PURPOSE This study aimed to investigate the effects of continuous exercise and the accumulation of short-duration exercise for 12 weeks on body composition, physical fitness, and lifestyle disease indices in overweight men in their 30s. METHODS Participants in the continuous exercise group (CE; n=13) performed a circuit exercise program of 30 min/session, 3 sessions/week for 12 weeks. Participants in the accumulation of short duration exercise group (ASE; n=12) performed the same exercise time of 30 min per day, divided into three sessions of 10 min. Body composition, physical fitness, and lifestyle disease indices were measured pre- and post-test and were compared by utilizing a repeated two-way ANOVA. RESULTS 1) Regarding body composition, body weight, body mass index, skeletal muscle mass, waist circumference, and fat mass decreased significantly, while hip circumference increased significantly in the CE group. Waist circumference and skeletal muscle mass decreased significantly, while hip circumference increased significantly in the ASE group. 2) Regarding physical fitness, right grip strength, sit and reach, sit up, and maximal oxygen uptake increased significantly in both groups. 3) Regarding hypertension indices, there were no significant differences in both groups, but they showed a tendency to improve. 4) Regarding hyperlipidemia indices, triglycerides (TG) decreased significantly in both groups, and total cholesterol (TC) decreased significantly in the CE group. 5) Regarding diabetes indices, there were no significant differences in both groups, but a tendency to improve was noticed. 6) Regarding arteriosclerosis indices: TG/high density lipoprotein-cholesterol ratio decreased significantly in both groups, and the TC/high density lipoprotein-cholesterol ratio decreased significantly in the CE group. CONCLUSIONS We concluded that both the accumulation of short duration exercise and continuous exercise can be effective in improving body composition, physical fitness, and lifestyle disease in overweight men.
PURPOSE This study investigated the effects of moderate-intensity continuous exercise (MICE) and high-intensity interval exercise (HIIE), performed postprandially, on blood glucose, blood pressure, and blood lactate levels in men aged 40–50 with prediabetes and prehypertension. METHODS Twelve men with prediabetes and prehypertension were selected. After consuming a liquid meal, the participants participated in three trials: MICE, HIIE, and a non-exercise condition, with a one-week washout period between each trial. The trials were conducted in a counter-balanced manner to ensure equal energy expenditure across conditions. The intensity of the MICE trial was set at 70% of the heart rate reserve (HRR), whereas the HIIE trial alternated between 50% and 90% of HRR for 30 minutes. Blood glucose, blood pressure, and blood lactate levels were measured at various time points during each trial, and a two-way repeated-measures ANOVA was used for analysis. RESULTS 1) In the MICE trial, significant reductions were observed in blood glucose (at 15 and 30 minutes during exercise), systolic blood pressure (SBP) (at 50 minutes post-exercise), and diastolic blood pressure (DBP) (at 20, 40, 50, and 60 minutes post-exercise). 2) In the HIIE trial, significant reductions in blood glucose (at 15 and 30 minutes during exercise), SBP (at 40 minutes post-exercise), and DBP (at 40 minutes post-exercise) were observed. Blood lactate levels significantly increased. 3) When comparing the two exercise trials, blood glucose in the HIIE trials showed a recovery trend post-exercise, and blood lactate levels increased to a greater extent. CONCLUSIONS These findings suggest that both MICE and HIIE effectively lower blood glucose during exercise, but HIIE causes a more rapid post-exercise increase in blood glucose compared to MICE. In addition, MICE results in a smaller rise in blood lactate. Therefore, MICE is recommended for improving prediabetes and prehypertension. Future research should compare these effects in healthy individuals and examine long-term adaptations to repeated exercise.
