Physiological Responses to Sprint Interval Exercise in a Fasted State in Active Men

Articles in Press

Document Type : Research Paper

Authors

Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, University of Guilan, Rasht, Iran

Abstract

Introduction: Fasting is a method used to enhance metabolic flexibility toward lipid utilization. However, there are concerns about hypoglycemia or protein breakdown in exercise. The present study investigated the physiological responses to sprint interval exercise with different rest durations in a fasting state. Methods: For this randomized crossover study, 10 healthy active men (aged 22.70 ± 1.15) were selected from eligible volunteers. In 2 separate sessions, following 14 hours of fasting, participants randomly performed 5×15s all-out sprints on an E894 MONARK ergometer with 30 or 60s rest intervals. Results: Diastolic blood pressure and heart rate were lower with longer rest intervals. Blood glucose, insulin, and urea remained unchanged after both protocols compared with baseline levels. There was a marked increase in lactate levels after both protocols, independent of the rest duration. The immune response was significantly higher with longer rest intervals than with short rest intervals or baseline levels. Conclusion: Sprint interval exercise performed in a fasted state did not induce hypoglycemia or evidence of protein degradation, suggesting that such training may be safe for active men. Longer rest intervals were associated with lower post-exercise heart rate and diastolic blood pressure, as well as an enhanced immune response. These findings suggest that coaches and practitioners may consider manipulating rest intervals to achieve targeted physiological adaptations.

