Rungchai Chaunchaiyakul

A Cross-sectional Study of Resting Cardio-respiratory and Metabolic Changes in Pregnant Women

[Purpose] We examined cardiorespiratory and metabolic changes across the 1st (G1), 2nd (G2) and 3rd (G3) trimesters in pregnant women. [Subjects and Methods] Forty-two healthy, active, non-smoking, pregnant women participated in this study. They were divided into G1, G2 and G3 groups depending on their mean gestational ages at the time of testing which were 10.5 ±2.9, 19.2 ±3.4, and 33.3 ±2.4 weeks of gestation, respectively. Cardio-respiratory and metabolic variables, VO2 (oxygen consumption), VCO2 (carbon dioxide production), and VE (minute ventilation), were measured using indirect calorimetry (IC, gas analyser) to estimate ventilatory equivalents of oxygen (VE/VO2) and carbon dioxide (VE/VCO2), RER (respiratory exchange ratio) and REE (resting energy expenditure). [Results] Women in the late pregnancy period had higher resting VCO2 and RER, whereas the VE/VCO2 ratio was significantly lower than in G1 and in G2. Even though the values of VO2 and REE increased throughout the course of pregnancy, no significant differences were found. [Conclusion] In pregnant women, resting cardiorespiratory and metabolic variables continuously changed throughout the 3 trimesters. Changes in VE/VCO2 and RER indicate shifting metabolic energy substrates. In addition, changes in cardiorespiratory variables, in parallel with gas exchange, indicate a better gas exchange process.

Lactose-free milk prolonged endurance capacity in lactose intolerant Asian males.

BackgroundSeveral studies on Caucasian volunteers have proven that milk is an effective recovery drink for athletes. Such benefit, however, cannot be directly applied to the lactose-intolerant Asian population. This study investigated the effects of ingesting water (WT), sports drink (SPD) and lactose-free milk (LFM) on cycling capacity.MethodsTen healthy young men completed 3 randomized experimental trials. Each trial consisted of an intermittent glycogen depleting session, a 2 h recovery period during which they ingested the test drink, followed by cycling at 70% of their maximum oxygen consumption (VO2max) to volitional exhaustion. Each trial was separated by at least one week.ResultsThere were no complaints or symptoms of lactose intolerance during any of the trials. The cycling periods were different (p < 0.05) amongst the 3 trials, namely, lactose-free milk (LFM; 69.6 ± 14.0 min), sports drink (SPD; 52.1!±11.6 min), and water (WT; 36.0±11.1 min), respectively. The VO2 and VCO2 of LFM (30±4 and 29±4 ml/kg/min) were lower (p < 0.05) than that of SPD (34±4 and 34±4 ml/kg/min) and WT (35±4 and 33±5 ml/kg/min). There were no differences (p = 0.45) in VO2 and VCO2 between SPD and WT. Mean rating of perceived exertion was lowest in LFM (14±5; p < 0.05), while no difference was found between the other two trials (SPD: 16±4 and WT: 16±4; p = 0.18).ConclusionLactose-free milk is likely to be an effective recovery drink for enhancing subsequent cycling capacity in lactose intolerant Asian males.

Deep ocean mineral supplementation enhances the cerebral hemodynamic response during exercise and decreases inflammation postexercise in men at two age levels.

Background: Previous studies have consistently shown that oral supplementation of deep ocean minerals (DOM) improves vascular function in animals and enhances muscle power output in exercising humans. Purpose: To examine the effects of DOM supplementation on the cerebral hemodynamic response during physical exertion in young and middle-aged men. Design: Double-blind placebo-controlled crossover studies were conducted in young (N = 12, aged 21.2 ± 0.4 years) and middle-aged men (N = 9, aged 46.8 ± 1.4 years). The counter-balanced trials of DOM and Placebo were separated by a 2-week washout period. DOM and Placebo were orally supplemented in drinks before, during, and after cycling exercise. DOM comprises desalinated minerals and trace elements from seawater collected ~618 m below the earths surface. Methods: Cerebral hemodynamic response (tissue hemoglobin) was measured during cycling at 75% VO2max using near infrared spectroscopy (NIRS). Results: Cycling time to exhaustion at 75% VO2max and the associated plasma lactate response were similar between the Placebo and DOM trials for both age groups. In contrast, DOM significantly elevated cerebral hemoglobin levels in young men and, to a greater extent, in middle-aged men compared with Placebo. An increased neutrophil to lymphocyte ratio (NLR) was observed in middle-aged men, 2 h after exhaustive cycling, but was attenuated by DOM. Conclusion: Our data suggest that minerals and trace elements from deep oceans possess great promise in developing supplements to increase the cerebral hemodynamic response against a physical challenge and during post-exercise recovery for middle-aged men.

Effect of Intake of Different Water Temperatures on Thermoregulatory Responses during Sauna Exposure

Drinking during heat exposure alters thermoregulatory responses of core and skin temperatures and compensatory mechanisms, including sweating. This study aims to investigate the effect of drinking water in different temperatures on core and skin temperatures and the amount of sweat under high heat stress in sauna. Nine healthy sedentary males were exposed to sauna room at 60-70°C for 30 min. After 10 min of acclimatization, intervention was randomly conducted, at least 1 week apart which asked subjects to drink water at 2% of nude body weights of 4 different temperatures: ambient temperature water (29.6 ± 0.2°C, AW group), cold water (4 ± 1°C, CW group), body temperature water (37 ± 1°C, BW group) and warm water (50 ± 1°C, WW group). Another trial of no water (NW group) supplement was conducted as control group. Skin temperatures (TS) and the amount of sweat at forehead (Tf, Sf), back (Tb, Sb), leg (Tl, Sl) and arm (Ta, Sa) were measured using digital thermistors connected to thermal sensor monitor (YSI Instruments Co., Yellow Spring, OH, USA) and wet-dry weights toweling method respectively. Rectal thermistor probe was used to monitor core temperature. Rectal temperature (Tr) in all groups changed in a narrow range from 36.41 to 36.93°C. There were different patterns of changes of Tr in all groups compared to initial values: steady throughout the study in AW group, gradually increased in BW group (at 25 and 30 min, P ＜ 0.05) and WW group (at 15, 25, and 30 min, P ＜ 0.05), and steeply declined in CW group (at 15, 25, and 30 min, P ＜ 0.05). After water intake, TS in all groups showed significant increase compared to corresponding initial values throughout the study (P ＜ 0.05). TS steeply changed at forehead, then slightly rose, and were finally steady throughout the rest of the study. In all skin areas, BW induced greater amounts of sweat (grams/min) than other groups did. The lowest amount of sweat was observed in CW group at all skin sites (P ＜ 0.05) throughout the study. The lowest amount of sweat was detected at forehead (P ＜ 0.05) and the highest one was detected at back region (Sb) (P ＜ 0.05) no matter which water temperatures had been consumed. Human body appropriately adjusted itself during 30 min of sauna exposure with narrow changes in core temperatures in all situations. Different water temperatures induced similar changes on skin at the selected sites. However forehead, which representd higher center, showed the highest increment in temperature. Compensation via sweating prevented a rise in core temperature and high amounts of sweat were observed at the limbs and trunk. We believed that vasomotor dilations via trunk and limbs are responsible for minimizing increase in higher center and core temperatures.