The effect of a short-term ketogenic diet on exercise efficiency during graded exercise in healthy adults.

OBJECTIVE: We examined the effects of short-term KD on exercise efficiency and hormonal response during and after the graded exercise testing. METHODS: Fourteen untrained healthy adults (8 males, 6 females, age 26.4 ± 3.1 [SD] years; BMI 24.8 ± 4.6 kg/m2; peak VO2max 54.0 ± 5.8 ml/kg FFM/min) completed 3-days of a mixed diet (MD) followed by another 3-days of KD after 3-days of washout period. Upon completion of each diet arm, participants underwent graded exercise testing with low- (LIE; 40% of VO2max), moderate- (MIE; 55%), and high-intensity exercise (HIE; 70%). Exercise efficiency was calculated as work done (kcal/min)/energy expenditure (kcal/min). RESULTS: Fat oxidation during the recovery period was higher in KD vs. MD. Despite identical workload during HIE, participants after having KD vs. MD showed higher energy expenditure and lower exercise efficiency (10.1 ± 0.7 vs. 12.5 ± 0.3%, p < .01). After KD, free fatty acid (FFA) concentrations were higher during MIE and recovery vs. resting, and beta-hydroxybutylate (BOHB) was lower at HIE vs. resting. Cortisol concentrations after KD was higher during recovery vs. resting, with no significant changes during graded exercise testing after MD. CONCLUSIONS: Our data suggest that short-term KD is favorable to fat metabolism leading increased circulating FFA and BOHB during LIE to MIE. However, it is notable that KD may cause 1) exercise inefficiency manifested by increased energy expenditure and 2) elevated exercise stress during HIE and recovery. Trial registration: KCT0005172, International Clinical Trials Registry Platform.

Development of a New Submaximal Walk Test to Predict Maximal Oxygen Consumption in Healthy Adults.

The aim of the study was to develop a simple submaximal walk test protocol and equation using heart rate (HR) response variables to predict maximal oxygen consumption (VO2max). A total of 60 healthy adults were recruited to test the validity of 3 min walk tests (3MWT). VO2max and HR responses during the 3MWTs were measured. Multiple regression analysis was used to develop prediction equations. As a result, HR response variables including resting HR and HR during walking and recovery at two different cadences were significantly correlated with VO2max. The equations developed using multiple regression analyses were able to predict VO2max values (r = 0.75-0.84; r2 = 0.57-0.70; standard error of estimate (SEE) = 4.80-5.25 mL/kg/min). The equation that predicted VO2max the best was at the cadence of 120 steps per minute, which included sex; age; height; weight; body mass index; resting HR; HR at 1 min, 2 min and 3 min; HR recovery at 1 min and 2 min; and other HR variables calculated based on these measured HR variables (r = 0.84; r2 = 0.70; SEE = 4.80 mL/kg/min). In conclusion, the 3MWT developed in this study is a safe and practical submaximal exercise protocol for healthy adults to predict VO2max accurately, even compared to the well-established submaximal exercise protocols, and merits further investigation.

Physical activity and quality of life of patients with inflammatory bowel disease.

ABSTRACT: This study examined the association between physical activity (PA) and quality of life (QOL) in Korean patients with inflammatory bowel disease (IBD).We enrolled 158 patients with IBD (81 men and 47 women). PA levels were assessed using the International PA questionnaire. Using self-reported frequency (day) and duration (h) of physical activities, the patients were categorized into 3 groups based on their total metabolic equivalent (MET-h/wk) values: least, moderate, and most active. The QOL of patients with IBD was assessed using the inflammatory bowel disease questionnaire (IBDQ), the Medical Outcomes Study 36-Item Short Form Version 2 (SF36v2), the EuroQOL five dimensions questionnaire (EQ5D), and the EuroQOL visual analog scale (EQ-VAS).Of 158 patients, 62, 73, and 23 patients with Crohn disease, ulcerative colitis, and intestinal Behçet disease, respectively, were included. The mean age was 45.96 ±â€Š17.58 years, and 97 (61.4%) patients were men. Higher PA levels correlated with higher EQ5D and EQ-VAS scores (P < .001 and P = .004 respectively). In addition, depending on the type of PA, the amount of leisure activity was associated with higher IBDQ (κ = 0.212, P = .018), physical function of SF36v2 (κ = 0.197, P = .026), EQ5D (κ = 0.255, P = .002), and EQ-VAS (κ = 0.276, P = .001) scores. The frequency of sweat-inducing exercise showed an inverse correlation with IBDQ (κ = -0.228, P = .011), physical function of SF36v2 (κ = -0.245, P = .006), EQ5D (κ = -0.225, P = .007), and EQ-VAS (κ = -0.246, P = .004) scores.Increased PA levels were associated with improved QOL in patients with IBD. More leisure activity and non-sweat-inducing exercise were associated with improved QOL in patients with IBD.

