Khon Kaen Qigong (KKQ) is a new type of exercise that combines Qigong (Baduanjin and Wuqinxi) with Muay Thai. No studies have demonstrated its effects on exercise intensity and cardiorespiratory responses. We aimed to investigate the intensity of the exercise using the cardiorespiratory responses in sedentary older adults. This was a randomized, controlled, pre-and post-test parallel-group study. The participants were randomly assigned to one of the two groups (n=30 each): the exercise or the control group. There were three phases (30 min each) for each activity, including before (baseline), during, and after (recovery) reading a book in the control group or performing KKQ in the exercise group. Heart rate and blood pressure were measured before, immediately after, and 30-min after the activities. Expired gas was collected to measure the respiratory responses and ventilatory efficiency throughout the experiment. Compared with reading, KKQ increased heart rate (p-value < 0.05) and respiratory responses and decreased ventilatory efficiency (All were p-value < 0.01). Markers indicating exercise intensity indicated very low-intensity exercises. This study suggests that a single bout of KKQ can be classified as a very light-intensity exercise according to very low increased cardiorespiratory responses in sedentary older participants. It also decreases ventilatory efficiency, which is related to cardiovascular risk factors. Further studies on KKQ training may confirm its impact on cardiovascular disease interventions.