Design First, socio-demographic and training-related variables were collected using a self- made questionnaire. Then, in a prospective cohort design, data about sleep quality and physical performance were collected using The Pittsburg Sleep Quality Index (PSQI) and using the Cooper Test and the Harvard step test, respectively. All these measurements were repeated at two-time intervals, two-weeks before the start of Ramadan (baseline) and during 3rd week during Ramadan. 2.3. Data Collection 2.3.1. The Pittsburgh Sleep Quality Index (PSQI) The PSQI is self-report questionnaire and an effective instrument widely used by clini- cians and researchers to broadly assess several dimensions of sleep and assess the general quality of sleep in adults. It differentiates “poor” from “good” sleep quality by measuring seven areas (components): subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medications and daytime dysfunction over the last month. A total score of five or greater is indicative of poor sleep quality. The PSQI has been validated in numerous populations andlanguages [23,24] as well as many medical populations such as patients with insomnia, patients with traumatic brain injury, patients with cancer, patients receiving bone marrow and renal transplants, nursing home residents and pregnant women [25,26]. The Arabic version had been validated and has demonstrated acceptable reliability (Cronbach’s alpha coefficient = 0.77) [27]. 2.3.2. The Cooper Test The Cooper Test is a 12-min run test to determine aerobic fitness and provides an estimate of VO2max. The Cooper 12-min run test [28] requires the person being tested to run or walk as far as possible in a 12 min period. The objective of the test is to measure the maximum distance covered by the individual during the 12 min period and is usually carried out on a running truck by placing cones at various distances to enable measurement of the distance. The calculation of the estimated VO2 max results (in ml/kg/min) was performed according to the formula: VO2max = (22.351×kilometers)−11.288. There is a very high correlation between the distance ran (or walked) in 12 min
during the 12 min period and is usually carried out on a running truck by placing cones at various distances to enable measurement of the distance. The calculation of the estimated VO2 max results (in ml/kg/min) was performed according to the formula: VO2max = (22.351×kilometers)−11.288. There is a very high correlation between the distance ran (or walked) in 12 min and VO2 max value, which measures the efficiency of oxygen use while exercising. 2.3.3. The Harvard Step Test The Harvard step test is a type of cardiovascular endurance test that measures the efficiency of an athlete’s circulatory system and respiratory system in supplying oxygen to the working muscles and supporting sustained physical activity. It is also a good mea- surement of fitness and the ability to recover after strenuous exercise by checking the recovery rate (time needed for the heart rate to return to its normal rhythm). The test computes the capability of the individual to exercise continuously for extended intervals of time without tiring. Blood pressure was measured with a standardized upper arm cuff methodology using a “Reister” sphygmomanometer. After resting seated for 5 min, participants had three measurements taken from their left arm, with the average calcu- lated. If there was a difference of±5 mm Hg between the readings, researchers took an additional measurement. 2.4. Statistical Analysis Statistical analyses were performed using Statistical version 13.1 software (StatSoft). When the Shapiro-Wilk-test revealed that data were normally distributed, parametric tests were performed and the statistical analysis was performed by Student’s t-test. When data were not normally distributed, nonparametric tests were used. The statistical analysis was performed by the Welch test for dependent variables or the Wilcoxon test for independent variables. Significant differences were accepted for all tests withp< 0.05.
