A Review by Alyssa Bialowas

HIIT (high intensity interval training) is a widely popular training method used in both endurance and sprint training. For endurance athletes, HIIT is beneficial in a number of ways, from increasing cardiovascular fitness to promoting healthy blood glucose levels and increasing endurance overall. For sprint athletes, the intense bursts of energy in HIIT benefit them in the sprint/power nature of their performance.

Due to endurance athletes’ training which encompasses metabolic and cardiorespiratory regulation and aerobic capacity, they excel in prolonged endurance events. On the flip side, sprint athletes have an advantage in high-intensity, short-term and explosive activities. But as this study by Cipryan et al. (2017) points out, what if exercise is described as a combination of high-intensity workload and prolonged duration?

Related Article: How HIIT Changes Our Body

The Study

There were sixteen participants in the present study, all of whom were highly trained male athletes participating in endurance or sprint sporting events. Each participant visited the lab four times over 1-2 weeks, always in the morning after a night of fasting. First, they performed a maximal incremental treadmill test, then a short HIIT (work interval duration 30s), long HIIT (3 min), and one constant load exercise session matched for mean load and total duration. They also completed a questionnaire about physical activity, acute chronic diseases and the use of dietary supplements.

After testing, the participants stayed in the laboratory for three hours for their recovery process to be assessed. Heart rate variation was measured before and after the exercise and 1 hour, 2 hours and 3 hours after the exercise intervention. Blood samples were also collected from the antecubital vein before and immediately after exercise, and 1 hour, and 3 hours after the exercise intervention.

The Results

The exercise interventions were matched for mean power, total time and work-to-relief ratio. Acute cardiorespiratory, metabolic variables, post-exercise changes in the heart rate variability, inflammation and muscle damage were monitored. Among the sixteen participants, it was found that endurance athletes performed exercise interventions with moderately or largely higher mean aerobic capacity. The other measurements did not indicate any considerable differences.


Although exercise intensity was identical for endurance and sprint athletes, endurance athletes performed both HIIT formats (short and long work intervals) with increased reliance on aerobic metabolic pathways compared to sprint athletes. Sprint athletes performed HIIT with moderately higher respiratory exchange ratio and moderately higher lactate values than endurance athletes. Acute respiratory and post-exercise autonomic and biochemical variables did not show any difference between endurance and sprint trained athletes.

Related Article: Clash Of The Titans – Intervals Vs Endurance (Part 1)

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Cipryan, L., Tschakert, G., and Hofmann, P. (2017). “Acute and Post-Exercise Physiological Responses to High-Intensity Interval Training in Endurance and Sprint Athletes.” Journal of Sports Science and Medicine, 16, 219-229.