The purpose of the current study was to examine the effect of flavor on voluntary drinking and thermoregulatory responses in Chinese boys and girls exercising intermittently in a hot environment. Fourteen boys and girls (9 to 11 years old) performed four 3-hour intermittent exercise sessions (20-min walking sessions at 50% VO2peak followed by a 25-minute rest period) in a hot and humid environment (~30 °C ambient temperature and ~70% relative humidity). The participants consumed 1 of 4 beverages ad libitum in a randomized sequence by using a Latin-square principle: unflavored water (W), orange-flavored water (OF), lemon-flavored water (LF), and grape-flavored water (GF). No differences were observed in the total fluid intake (W vs. OF vs. LF vs. GF: Boys, 441 ± 114 vs. 493 ± 106 vs. 387 ± 83 vs. 568 ± 146 ml; Girls, 613 ± 131 vs. 923 ± 204 vs. 825 ± 157 vs. 790 ± 166 ml), urine and sweat output, and physiological perceptual variables among trials and between sexes. The results suggested that Chinese children can maintain body fluid balance while exercising moderately in a hot and humid environment by ad libitum drinking. The flavor of the beverages had no impact on the voluntary drinking and the state of hydration in the current study.
Stephen Heung-Sang Wong and Feng-Hua Sun
Stephen Heung-Sang Wong and Yajun Chen
This study examined the rehydration achieved by drinking different beverages during a short-term recovery period (REC) after exercise-induced dehydration.
Thirteen well-trained men (age 22.1 ± 3.3 yr, body mass 61.2 ± 9.1 kg, VO2max 64.9 ± 4.0 ml · kg−1 · min−1, maximum heart rate 198 ± 7 beats/min) ran for 60 min on 3 occasions on a level treadmill at 70% VO2max. All trials were performed in thermoneutral conditions (21 °C, 71% relative humidity) and were separated by at least 7 d. During 4 hr REC, the subjects consumed either a volume of a carbohydrate-electrolyte beverage (CE), lemon tea (LT), or distilled water (DW) equal to 150% of the body weight (BW) lost during the previous run. The fluid was consumed in 6 equal volumes at 30, 60, 90, 120, 150, and 180 min of REC.
After the completion of the 60-min run, the subjects lost ~2.0% of their preexercise BW in all trials, and no differences were observed in these BW changes between trials. At the end of REC, the greatest fraction of the retained drink occurred when the CE drink was consumed (CE vs. LT vs. DW: 52% ± 18% vs. 36% ± 15% vs. 30% ± 14%, p < .05). The CE drink also caused the least diuretic effect (CE vs. LT vs. DW: 638 ± 259 vs. 921 ± 323 vs. 915 ± 210 ml, p < .05) and produced the optimal restoration of plasma volume (CE vs. LT vs. DW: 11.2% ± 2.0% vs. –3.1% ± 1.8% vs. 0.2% ± 2.1%, p < .05).
The results of this study suggest that CE drinks are more effective than DW or LT in restoring fluid balance during short-term REC after exercise-induced dehydration.
Eric Tsz-Chun Poon, John O’Reilly, Sinead Sheridan, Michelle Mingjing Cai and Stephen Heung-Sang Wong
Weight-making practices, regularly engaged in by horse racing jockeys, have been suggested to impair both physiological and mental health. This study aimed to assess bone health markers, nutritional intake, bone-specific physical activity (PA) habits, and quality of life of professional jockeys in Hong Kong (n = 14), with gender-, age-, and body mass index-matched controls (n = 14). Anthropometric measurements, serum hormonal biomarkers, bone mineral density, bone-specific PA habits, nutritional intake, and quality of life were assessed in all participants. The jockey group displayed significantly lower bone mineral density at both calcanei than the control group (left: 0.50 ± 0.06 vs. 0.63 ± 0.07 g/cm2; right: 0.51 ± 0.07 vs. 0.64 ± 0.10 g/cm2, both ps < .01). Thirteen of the 14 jockeys (93%) showed either osteopenia or osteoporosis in at least one of their calcanei. No significant difference in bone mineral density was detected for either forearm between the groups. The current bone-specific PA questionnaire score was lower in the jockey group than the control group (5.61 ± 1.82 vs. 8.27 ± 2.91, p < .05). Daily energy intake was lower in the jockeys than the controls (1,360 ± 515 vs. 1,985 ± 1,046 kcal/day, p < .01). No significant group difference was found for micronutrient intake assessed by the bone-specific food frequency questionnaire, blood hormonal markers, and quality of life scores. Our results revealed suboptimal bone conditions at calcanei and insufficient energy intake and bone-loading PAs among professional jockeys in Hong Kong compared with healthy age-, gender-, and body mass index-matched controls. Further research is warranted to examine the effect of improved bone-loading PAs and nutritional habits on the musculoskeletal health of professional jockeys.
Wendy Yajun Huang, Stephen Heung-Sang Wong, Martin Chi-Sang Wong, Cindy Hui-Ping Sit, Raymond Kim-Wai Sum and Gang He
Hong Kong’s 2016 Report Card on Physical Activity (PA) for Children and Youth is the first evidence-based synthesis of various indicators related to individual behaviors that contribute to overall PA levels, settings and sources of influence, and strategies and investments in Hong Kong.
Following a standardized protocol, currently best available data for Hong Kong youth were collated and evaluated by an expert consensus panel on 9 indicators (5 activity behaviors and 4 influences on these behaviors).
Less than half of the children and youth met the recommended PA level. As a result, a D grade was given for Overall PA levels. Organized Sport Participation and Active Transportation received grades of C- and B, respectively. Sedentary Behaviors and School scored a C grade. Community and the Built Environment scored a grade of B. Family Influence received as low a score as Overall PA (D). Active Play and Government were not graded due to incomplete data.
PA levels are low and sedentary behaviors are high for children and youth in Hong Kong. Promising policies exist in schools and features of community and the built environment are favorable. Increasing family support should be emphasized for future PA promotion.
Yan Shi, Wendy Yajun Huang, Jane Jie Yu, Sinead Sheridan, Cindy Hui-Ping Sit and Stephen Heung-Sang Wong
Purpose: The aim of this study was to examine the factors that influence compliance and practical utility of a continuous wear protocols for activPAL™ among adolescents. Methods: Seven hundred and fifty-five (11–18 y; 50.6% girls) students wore the waterproof activPAL™ for 7 consecutive days. The effects of factors such as weather and practical strategies on compliance were assessed. Students were asked to note reasons for removing it in a log. After the 7-day period, students anonymously completed a practical utility questionnaire. Results: The final sample used to analyze compliance contained 588 available data points; 72.4% met the validity criteria, which were ≥4 valid days. Rainfall was inversely associated with total wear time, whereas using alcohol pads and cartoon stickers during the application were positively associated with total wear time. Sweating (25.2%) and skin irritation (39.0%) were the most reasons for 290 removal episodes by 235 students. The 131 questionnaires showed that 80.1% regarded the continuous wear period as too long and encountered problems, and 55% would rather not wear it again. Conclusion: Rainy weather affected girls’ compliance with the continuous wear protocol for activPAL™. Skin irritation and sweat-induced inadvertent drops caused removal. Future studies should investigate more user-friendly protocols.