Int. J. Environ. Res. Public Health2021,18, 6890 4 of 13 3. Results 3.1. Characteristic of Participants The characteristics of the study participants are shown in Table. Participants were around 28±6.7 years old and had been practicing professional sports for around 10±5 years. Almost half were working full time (44%) and the rest were either working part-time or students (56%). The average training hours per week was 10.59±2.79 before Ramadan and 8.03±1.66 during Ramadan. Almost half trained twice per day (44%) before Ramadan while only 0.03% trained twice during Ramadan. Table 1.Anthropological and training characteristics of the study participants (n = 32). Age (years) 28.28 ±6.67 Body weight (kg) 69.58 ±8.18 Body height (cm) 174.59 ±7.01 Years in sport 10.19 ±4.94 Smoking (fraction of people) Manual work 0.44 Office work/ student 0.56 Working (fraction of people) Yes 0.53 No 0.47 Training characteristics before Ramadan No. training hours (hours/week) 10.59 ±2.79 No. trainings per day (fraction of people) Once a day 0.56 Twice a day 0.44 Training characteristics during Ramadan No. training hours (hours/week) 8.03 ±1.66 No. trainings per day (fraction of people) Once a day 0.97 Twice a day 0.03 3.2. Sleep Quality The PSQI results are presented in Table. In general, most of the athletes had low quality of sleep during both the period before Ramadan (BR) and during Ramadan (DR), although sleep quality decreased significantly DR (p< 0.001). The subjective sleep quality recorded DR was significantly poorer than that BR (p< 0.05). These results were consistent with those previously observed by Boukhris (2020) who also noticed a significant effect of Ramadan on sleep quality (p= 0.0006) (Table). In Herrera (2012) the values of subjective sleep quality recorded by PSQI were higher during Ramadan compared with those before Ramadan, but the differences were not statistically significant (Table). Compared to BR, a pair-wise comparison indicated that the sleep latency increased DR (p< 0.001) and daytime disfunctions intensified (p< 0.05). However, nonsignificant differences were noticed between the two time intervals for sleep duration, habitual sleep efficiency, sleep disturbances and use of sleeping medications (p> 0.05). A subanalysis of sleep quality changes among
the differences were not statistically significant (Table). Compared to BR, a pair-wise comparison indicated that the sleep latency increased DR (p< 0.001) and daytime disfunctions intensified (p< 0.05). However, nonsignificant differences were noticed between the two time intervals for sleep duration, habitual sleep efficiency, sleep disturbances and use of sleeping medications (p> 0.05). A subanalysis of sleep quality changes among poor sleepers vs. good sleepers (before Ramadan) also showed significant differences (p< 0.05), meaning that among athletes who had good sleep quality previously, deterioration in sleep quality was much more noticeable (Figure). Table 2.Subjective sleep quality (mean±SD) as estimated by the Pittsburgh Sleep Quality Index (PSQI). Values before (BR) and during (DR) Ramadan. BR DR Quality of sleep (Global PSQI score) (AU) 5.06 ±1.66 6.56±1.81 * Component 1: subjective sleep quality (AU) 0.97 ±0.74 1.59±0.91 * Component 2: sleep latency (AU) 0.81 ±0.54 1.09±0.59 * Component 3: sleep duration (AU) 1.03 ±1.09 1.03±1.09 Component 4: habitual sleep efficiency (AU) 0.0 0.0 Component 5: sleep disturbances (AU) 1.00 ±0.25 1.03±0.18 Component 6: use of sleeping medications (AU) 0.25 ±0.57 0.25±0.57 Component 7: daytime dysfunction over the last month (AU) 1.00±0.44 1.56±0.72 * *: Significant difference compared to BR. AU: arbitrary units.