Cardiopulmonary fitness but not muscular fitness associated with visceral adipose tissue mass.

PURPOSE: The purpose of this study is to identify the association between physical fitness (cardiopulmonary and musculoskeletal) and the distribution of abdominal fat in overweight and obese adults. METHODS: Of the total 102 overweight and obese participants, 99 participants completed all measurements. Cardiopulmonary fitness was assessed by maximal oxygen consumption test and muscular fitness was assessed using 10 repetition max. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were assessed by computed tomography (CT) at the level of lumbar spine 4-5. RESULTS: Cardiopulmonary fitness was inversely associated with both VAT and SAT, while muscular fitness only inversely associated with SAT. Multiple linear regression analyses indicated that gender, age, and cardiopulmonary fitness, but not muscular fitness, were associated with VAT, and age, cardiopulmonary fitness, and muscular fitness were significantly associated with SAT. CONCLUSIONS: Cardiopulmonary fitness is more closely related to both VAT and SAT while muscular fitness is related with SAT.

A new anthropometric index to predict percent body fat in young adults.

OBJECTIVE: To propose a new anthropometric index that can be employed to better predict percent body fat (PBF) among young adults and to compare with current anthropometric indices. DESIGN: Cross-sectional. SETTING: All measurements were taken in a controlled laboratory setting in Seoul (South Korea), between 1 December 2015 and 30 June 2016. PARTICIPANTS: Eighty-seven young adults (18-35 years) who underwent dual-energy x-ray absorptiometry (DXA) were used for analysis. Multiple regression analyses were conducted to develop a body fat index (BFI) using simple demographic and anthropometric information. Correlations of DXA measured PBF (DXA_PBF) with previously developed anthropometric indices and the BFI were analysed. Receiver operating characteristic curve analyses were conducted to compare the ability of anthropometric indices to identify obese individuals. RESULTS: BFI showed a strong correlation with DXA_PBF (r = 0·84), which was higher than the correlations of DXA_PBF with the traditional (waist circumference, r = 0·49; waist to height ratio, r = 0·68; BMI, r = 0·36) and alternate anthropometric indices (a body shape index, r = 0·47; body roundness index, r = 0·68; body adiposity index, r = 0·70). Moreover, the BFI showed higher accuracy at identifying obese individuals (area under the curve (AUC) = 0·91), compared with the other anthropometric indices (AUC = 0·71-0·86). CONCLUSIONS: The BFI can accurately predict DXA_PBF in young adults, using simple demographic and anthropometric information that are commonly available in research and clinical settings. However, larger representative studies are required to build on our findings.

Development of the Korean Global Physical Activity Questionnaire: reliability and validity study.

