Notes

The aim of this study was to compare the enjoyment levels of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) using the Exercise-induced Feeling Inventory (EFI) and Physical Activity Enjoyment Scale (PACES). The results showed a significant difference in enjoyment between the two exercise protocols, with participants reporting higher enjoyment levels during HIIT than MICT. However, there was no variation in EFI-Positive Engagement, Revitalization, Tranquillity, and PACES scores. This finding led to the acceptance of the null hypothesis.
Moreover, participants' rating of perceived exertion (RPE) and energy expenditure were higher during HIIT than MICT, indicating that HIIT required more physical consumption and caused more muscle fatigue. This is likely due to the release of stress hormones, such as epinephrine and cortisol, during HIIT. These hormones increase heart contraction, deliver blood and nutrients to body parts, and activate the oxidation of glucose in skeletal muscles. However, higher lactate levels resulted in increased acidity in the muscles, which could lead to fatigue and exhaustion.
The study also found that HIIT was associated with a greater release of pleasure hormones, such as dopamine, which contributed to participants' higher enjoyment levels during HIIT. However, HIIT's demanding nature could lead to more negative emotions, such as fatigue and exhaustion, which could decrease enjoyment levels to the same level as MICT. In contrast, MICT's lower intensity could lead to boredom and a lack of mental stimulation, resulting in higher EFI-Physical Exhaustion scores.
One limitation of this study is its short duration, which makes it difficult to predict the long-term effects of HIIT and MICT on enjoyment and exercise adherence. However, previous studies suggest that HIIT could be a more attractive and time-efficient training option, while MICT could promote the production of more mitochondria, which enhances lactic acid elimination and blood circulation during muscle exercise.
In conclusion, HIIT and MICT offer different benefits and drawbacks, and individuals should choose the exercise type that they enjoy and can adhere to based on their personal preferences and fitness goals. Nevertheless, HIIT may offer a more enjoyable and time-efficient option for those who struggle to engage in PA due to lack of time and enjoyment.