American Journal of Chinese Medicine
Heart rate responses and oxygen consumption during Tai Chi Chuan practice.
Author/s: Ching Lan
Abstract: Tai Chi Chuan (TCC) is a popular Chinese conditioning exercise, however, its exercise intensity remains controversial. The objective of this study was to determine the exercise intensity of Yang TCC by measuring heart rate (HR) responses and oxygen consumption (V[O.sub.2]) during practice. Fifteen men aged 39.9 [+ or -] 9.5 yrs (range 26-56 yrs) participated in this study. Subjects had practiced classical Yang TCC for 5.8 [+ or -] 2.4 years. HR responses and V[O.sub.2] were measured during practice of TCC by using a K4 telemetry system. Blood lactate was measured before and immediately after TCC practice. Additionally, breath-by-breath measurement of cardiorespiratory function and sequential determination of blood lactate were performed during the incremental exercise of leg cycling. Measurements obtained during the TCC practice and exercise testing were compared to determine the exercise intensity of TCC. While performing TCC, the mean HR of subjects was 140 [+ or -] 10 bpm, and the mean V[O.sub.2] was 21.4 [+ or -] 1.5 mL*[kg.sup.-1][min.sup.-1]. Compared with the data of the exercise test, the HR during practice was 58% of the heart rate range. Meanwhile, the V[O.sub.2] during TCC practice was 55% of the V[O.sub.2peak]. Additionally, the level of blood lactate immediately after TCC practice was 3.8 mM, which reflected the level of lactate during TCC, approximated the onset of blood lactate accumulation (OBLA). The results demonstrate that TCC is an exercise with moderate intensity, and is aerobic in nature.
Tai Chi Chuan, a branch of traditional Chinese martial arts, has been widely practiced since the 17th century. During its development, TCC gradually evolved into many styles. Among them the Chen’s style is the oldest, while the Yang’s style is the most popular. Classical TCC consists of many complex postures, and performing a complete set takes 20 to 30 minutes. In 1956, a simplified form of TCC was developed to facilitate promotion (China Sports, 1983). Simplified TCC consists of fewer postures and takes only five minutes to perform. Although simplified TCC is easier to learn, it may have lesser training benefits owing to the reduction of exercise intensity and duration.
Recent studies have shown that TCC can improve cardiorespiratory function (Lan et al., 1998; Lan et al., 1996; Lai et al., 1995), muscle strength (Lan et al., 1998) and balance (Tse et al., 1992; Wolf et al., 1997; Wolfson et al., 1996), as well as reducing blood pressure (Young et al., 1999) and the risk of falls (Wolf et al., 1996). Additionally, TCC can improve cardiorespiratory function in patients with coronary artery bypass grafting surgery (Lan et al., 1999). However, the exercise intensity of TCC remains controversial. Some studies only used several TCC postures for training (Wolf et al., 1996; Young et al., 1999), and the intensity and training effect might not be equal to a complete set of TCC. We believe that TCC-like calisthenics may have some benefits, but can not substitute for a complete set of TCC. From the perspective of exercise prescription, the intensity of standard TCC should be determined to facilitate the application of this exercise among different populations. To our knowledge, no study has continuously measured the HR responses and V[O.sub.2] of TCC. The purpose of this study was to determine the exercise intensity of the classical form of Yang TCC by simultaneously measuring the HR responses and V[O.sub.2] during the performance. Lactate response before and immediately after TCC practice was also measured.