Kong Chuan Teh

Heart rate, oxygen uptake, and energy cost of ascending and descending the stairs

PURPOSE This study describes the heart rate and oxygen uptake responses during, and the intensity and caloric cost of, ascending and descending a public-access staircase. METHODS Subjects were initially assessed for their maximum oxygen uptake and heart rate on a treadmill in the laboratory. For field measurements, subjects ascended (N = 103) and descended (N = 49) 11 stories of 180 steps, each step of 15 cm in height, for a total vertical displacement of 27.0 m. RESULTS The mean oxygen uptake and heart rate during the last 30 s of ascending were 33.5 +/- 4.8 mL.kg(-1).min(-1) and 159 +/- 15 beats.min(-1), respectively. During the descent, oxygen uptake and heart rate during the last 30 s of the climb were 17.0 +/- 3.8 mL.kg(-1).min(-1) and 107 +/- 18 beats.min(-1), respectively. The estimated gross energy expended during ascending and descending were 19.7 and 9.0 kcal, or equivalent to an intensity of 9.6 and 4.9 metabolic equivalents (METs), respectively (or 10.2 and 5.2 kcal.min(-1), respectively). The caloric cost of stepping up and down a step was calculated to be 0.11 and 0.05 kcal, respectively. CONCLUSION Stair-climbing exercise using a local public-access staircase met the minimum requirements for cardiorespiratory benefits and can therefore be considered a viable exercise for most people and suitable for promotion of physical activity.

Conducting an Acute Intense Interval Exercise Session During the Ramadan Fasting Month: What Is the Optimal Time of the Day?

This study examines the effects of Ramadan fasting on performance during an intense exercise session performed at three different times of the day, i.e., 08:00, 18:00, and 21:00 h. The purpose was to determine the optimal time of the day to perform an acute high-intensity interval exercise during the Ramadan fasting month. After familiarization, nine trained athletes performed six 30-s Wingate anaerobic test (WAnT) cycle bouts followed by a time-to-exhaustion (Texh) cycle on six separate randomized and counterbalanced occasions. The three time-of-day nonfasting (control, CON) exercise sessions were performed before the Ramadan month, and the three corresponding time-of-day Ramadan fasting (RAM) exercise sessions were performed during the Ramadan month. Note that the 21:00 h session during Ramadan month was conducted in the nonfasted state after the breaking of the days fast. Total work (TW) completed during the six WAnT bouts was significantly lower during RAM compared to CON for the 08:00 and 18:00 h (p < .017; effect size [d] = .55 [small] and .39 [small], respectively) sessions, but not for the 21:00 h (p = .03, d = .18 [trivial]) session. The Texh cycle duration was significantly shorter during RAM than CON in the 18:00 (p < .017, d = .93 [moderate]) session, but not in the 08:00 (p = .03, d = .57 [small]) and 21:00 h (p = .96, d = .02 [trivial]) sessions. In conclusion, Ramadan fasting had a small to moderate, negative impact on quality of performance during an acute high-intensity exercise session, particularly during the period of the daytime fast. The optimal time to conduct an acute high-intensity exercise session during the Ramadan fasting month is in the evening, after the breaking of the days fast. (Author correspondence: abdul_rashid_aziz@ssc.gov.sg)