The goal of this study was to develop a Korean version of the Global Physical Activity Questionnaire (K-GPAQ) and to examine its reliability and validity. The English version of the GPAQ was translated to the Korean language (K-GPAQ) via forward-backward translation. Reliability of the K-GPAQ was evaluated using a one-week interval test-retest method with 115 individuals. Criterion-related validity of the K-GPAQ was examined with 199 participants using accelerometers. Cohen's kappa and Spearman's correlation coefficients were used to measure test-retest reliability and validity, respectively. A Bland-Altman analysis was used to assess agreement between physical activity (PA) levels measured via K-GPAQ and the accelerometer. Coefficients for the reliability of the K-GPAQ showed moderate agreement for recreational PA and slight agreement for work-related PA (Cohen's kappa: 0.60-0.67 for recreational PA and 0.30-0.38 for work-related PA and Spearman's rho: 0.27-0.47 for work-related PA and 0.53-0.70 for recreational PA). Criterion validity of the total amount of PA, as measured by the K-GPAQ and the accelerometer, showed a weak but significant correlation (r = 0.34, p < 0.01). The K-GPAQ is a reliable and valid questionnaire to measure PA although K-GPAQ overestimated PA levels.

Validation of Submaximal Step Tests and the 6-Min Walk Test for Predicting Maximal Oxygen Consumption in Young and Healthy Participants.

Background: This study aimed to test the validity of three different submaximal tests (i.e., 3-min step test with 20.3-cm step box height (3MST20), 3-min step test with 30-cm step box height (3MST30), and 6-min walk test (6MWT)) in estimating maximal oxygen consumption (VO2max) in young and healthy individuals. Methods: The 3MST20, 3MST30, 6MWT, as well as the cardiopulmonary exercise test (CPET) were performed in 73 participants (37 men and 36 women; mean age: 30.8 ± 9.3 years). All participants visited the clinic three times in a random order for anthropometric measurements, three submaximal tests, and the VO2max test. Multiple linear regression analyses were conducted to construct the VO2max prediction equations for each submaximal test. Results: The prediction equations developed based on multiple regression analyses for each submaximal tests were as follows: 3MST20: VO2max = 86.0 - 10.9 × sex (male = 1, female = 2) - 0.4 × age - 0.1 × weight - 0.1 × heart rate recovery at 30 s (HRR30s); 3MST30: VO2max = 84.5 - 10.2 × sex (male = 1, female = 2) - 0.4 × age - 0.1 × weight - 0.1 × HRR30s; and 6MWT: VO2max = 61.1 - 11.1 × sex (male = 1, female = 2) - 0.4 × age - 0.2 × weight - 0.2 × (distance walked·10-1). The estimated VO2max values based on formulated equations were 37.0 ± 7.9, 37.3 ± 7.6, and 36.9 ± 7.9 mL∙kg-1∙min-1 derived from the 3MST20, 3MST30, and 6MWT, respectively. These estimated VO2max values were not significantly different from the measured VO2max value, 37.3 mL∙kg-1∙min-1. The estimated VO2max based on the 3MST20, 3MST30, and 6MWT results explained 73.4%, 72.2%, and 74.4% of the variances in the measured VO2max (p < 0.001), respectively. Conclusions: The 3MST20, 3MST30, and 6MWT were valid in estimating VO2max in relatively young and healthy Asian individuals.

Dry Electrode-Based Body Fat Estimation System with Anthropometric Data for Use in a Wearable Device.

The bioelectrical impedance analysis (BIA) method is widely used to predict percent body fat (PBF). However, it requires four to eight electrodes, and it takes a few minutes to accurately obtain the measurement results. In this study, we propose a faster and more accurate method that utilizes a small dry electrode-based wearable device, which predicts whole-body impedance using only upper-body impedance values. Such a small electrode-based device typically needs a long measurement time due to increased parasitic resistance, and its accuracy varies by measurement posture. To minimize these variations, we designed a sensing system that only utilizes contact with the wrist and index fingers. The measurement time was also reduced to five seconds by an effective parameter calibration network. Finally, we implemented a deep neural network-based algorithm to predict the PBF value by the measurement of the upper-body impedance and lower-body anthropometric data as auxiliary input features. The experiments were performed with 163 amateur athletes who exercised regularly. The performance of the proposed system was compared with those of two commercial systems that were designed to measure body composition using either a whole-body or upper-body impedance value. The results showed that the correlation coefficient ( r 2 ) value was improved by about 9%, and the standard error of estimate (SEE) was reduced by 28%.