Purpose The purpose of this study was to determine the effectiveness of six-weeks intermittent hypoxic training at 3,000 m hypobaric hypoxic condition on aerobic and anaerobic exercise capacity in competitive swimmers. Methods South Korean swimmers (n=20) were randomly assigned into training at sea-level (n=10, intermittent normoxic training group; INT) and training at 526 torr corresponding to 3,000 m hypobaric hypoxic condition (n=10, intermittent hypoxic training group; IHT). The participants completed an aerobic continuous treadmill training (30 min) within 80%HRmax and anaerobic interval bicycle training (10 times; 2 min of exercise and 1 min of rest) for 30min within 90%HRmax in each environment. We compared their aerobic and anaerobic exercise capacity before and after six-weeks of training. Exercise frequency was 1 hour, 3 days per a week, and during 6 week. Results In aerobic exercise capacity, PWC at 75%HRmax, estimated VO2 max, and exercise time were increased by training in only the IHT group. Estimated VO2 at 75%HRmax was increased by training in both groups, but presented a larger increase tendency in the IHT group compared with the INT group. In anaerobic exercise capacity, peak anaerobic power and fatigue index were increased by training in only the IHT group. Blood lactate level after wingate test were decreased by training in both groups, but the IHT group have a lower blood lactate level in after training compared with the INT group. Conclusion In our study, we did not measure to various dependent variables for support to enhancement of aerobic and anaerobic exercise performance. However, these results showed that the IHT method may be effective in improvement of exercise performance in competitive swimmers who participates in a variety of events from short to long distance.
PURPOSE Since the COVID-19 pandemic, the demand for home training, with exercises or workouts at home, has steadily increased. As a result, the popularity of home training YouTube content, which shows how to use exercise equipment or workouts without professional influence, has also increased. Therefore, this study focused on the characteristics of YouTube home training content (specialization, diversity, and interaction), personal health awareness, exercise awareness, and expectation-confirmation model to identify which required exercise continuation intention through YouTube home training. METHODS SPSS and AMOS software were used to conduct frequency, reliability, and confirmatory factor analyses, as well as to conduct correlation analysis and construct a structural equation model. RESULTS First, health and exercise awareness had a positive effect on confirmation. Second, among the characteristics of home training content, only specialization had a positive effect on perceived usefulness. Third, confirmation had a positive effect on perceived usefulness and viewing satisfaction, perceived usefulness had a positive effect on viewing satisfaction and exercise continuation intention, and viewing satisfaction had a positive effect on exercise continuation intention, which proved the expectation-confirmation model in this study. CONCLUSIONS To increase exercise continuation intention through home training YouTube content, creators need to produce professional content that can stimulate viewers' internal motivation.
Purpose The purpose of this study is to emphasize the need for the establish and the use of altitude training center via examining exercise training method in natural or artificial altitude environment that is applied to various elite athletes in various advanced countries to maximize exercise performance and its effectiveness. Results Altitude training in natural or artificial altitude environment enhances aerobic and anaerobic exercise performance baesd on the hematological and nonhematological adaptations to hypoxic conditions. These altitude training methods can be classified into living high training high (LHTH), living high training low (LHTL), and living low training high (LLTH). LHTH (i.e., developed since the 1968 Mexico Olympics) and LHTL (i.e., developed in the 1990s by Levine and Stray-Gundersen) improve exercise performance via hematologic changes through erythropoiesis such as increased hemoglobin mass and erythrocyte volume. On the other hand, LLTH (i.e., has been developed variously since the 2000s) is composed continuous hypoxic training (CHT), intermittent hypoxic training (IHT) and repeated sprint training in hypoxia (RSH), and the altitude environment is constructed using a vacuum pump and a nitrogen generator. In general, LLTH method dose not induce hematological change in a short time within 3 hours. However, CHT and IHT enhance aerobic exercise capacity by improved exercise economy, supply and utilization of blood to tissues, capillary and mitochondrial densities, and oxidative enzyme activity through various biochemical and structural changes in skeletal muscle and cardiac muscle. RSH enhances anaerobic power and repetitive sprint performance by improving glycolytic enzyme, glucose transport, and pH control. In Korea, however, there are almost no facilities for altitude training that is applied to enhance athletic performance in advanced sports countries and recognition of the need for altitude training is also very poor. Conclusions Therefore, it is very urgent to develop altitude training for maximizing athletic performance in Korea and a lot of support and efforts are needed from the government and local governments.
