The aim was to examine certain aspects of circulatory, metabolic, hormonal,

thermoregulatory, cognitive, and perceptual responses while sitting following a brief

session of high-intensity interval exercise. Twelve students (five men; age, 22

2 years) performed two trials involving either simply sitting for 180 min (SIT) or sitting for this same period with a 6-min session of high-intensity exercise after 60 min (SIT CHIIT).

At T0 (after 30 min of resting), T1 (after a 20-min breakfast), T2 (after sitting for 1 h),

T3 (immediately after the HIIT), T4, T5, T6, and T7 (30, 60, 90, and 120 min after

the HIIT), circulatory, metabolic, hormonal, thermoregulatory, cognitive, and perceptual

responses were assessed. The blood lactate concentration (at T3–T5), heart rate (at

T3–T6), oxygen uptake (at T3–T7), respiratory exchange ratio, and sensations of heat

(T3–T5), sweating (T3, T4) and odor (T3), as well as perception of vigor (T3–T6), were

higher and the respiratory exchange ratio (T4–T7) and mean body and skin temperatures

(T3) lower in the SITCHIIT than the SIT trial. Levels of blood glucose and salivary cortisol,

cerebral oxygenation, and feelings of anxiety/depression, fatigue or hostility, as well as

the variables of cognitive function assessed by the Stroop test did not differ between

SIT and SITCHIIT. In conclusion, interruption of prolonged sitting with a 6-min session

of HIIT induced more pronounced circulatory and metabolic responses and improved

certain aspects of perception, without affecting selected hormonal, thermoregulatory or

cognitive functions.