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References

  1. Zouhal H, Saeidi A, Salhi A, Li H, Essop MF, Laher I, et al. Exercise training and fasting: current insights. Open access journal of sports medicine. 2020:1-28.
  2. Azizi F. Islamic fasting and health. Annals of nutrition and metabolism. 2010;56(4):273-82.
  3. Tang D, Tang Q, Huang W, Zhang Y, Tian Y, Fu X. Fasting: from physiology to pathology. Advanced Science. 2023;10(9):2204487.
  4. Rahim HA, Damirchi A, Babaei P. Comparison of HIIT and MICT and further detraining on metabolic syndrome and asprosin signaling pathway in metabolic syndrome model of rats. Scientific reports. 2024;14(1):11313.
  5. Sakhaei MH, Saidie P, Damirchi A. Effects of high-intensity interval versus moderate continuous exercise on plasma concentration of nitric oxide and level of blood pressure in inactive obese men. Journal of Applied Health Studies in Sport Physiology. 2024;11(1):11-22.
  6. Coates AM, Joyner MJ, Little JP, Jones AM, Gibala MJ. A perspective on high-intensity interval training for performance and health. Sports Medicine. 2023;53(Suppl 1):85-96.
  7. Kavaliauskas M, Aspe RR, Babraj J. High-intensity cycling training: the effect of work-to-rest intervals on running performance measures. The Journal of Strength & Conditioning Research. 2015;29(8):2229-36.
  8. Moghaddam M, Estrada CA, Muddle TW, Magrini MA, Jenkins ND, Jacobson BH. Similar anaerobic and aerobic adaptations after 2 high-intensity interval training configurations: 10: 5 s vs. 20: 10 s Work-to-Rest Ratio. The Journal of Strength & Conditioning Research. 2021;35(6):1685-92.
  9. Laursen PB, Jenkins DG. The scientific basis for high-intensity interval training. Sports medicine. 2002;32(1):53-73.
  10. Nicolò A, Bazzucchi I, Lenti M, Haxhi J, di Palumbo AS, Sacchetti M. Neuromuscular and metabolic responses to high-intensity intermittent cycling protocols with different work-to-rest ratios. International Journal of Sports Physiology and Performance. 2014;9(1):151-60.
  11. Stankevych L, Zemtsova I, Khmelnytska Y, Vdovenko N, Osipenko A, Krasnova S, et al. Correction of Endurance Training and Competitive Activities of Athletes by Determining the Blood Urea Content. Sport Mont. 2021;19.
  12. Jamurtas AZ, Fatouros IG, Deli CK, Georgakouli K, Poulios A, Draganidis D, et al. The effects of acute low-volume HIIT and aerobic exercise on leukocyte count and redox status. Journal of sports science & medicine. 2018;17(3):501.
  13. Schlagheck ML, Walzik D, Joisten N, Koliamitra C, Hardt L, Metcalfe AJ, et al. Cellular immune response to acute exercise: Comparison of endurance and resistance exercise. European journal of haematology. 2020;105(1):75-84.
  14. Templeton GF. A two-step approach for transforming continuous variables to normal: implications and recommendations for IS research. Communications of the association for information systems. 2011;28(1):4.
  15. Guo Z, Li M, Cai J, Gong W, Liu Y, Liu Z. Effect of high-intensity interval training vs. moderate-intensity continuous training on fat loss and cardiorespiratory fitness in the young and middle-aged a systematic review and meta-analysis. International Journal of Environmental Research and Public Health. 2023;20(6):4741.
  16. Tan V, Lim I, Tan PT, Tan F, Aziz AR. Comparison of physiological and clinical markers for chronic sprint-interval training exercise performed either in the fasted or fed states among healthy adults. Current research in physiology. 2021;4:192-201.
  17. Kriel Y, Askew CD, Solomon C. Sprint interval exercise versus continuous moderate intensity exercise: acute effects on tissue oxygenation, blood pressure and enjoyment in 18–30 year old inactive men. PeerJ. 2019;7:e7077.
  18. Batacan RB, Duncan MJ, Dalbo VJ, Tucker PS, Fenning AS. Effects of high-intensity interval training on cardiometabolic health: a systematic review and meta-analysis of intervention studies. British journal of sports medicine. 2017;51(6):494-503.
  19. Sant'Ana LdO, Scartoni FR, Martins da Cruz T, de Souza Ribeiro AA, dos Reis NR, Vieira da Silva JG, et al. Acute effects of different Sprint intervals on blood pressure, heart rate variability, lactate and performance responses in physically active men. The Open Sports Sciences Journal. 2022;15(1).
  20. Pesova P, Jiravska Godula B, Jiravsky O, Jelinek L, Sovova M, Moravcova K, et al. Exercise-induced blood pressure dynamics: insights from the general population and the athletic cohort. Journal of Cardiovascular Development and Disease. 2023;10(12):480.
  21. Carpio-Rivera E, Moncada-Jiménez J, Salazar-Rojas W, Solera-Herrera A. Acute effects of exercise on blood pressure: a meta-analytic investigation. Arquivos brasileiros de cardiologia. 2016;106:422-33.
  22. Al Attar AA, Fahed GI, Hoballah MM, Pedersen S, El-Yazbi AF, Nasser SA, et al. Mechanisms underlying the effects of caloric restriction on hypertension. Biochemical Pharmacology. 2022;200:115035.
  23. Tucker WJ, Sawyer BJ, Jarrett CL, Bhammar DM, Gaesser GA. Physiological responses to high-intensity interval exercise differing in interval duration. The Journal of Strength & Conditioning Research. 2015;29(12):3326-35.
  24. Schaun GZ, Del Vecchio FB. High-intensity interval exercises' acute impact on heart rate variability: Comparison between whole-body and cycle ergometer protocols. The Journal of Strength & Conditioning Research. 2018;32(1):223-9.
  25. Maughan R, Fallah J, Coyle E. The effects of fasting on metabolism and performance. British journal of sports medicine. 2010;44(7):490-4.
  26. Hinson J, Raven P, Chew S. 11 - INSULIN AND THE REGULATION OF PLASMA GLUCOSE. In: Hinson J, Raven P, Chew S, editors. The Endocrine System (Second Edition): Churchill Livingstone; 2010. p. 129-45.
  27. Jørgensen SW, Hjort L, Gillberg L, Justesen L, Madsbad S, Brøns C, et al. Impact of prolonged fasting on insulin secretion, insulin action, and hepatic versus whole body insulin secretion disposition indices in healthy young males. American Journal of Physiology-Endocrinology and Metabolism. 2021.
  28. Hejazi K, Toghdari A, Rahimzadeh Moghadam M, Fakhrealali M. The Effect of Ramadan Fasting Alone or in Conjunction with Physical Activity on Hematological Factors and Insulin Resistance in Adult Muslims: A Systematic Review and Meta-Analysis. Journal of Nutrition, Fasting and Health. 2025.
  29. Adams OP. The impact of brief high-intensity exercise on blood glucose levels. Diabetes, metabolic syndrome and obesity: targets and therapy. 2013:113-22.
  30. de Jesus ES, Aidar FJ, dos Santos IA, Brito CJ, dos Santos JL, Lima CA, et al. Do Different Interval Durations of High-Intensity Interval Training Influence Blood Glucose and Lactate, and Cause Hepatic Damage in Rats? JOURNAL OF BIOLOGICAL REGULATORS AND HOMEOSTATIC AGENTS. 2023;37(12):6637-42.
  31. Jacob N, So I, Sharma B, Marzolini S, Tartaglia MC, Green R. Effects of high-intensity interval training on blood lactate levels and cognition in healthy adults: protocol for systematic review and network meta-analyses. Systematic reviews. 2022;11(1):31.
  32. Kujach S, Olek RA, Byun K, Suwabe K, Sitek EJ, Ziemann E, et al. Acute sprint interval exercise increases both cognitive functions and peripheral neurotrophic factors in humans: the possible involvement of lactate. Frontiers in neuroscience. 2020;13:1455.
  33. Zhang Y, Chen P, Zhu X. Lymphocyte-to-white blood cell ratio is associated with outcome in patients with hepatitis B virus-related acute-on-chronic liver failure. World Journal of Gastroenterology. 2023;29(23):3678.
  34. Wahl P, Mathes S, Bloch W, Zimmer P. Acute impact of recovery on the restoration of cellular immunological homeostasis. International journal of sports medicine. 2020;41(01):12-20.
  35. Wang J, Liu S, Li G, Xiao J. Exercise regulates the immune system. Physical Exercise for Human Health. 2020:395-408.
Journal of Nutrition,Fasting and Health

Articles in Press, Accepted Manuscript
Available Online from 18 August 2025

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History

  • Receive Date: 10 June 2025
  • Revise Date: 11 August 2025
  • Accept Date: 17 August 2025

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