It has been reported that continuous exercise and bright light exposure improved resistance to stress and reduced depression and anxiety, which were attributed to enhancing neurotransmitter GABA exocytosis and stimulating neurogenesis. In this study, the effects of treadmill exercise and bright light exposure on the expression of GABAAreceptor activity, calcineurin and calcineurin calcium signaling pathway-depended NFATc4, neurogenesis-related protein Cdk5 and specific regulator factor of Cdk in neurogenesis p35 in the hippocampus of rats were investigated by western blot assay. The expression of GABAAreceptor, Cdk5 and p35 significantly increased in the exercise+light group compared to the control group and the light group. The expression of KCC2 and NFATc4 significantly increased in the exercise+light group compared to all the other groups. And the expression of calcineurin significantly increased in the exercise+light group compared to the control group. The overall results showed that exercise and bright light stimulated neurogenesis of the hippocampus in rats and had positive effects on improving the brain neuronal function.
Whether a nocturnal exercise with concomitant increase of body temperature (Tb) would intensify circadian phase delay compare to exercise with a suppressed Tb increase was examined. Seven healthy men (20.57 ± 2.88 yrs, 174.43 ± 4.05 cm, 70.13 ± 6.07 kg, 10.74 ± 1.92% fat) participated in two tests. Each lasted 5-days. On the day of 1 of each test, subjects maintained habitual sleep time (23:00-07:00, 0.2 lux) in laboratory. From day 2 thru 5, they biked for 60 min at 55% of maximal capacity beginning at 01:30 (15 lux). Then they went to bed at 04:00 and woke at 12:00. During test, they exercised either at 26℃ with elevating Tb (ET) or at 17℃ with cooling devices for suppressing Tb (ST). Two tests were counter balanced and separated by 2 weeks. During exercise, rectal (Tre) and skin (Tsk) temperatures, and heart rate were continuously recorded. Body weight changes during exercise were measured. Urine volume and saliva sample were collected. Blood samples were taken at 23:00, 03:30, 07:00, and 12:00 on day 1 and 5 of tests and analyzed for melatonin. The average weight loss for 4 days of exercise in ET and ST was 0.62 ± 0.09 and 0.22 ± 0.07 kg, respectively (p<.001). Tre increased during exercise but not different between conditions. Tsk maintained at 32℃ in ET and 24℃ in ST (p<.001). Tb were higher in ET than ST during exercise (p<.05). The average total urine volume passed was 0.07 ± 0.07 in ET and 0.11 ± 0.07 liter in ST (p<.05). The melatonin concentration at day 1 was 23 ± 26, 107 ± 45, 98 ± 46, and 14 ± 5 in ET and 18 ± 10, 108 ± 65, 103 ± 75, and 14 ± 12 pg/ml in ST for each time period. At day 5, it was 9 ± 3, 64 ± 41, 122 ± 73, and 54.1 ± 17.8 in ET and 8 ± 1, 68 ± 21, 111 ± 52, and 32 ± 14 pg/ml in ST. Differences of melatonin between ET and ST at day 5 of 12:00 as well as between day 1 and 5 at 12:00 of both conditions were noticed (p<.05). Salivary cortisol and immunoglobulin-A were not different. A nocturnal exercise induced a circadian phase delay in both conditions. However, body temperature increase during exercise intensified the shift indicating the importance of thermal load during exercise for circadian shift.