Effects of alternate day calorie restriction and exercise on cardio-metabolic risk factors in overweight and obese adults: an exploratory randomized controlled study.

BACKGROUND: It has been recognized that alternate day calorie restriction (ADCR) or exercise has positive effects on cardio-metabolic risk factors. It is unclear whether the combined effect of ADCR and exercise (aerobic + resistance training) influences risk. We investigated effects of an 8-week ADCR and exercise program (aerobic + resistance training) on cardio-metabolic risk factors in overweight and obese adults. METHODS: This study randomized 45 overweight or obese but healthy adults (F = 26, M = 19; aged about 32 to 40 years) into 4 groups: ADCR (n = 13), exercise (n = 10), exercise plus ADCR (n = 12), and control (n = 10) for 8 weeks. Body composition, blood lipids profile, and insulin resistance were measured. The intention to treat (ITT) method was used to analyze all participants that were randomized. RESULTS: A total of 35 participants completed the trial (78%). Body weight, body mass index, waist circumference, fat mass and percent body fat were reduced in the exercise plus ADCR group (- 3.3 ± 2.4 kg, p < 0.01; - 1.3 ± 1.0 kg/m2, p < 0.01; - 4.1 ± 3.9 cm, p < 0.01; - 2.7 ± 2.0 kg, p < 0.01; - 2. 5 ± 2.2%, p < 0.01). Insulin, glucose, homeostasis model assessment insulin resistance and triglyceride (- 2.9 ± 4.1 µIU/ml, p < 0.05; - 10.9 ± 16.9 mg/dl, p < 0.05; - 0.9 ± 1.3, p < 0.05; - 43.8 ± 41.9 mg/dl, p < 0.01) decreased in the exercise plus ADCR group only. CONCLUSIONS: ADCR and exercise both proved to be beneficial, but the combined intervention was most effective at inducing beneficial changes in body weight, body composition, glucose, insulin, insulin resistance and triglyceride in overweight and obese adults. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03652532 , Registered August 28, 2018, 'retrospectively registered'.

Effect of home-based exercise intervention on fasting insulin and Adipocytokines in colorectal cancer survivors: a randomized controlled trial.

BACKGROUND AND AIMS: Elevated circulating insulin is associated with increased risk of recurrence and cancer mortality in early-stage colorectal cancer (CRC). We conducted a randomized controlled trial to determine the effect of a 12-week home-based exercise program on fasting insulin, adipocytokines, and physical function in CRC survivors. METHODS: One hundred and twenty-three stage II-III CRC patients were randomly assigned to either a home-based exercise (n=62) or standard care control group (n=61) for 12weeks. Home-based exercise consisted of aerobic and resistance training, with a goal of obtaining ≥18 metabolic equivalent task (MET)-h/wk. Participants in the exercise group were instructed to participate in >18MET-h/wk. of aerobic and resistance exercise while the participants in the control group were asked to maintain their usual daily activity. The primary outcome was fasting insulin levels. Secondary outcomes were adiponectin, TNF-α levels and 6min walk distance from baseline to post-intervention. RESULTS: After the 12-weeks, moderate-vigorous physical activity participation increased from 9.1±14.7MET-h/wk. to 26.6±21.7MET-h/wk. in the exercise group, with no change in the control group (p<0.01 for group and time interaction). Circulating insulin level decreased by 1µU/ml (6.0±3.9 vs. 5.0±3.5, p=0.009) in the exercise group with no change in the control group (p=0.022 for group and time interaction). A similar trend was observed in TNF-α (p=0.030 for group and time interaction). Six minute walk distance increased by 25.2m in the exercise group with no change in the control group (p=0.061 for group and time interaction). CONCLUSIONS: The 12week home-based exercise program increased level of physical activity and decreased circulating insulin levels in CRC survivors.

Results From South Korea's 2016 Report Card on Physical Activity for Children and Youth.

