The Influences of Physical Activity Amounts to Heart Rate Variability in Different Body Weight Groups Among Junior High School Pupils

• Main Authors: Yi-Hsun Lin, 林宜洵
• Other Authors: Yiing Mei Liou
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/96653675593565202859

碩士 === 國立陽明大學 === 社區護理研究所 === 95 === Background: The physical and psychological effect of overweight and obesity is profound and may bring society socioeconomic burden in obesity related health problems. In addition, obesity in adolescent is a crucial predictor of adult obesity. Physical activities could improve cardiopulmonary and cardiac autonomic functions. Much of literature proved the positive associations between parasympathetic never function and health indicators. Poor parasympathetic nerve function in obese people was also confirmed. However, it is not known if regular physical activity could reverse the effect of obesity. Thus, the purpose of this study is to investigate the effect of physical activity (PA) on heart rate variability (HRV) in junior high school students with various body weights. Purpose: The purpose of this study is to understand the influence of physical activity on sympathetic and parasympathetic function in normal weight group (NG) and overweight group (OG) junior high school students. Method: This is a cross-sectional relative study. The sample was recruited from 7th graders enrolled in four public junior high schools in Taipei or Kaohsiung cities. A total of 224 healthy 7th graders with normal weight and overweight participated in this study. Data on cardiac autonomic nerve function were collected with the non-invasion HRV meter (SS1C). Five minute of heart rate variability of each subject was recorded. Data was transmitted through frequency domain indicators including high and low frequency that reflecting autonomic nerve function. High frequency indicates parasympathetic activation while low frequency indicates both sympathetic and parasympathetic activation. The International Physical Activity Questionnaire (IAPQ) was used to measure the time the junior high school student spent in vigorous and moderate intensity physical activities, walking, physical education, after school activities, and being sedentary after school and weekends in the past 7 days. Results: The NG significantly spent more time on vigorous activity (not including walking), walking, moderate activity (including walking), and moderate activity per week than the OG. On the other hand, the OG spent more minutes per day on sedentary lifestyle after school including reading newspaper, magazines, comic books, or novels. In addition, the OG is significantly lower than the NG in meeting the physical activity recommendations including 150 minutes of moderate physical activity per week (MWPA), two hundred and ten minutes of MWPA per week, and 420 minutes of moderate to vigorous physical activity per week (MVPA). Compared with the NG, the OG had significantly reduced very low frequency power (VLF), low frequency power (LF), high frequency power (HF), and total power (TP). Body weight can explain 7.7% of low frequency power different between two groups. The body weight could explain 5.9% of LF after control of moderate activity (excluding walking) and moderate activity could explain 2.3% of LF. Subjects who met the physical activity recommendation of 420 minute of moderate activity per week had higher HF than those who did not despite of their body weight groups. Both OG who had 420 minute of MVPA per week and NG who did not have 420 minute of MVPA per week had similar HF. Conclusion: Body weight had lower effect on sympathetic and parasympathetic nerve function reflecting on LF after control of moderate PA excluding walking. The junior high school students who met the PA recommendation of 420 minute of MVPA per week had better improvement in HF, an indicator of health and reduced negative effects of obese on parasympathetic nerve function. In other words, physical activity could reduce the harmful effect of obese on health. Thus, to set up physical activity recommendation for adolescents is strongly suggested. Key word: obesity, autonomic nerve dysfunction, adolescent, physical activity, recommendation, International Physical Activity Questionnaire