Int. J. Environ. Res. Public Health2021,18, 6890 5 of 13 Table 3.Results of previous studies concerning the influence of Ramadan fasting on physical performance and quality of sleep. Subjects Measured Parameter Tests Main Results BR DR Conclusion Hsouna H. (2020) [29] 14 physically active males; 7 with 35-min nap (N35) and 7 without nap (N0) Sleep quality PSQI N0 3.86±0.47 N35 3.43±0.31 N0 4.50±0.45 N35 4.07±0.40 There was a significant increase in subjective sleep quality scores DR in comparison with BR. Boukhris O. (2019) [30] 14 physically active Arabic men Sleep quality PSQI 3.3 ±2.3 6.7 ±2.6 The sleep quality score was higher during Ramadan in comparison to before Ramadan. Herrera C. (2012) [10] 14 Muslim adult male football players Sleep quality PSQI 5.3 ±3 5.8 ±3 Although the differences were not statistically significant, the values during Ramadan were higher compared with before Ramadan. Güvenç A. (2011) [31] 16 soccer players Aerobic physical performance Shuttle Run Test RPE 14.75±1.48 RPE 16.00±1.75; 15.69±1.30 There was an increase in subjective ratings of perceived exertion at submaximal intensities during Ramadan. 70.24±10.56 HR at rest 68.59±9.14; 67.53±9.91 HR at rest 192.78±7.32 HR 193.49±7.97; 191.98±7.19 HR Miladi A. (2020) [32] 34 boys; 26 fasters and 10 non-fasters Cardiorespiratory capacity 6MWT F 680±76 NF 635±60 F 679±98 NF 619±69 RO did not impact the 6MWD HR value. F 78±7 HR at rest NF 79±6 HR at rest F 79±9 HR at rest NF 80±7 HR at rest F 122±14 HR response NF 118±13 HR response F 120±21 NF 118±18 Roy AS. (2015) [33] 77 young untrained Muslim men; 40 control group (CG) and 37 experimental group (EG) Aerobic physical performance Sumaximal test on ergometer (VO2max measurement) CG 43.73±5.13 mL/kg/min EG 44.02±5.24 mL/kg/min CG 44.96±4.84 mL/kg/min EG 39.23±4.41 mL/kg/min VO2max values in EG were significantly lower than those in CG during the month of Ramadan
Int. J. Environ. Res. Public Health2021,18, 6890 6 of 13Int. J. Environ. Res. Public Health 2021, 18, x FOR PEER REVIEW 7 of 15 F 122 ± 14 HR response NF 118 ± 13 HR response F 120 ± 21 NF 118 ± 18 Roy AS. (2015) [33] 77 young untrained Muslim men; 40 control group (CG) and 37 experimental group (EG) Aerobic physical performance Sumaximal test on ergometer (VO2max measurement ) CG 43.73 ± 5.13 mL/kg/min EG 44.02 ± 5.24 mL/kg/min CG 44.96 ± 4.84 mL/kg/min EG 39.23 ± 4.41 mL/kg/min VO2max values in EG were significantly lower than those in CG during the month of Ramadan bad good -6 -5 -4 -3 -2 -1 0 1 2 Changes in Quality of Sleep p<0.05 Figure 1. A subanalysis of sleep quality changes among poor sleepers vs. good sleepers (before Ramadan). 3.3. Fitness The results of fitness tests are presented in Table 4 and the changes in the results between BR and DR are presented in Tables 5-7. Generally, athletes obtained better phys- ical fitness results (Cooper Test and Step Test) BR than DR, with statistically significant differences (p < 0.05). Table 4. Physical performance (mean ± SD) as estimated by the Cooper test and Step test. Values before (BR) and during (DR) Ramadan. BR DR t p Cooper test Covered distance (meters) 3585.09 ± 332.65 3521.56 ± 327.70 2.39 8 0.023 VO2max. (mlO2/kg/min.) 68.86 ± 7.44 67.44 ± 7.33 2.39 8 0.023 Step test Heart rate at rest (per min) 71.16 ± 12.06 68.47 ± 9.81 3.44 1 0.001 POOR GOOD Figure 1.A subanalysis of sleep quality changes among poor sleepers vs. good sleepers (before Ramadan). 3.3. Fitness The results of fitness tests are presented in Table between BR and DR are presented in Tables–7. Generally, athletes obtained better physical fitness results (Cooper Test and Step Test) BR than DR, with statistically significant differences (p< 0.05). Table 4.Physical performance (mean±SD) as estimated by the Cooper test and Step test. Values before (BR) and during (DR) Ramadan. BR DR t p Cooper test Covered distance (meters) 3585.09±332.65 3521.56±327.70 2.398 0.023
Description
The study investigates how Ramadan fasting affects sleep quality and athletic performance.