BACKGROUND: South Korea's 2016 Report Card on Physical Activity for Children and Youth is the first assessment of physical activity according to the indicators set by Active Healthy Kids Global Alliance. METHODS: National surveys were used as preferred sources of data. This was then supported by peer-reviewed papers and government reports identified by a systematic search of the literature written in English or Korean. A Research Working Group then graded indicators based on the collected evidence. RESULTS: Each indicator was graded as follows: Overall Physical Activity, D-; Organized Sport and Physical Activity Participation, C-; Active Transport, C+; Sedentary Behavior, F; School, D; Government and Investment, C; Active Play, Physical Literacy, Family and Peers, and Community and Built Environment were graded INC (incomplete) due to lack of available evidence. CONCLUSIONS: Though the final grades of key indicators for South Korean children and youth are not satisfactory, increasing interests and investments have been demonstrated at a national level. More evidence is required for comprehensive assessment on all indicators to better inform policy and practice. This should be accompanied by the use of consistent criteria to contribute to global efforts for active healthy kids.

The association between resting heart rate and type 2 diabetes and hypertension in Korean adults.

OBJECTIVE: The purpose of this study was to analyse the association between resting heart rate (RHR) and type 2 diabetes and hypertension in Korean adults. METHODS: A total of 5124 participants, who participated in the exercise programme at the National Health Promotion Center between 2007 and 2010 (male=904, female=4220) were analysed in this study. Anthropometrics, body mass index (BMI), blood pressure (BP) and RHR were measured, and blood samples were collected after fasting for at least 12 hours. RESULTS: To investigate the association between RHR and metabolic parameters, participants were divided into quartiles. Participants in the fourth quartile (RHR >80 beats per minute (bpm) showed significantly higher systolic and diastolic BP and glucose compared with participants in the first quartile (RHR <69 bpm). When logistic regression analyses were performed, participants in the fourth quartile of RHR had 2.76 times (95% CI 2.03 to 3.77; absolute risk (AR): 12.1% (166/1371)) higher odds of type 2 diabetes and 1.27 times (95% CI 1.04 to 1.55; AR: 22.2% (304/1371)) higher odds of hypertension compared with those in the first quartile of RHR (type 2 diabetes AR: 5.3% (71/1346); hypertension AR: 18.9% (254/1346)). Multiple regression analyses showed that both BMI and RHR were significantly associated with glucose and mean arterial pressure. CONCLUSIONS: RHR is significantly associated with type 2 diabetes and hypertension independent of age, gender, BMI, smoking, drinking and family history of disease. RHR in combination with BMI, and multiple linear regression analyses emphasise the importance of the association of RHR with type 2 diabetes and hypertension in Korean adults.

Cardiopulmonary fitness, adiponectin, chemerin associated fasting insulin level in colorectal cancer patients.

PURPOSE: Since circulating level of insulin is associated with colorectal cancer prognosis, it is important to identify factors contributing to fasting insulin level in colorectal cancer patients. The purpose of the current study is to investigate the association of physical fitness, adiponectin, and chemerin levels with circulating level of insulin in colorectal cancer patients. METHODS: A total of 123 stage II-III colorectal cancer patients who completed standard cancer treatment were recruited. Anthropometric characteristics, fitness measurements, fasting insulin level, homeostasis model assessment of insulin resistance, lipid profiles, and adiponectin and chemerin levels were analyzed. RESULT: Cardiopulmonary fitness level inversely associated with fasting insulin levels (the least fit (1st tertile): 8.11 ± 0.64, moderately fit (2nd tertile): 6.02 ± 0.63, and highly fit (3rd tertile): 5.58 ± 0.66 µU/ml, unfit vs. moderately fit, p < 0.01; unfit vs. highly fit, p < 0.05) after adjustment for gender, age, stage, and BMI. In addition, fasting adiponectin and chemerin levels were associated with fasting insulin levels after adjustment for gender, age, stage, and BMI. In our combined analyses, participants with high adiponectin and low chemerin levels showed significantly lower fasting insulin levels (4.92 ± 0.75 vs. 8.07 ± 0.80 µU/ml, p < 0.01) compared with participants with low adiponectin and high chemerin levels. Multiple linear regression analysis confirmed that cardiopulmonary fitness and adiponectin levels (ß = -0.299, p = 0.002; ß = -0.201, p = 0.033) were independently associated with fasting insulin level. CONCLUSION: Our results suggest that physical fitness and adiponectin and chemerin levels may contribute to circulating levels of insulin. These results suggest that exercise may influence the prognosis of colorectal cancer patients by influencing physical fitness level, circulating levels of adiponectin and chemerin.

