عنوان مقاله [English]
The aim of this study was to investigate the effect of time of day (morning and evening) on the rate of fat oxidation and its changes trend in submaximal exercise in sedentary overweight girls. In this semi-experimental study, a practical approach was applied. 15 sedentary overweight female students (mean±SD age, height, weight, BMI and BF%: 23.3 ± 0.9 years, 162.6 ± 6.5 cm, 70.4 ± 4.5 kg, 26.6 ± 1.1 kg/m2 and 33.6 ± 2.2%) filled out a questionnaire and were randomly selected as the sample from eligible participants and divided into two groups: morning (n=7) and evening (n=8) with counterbalance method. The exercise protocol consisted of 60 min. of continuous running on a treadmill with %60 HRmax or about 56%VO2max performed in two sessions of 07:00 AM and 06:00 PM with a 7-day interval. VO2 and VCO2 were measured by gas analyzer system and the rate of fat oxidation per minute was calculated by Frayn stoichiometric equations. Paired t test and analysis of variance with repeated measures were used (P≤0.05). The results showed that the rate of fat oxidation and its changes trend in the evening was significantly higher than morning (P≤0.001). Finally, based on the results of this study, it appears that submaximal exercise in the evening has a higher effect on fat oxidation and helps weight loss.
1. خسروی، نیکو. سوری، رحمن. شاهقلیان، سمیه. (1390)." تأثیر زمان فعالیت در روز بر شاخصهای حداکثر اکسیداسیون چربی زنان سالم جوان" . مجله علوم زیستی ورزشی. ش11، ص 75-88.
2. رحمانی نیا، فرهاد. محبی، حمید. عزیزی، محمد. (1388)."تاثیر ریتم شبانه روزی بر پاسخ کورتیزول و انرژی مصرفی در مردان چاق و لاغر." فصل نامه المپیک. سال هفدهم. ش48، ص113-123.
3.غیاث, مجید. (2006)."بررسی تغییرات کورتیزول پلاسما در ورزشهای استقامتی". سیستم نشریات پزشکی ایران. 14(2), 36-41.
4. Ayko, S. Kellchi, M. (1995). "Circadian rhythm of Catecholamine excretion in rats after phase shift of light-dark Cycle". Ind Health. 33:57-66.
5. Bray,M.S. Young, M.E. (2006). "Circadian rhythms in the development of obesity: potential role for the circadian clock within the adipocyte".Obesity reviews, 8; PP:169-181.
6. Chwalibog, A. Thorbek, G. (2002). "energy expenditure and oxidation of carbohydrate and fat in humans during day and night". Thermochimica Acta; 394(1-2): 247.
7. Drust, B. (2005). "Circadian rhythms in sports performance". Chronobiology international 22.1 21-44.
8. Frayn, KN. (1983). "Calculation of substrate oxidation rates in vivo from gaseous exchange". J Appl Physiol. 55:628-634.
9. Froy, O. (2010). "Metabolism and Circadian Rhythms Implications for Obesity". Journal of Endocrine Society Endocrine Reviews 31: 1–24.
10. Goo, RH. Moore, JH. Greenberg, E. Alazraki, NP. ( 1987). "Circadian variation in gastric emptying of meals in man". Gastroenterology.; 93: 515-518.
11. Goldstein, David. (2007). "Time of day, intellectual performance, and behavioral problems in Morning versus Evening type adolescents: Is there a synchrony effect?." Personality and Individual Differences 42.3: 431-440.
12. James, P.T. Rigby, N. and Leach, R. (2004). "International Obesity Task Force The obesity epidemic, metabolic syndrome and future prevention strategies", Eur. J. Cardiovasc. Prev. Rehabil, 11, 38.
13. Khanfir, M. A. Bouaziz, W. Masmoudi, L. and Ben, H. (2013). "Effect of time-of-day specific obese training on body composition and physical capacity". Journal of Pharmacy and Biological Sciences, 2319-7676; PP 36-44.
14. Michelle C.Venables, Juul Achten, and Asker E. Jeukendrup. (2005)."Determinats of fat oxidation during exercise in healthy men and women". across sectional study”. J Apple Physiology 98;PP: 160.
15. Mohebbi, H. Azizi, M. Tabari, E. (2011). "Effect of time of day on MFO and Fatmax during exercise in obese and normal weight women". Series: Physical Education and Sport, Vol. 9, No 1, pages 69–79.
16. Reilly, T. Atkinson, G. Gregson, W. Drust, B. Forsyth, J. Edwards, B. Waterhous, J. (2006). “Some chronobiological consideration related to physical exercise”. Clinical Terapeutica. 157(3); PP:249-264.
17. Romijn, J.A. Coyle, E.F. Sidossis, L.S. Gastaldelli, A. Horowitz, F. Endert, E. & Wolfe, R.R. (1993). “Regulation of endogenous fat and carbohydrate metabolism in relation to exercise intensity and duration”. Am J Physiology Endocrinol Metab, 265; PP:E380-E391.
18. Saper, C.B. Lu, J. Chou and Gooley, J. (2005). "The hypothalamic integrator for circadian rhythms". Jornal of Trends Neurosciences , 28: 152-157.
19. Toyooka, J. Yoshikawa, K. (1995). “Substrate usage during prolonged exercise in the morning and evening”. Japanes Journal of Physical fitness and Sports Medicine, 44; PP:419-430
20. Uzu, T and Genjiro, K. (1999). "Diuretics shift circadian rhythm of blood pressure from nondipper to dipper in essential hypertension." Circulation 100.15 1635-1638.
21. Venut, T. (2003). “Best time of day to burn fat quikly”. Online ;www. Weightloss forall. com.
22. Vitaterna, M. H. Takahashi, J.S. Turek, F.W. (2001). "Overview of circadian rhytms, Jornal of Alchol research and health", 25 (2): 85-93.
23. Weinert, D. Waterhouse, J. (2007). "The circadian rhythm of core temperature: Effects of physical activity and aging", Physiology & Behavior.; 90:246–256.
24. Young, M.E. (2006). "The circadian clock within the heart: potential influence on myocardial gene expression, metabolism and function". American Journal of Physiology heart Circadian. Physiology.290: 1.