PURPOSE Blood pressure (BP) in hypertensive individuals is reduced by the accumulation of post-exercise hypotension (PEH) induced by a long period of training. This study aimed to investigate the effects of intensity of two different aerobic exercises with identical energy expenditure on post-exercise blood pressure and cardiovascular function in prehypertensive men. METHODS Eleven prehypertensive men in their 30s participated in two trials repeatedly. In the first trial, the exercise was moderate in intensity and continuous (MICE) with 70% of VO2max, and the exercise in the second trial was high-intensity interval exercise (HIIE) with 50% and 90% of VO2max. Each exercise was performed for 30 min, and the variables related to BP and cardiovascular function were measured at certain times for 1 hr during the recovery phase. RESULTS Our main findings are as follows: (1) Systolic blood pressure was significantly lower at 30 and 45 min of recovery time than the baseline in the HIIE trial, and systolic blood pressure was significantly lower in the HIIE trial than the MICE trial at 10, 15, and 30 min of recovery time. (2) The rate pressure product was significantly higher in the HIIE trial than the MICE trial at 15, 30, 45, and 60 min of recovery time. (3) The heart rate was significantly higher in the HIIE trial than the MICE trial at 15, 30, 45, and 60 min of recovery time. (4) Stroke volume was significantly lower in the HIIE trial than the MICE trial at 30 min of recovery time. (5) Cardiac output was significantly higher in the HIIE trial than the MICE trial at 15 min of recovery phase. (6) Total vascular conductance was significantly higher in the HIIE trial than the MICE trial at 15 and 30 min of recovery phase. (7) Total peripheral resistance was significantly lower in the HIIE trial than the MICE trial at 15 and 30 min of recovery phase. CONCLUSIONS The HIIE shows a higher cardiovascular stress than MICE; however, HIIE contributes to the augmentation of PEH and improvement of cardiovascular function. Therefore, HIIE rather than MICE should be suggested in BP control and enhancement of cardiovascular function in prehypertensive males.
The primary purpose of this study was to investigate the effects of 6 weeks of high-intensity intermittent training (HIIT) and moderate-intensity continuous training (MICT) under relatively equal energy expenditure on body composition, aerobic capacity, cardiovascular function, insulin resistance, and blood lipid profiles in 20s overweight males. Twenty-nine males were randomized into one of the following groups: HIIT group (n=11), MICT group (n=10), and control group(n=8). Subjects in HIIT group completed 6 weeks of training for 25 min/sessions, three times/wk, and subjects in MICT group exercised for 33 min/session to equalize the energy expenditure with HIIT group. Subjects in control group were asked to maintain their normal life pattern during the same intervention period. Data were analyzed using two-way repeated measures ANOVA with post hoc test. Main results of the present study were as follows: 1) Body weight, BMI, fat mass, and WHR decreased significantly in HIIT group. 2) VO2max, VEmax, and time to exhaustion increased significantly in HIT group. 3) SBP decreased significantly in HIIT group and HRrest was tended to decrease in HIIT. 4) Fasting plasma insulin and HOMA-IR were tended to decrease in HIIT, but the changes failed to reach the statistically significant level. 5) HDL-C and TG were tended to improve in HIIT, but the changes failed to reach the statistically significant level. Results indicate that high intensity intermittent exercise training is more beneficial in aerobic capacity and cardiovascular function. It was also suggested that 6 weeks of aerobic exercise training in either high intensity intermittent or moderate intensity continuous was not sufficient enough to induce changes in body composition, insulin resistance and blood lipid profiles.
Purpose The purpose of this study is to investigate the factors for setting proper training duration of frequency that can guarantee the student athletes' right to study and performance, and to derive the ranks of setting proper training duration of frequency of student athletes by school level. Consequently, to provide basic data for the development of training guidelines for the growth period of Korean student athletes. Methods Delphi and Analytic Hierarchical Process(AHP) techniques were used. The Delphi survey was conducted in three phases, and collected data through Delphi survey were computed by SPSS win ver. 22.0 and Excel, using the mean, standard deviation, median, and coefficient of variation. Using the AHP technique, we classified the factors for setting proper training duration of frequency derived through Delphi survey, and calculated the importance by using Microsoft Excel 2010. Conclusion First, elementary students should be guaranteed regular class participation, have basic after school training, and be provided with adequate rest so that they do not lose interest in the exercise. Second, middle school students are required to decide whether to continue exercise based on their ability to exercise and abundant experience. Therefore, when abandoning the exercise, students should be able to faithfully carry out their academic performance. Third, high school students are directly related to college entrance and employment, so they have to concentrate on performance rather than on academic performance.