The association of resting heart rate with diabetes, hypertension, and metabolic syndrome in the Korean adult population: The fifth Korea National Health and Nutrition Examination Survey.

OBJECTIVE: Investigate the association of resting heart rate (RHR) with diabetes, hypertension and metabolic syndrome in a data set that represents the whole Korean adult population. METHODS: The data of 18,640 adults, that represent the whole Korean adult population, was used to examine the association of resting heart rate (RHR) with blood related variables, diabetes, hypertension and metabolic syndrome. RESULTS: Compared to participants with a RHR of <60 beats per minute (bpm), participants with a RHR of ≥90 bpm had higher odds of diabetes {3.85 [95% confidence interval (CI) 2.14-6.90], 3.34 (95% CI 1.83-6.10)} and metabolic syndrome [3.55 (95% CI 2.19-5.74), 2.15 (95% CI 1.37-3.35)], for men and women, respectively. Furthermore, compared to the participants with normal BMI (<23 kg/m(2)) normal RHR (<80 bpm), participants with high BMI (≥23 kg/m(2)) high RHR (≥80 bpm) had higher odds of diabetes [2.51 (95% CI 1.83-3.46), 4.89 (95% CI 3.63-6.58)], hypertension [3.88 (95% CI 3.00-5.01), 2.61 (95% CI 2.07-3.28)], and metabolic syndrome [9.67 (95% CI 7.42-12.61), 13.09 (95% CI 10.25-16.73)], for men and women, respectively. RHR shows a positive dose response relationship with the prevalence of diabetes and metabolic syndrome. The combined association of RHR with BMI increases the potency of RHR as a marker of diabetes, hypertension and metabolic syndrome. CONCLUSIONS: This study shows that RHR has an important role to play as a potential clinical measurement and prognostic marker.

Association between physical fitness, quality of life, and depression in stage II-III colorectal cancer survivors.

PURPOSE: The impact of cancer on quality of life and depression is an important issue. The purpose of this study was to identify the impact of physical fitness on quality of life and depression in stage II-III colorectal cancer survivors. METHODS: Participants in the current study included 122 stage II-III colorectal cancer survivors (57 females; 56.67 ± 9.16 years of age and 55 males; 54.69 ± 9.78 years of age). Fitness was assessed using the 6-min walk test, chair stand test, and push-up test. Quality of life and depression were measured using the Functional Assessment of Cancer Therapy-Colorectal (FACT-C) scale and a 9-item patient health questionnaire interview, respectively. RESULTS: There was a significant association between physical fitness and quality of life and depression in colorectal cancer survivors. The 6-min walk test results were associated with FACT-C total (r = 0.298, p < 0.05), physical well-being (r = 0.230, p < 0.05), functional well-being (r = 0.234, p < 0.05), colorectal cancer concern (r = 0.229, p < 0.05), and depression (r = -0.228, p < 0.05), and the chair stand test results were associated with functional well-being (r = 0.231, p < 0.05), colorectal cancer concern (r = 0.242, p < 0.05), and depression (r = -0.227, p < 0.05) even after controlling for all potentially confounding variables. A multiple regression analysis indicated that the 6-min walk was a significant predictor of health-related quality of life, and participants in the lowest tertile of the 6-min walk test results had lower quality of life and greater depression than those in the highest tertile. CONCLUSION: Improving and maintaining physical fitness are important for quality of life and depression in stage II-III colorectal cancer survivors.