Kyung-Shin Park

Effects of Panax ginseng extract on lipid metabolism in humans

The purpose of this study was to examine the effects of Panax ginseng extract (PGE) on lipid metabolism in humans by measuring cholesterol, malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT). Serum total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL) and plasma MDA levels were decreased by administration of PGE for 8 weeks (6g per day), however, high density lipoprotein (HDL) was increased. Those results suggest that hypolipidemic effect of PGE is associated with a decrease in TC, TG, LDL, MDA levels and an increase in HDL. These findings support scientific claims that ginseng has the hypolipidemic potential. Administration of PGE increased SOD and CAT activities while decreased MDA level indicating that antioxidant potential of PGE might induce hypolipidemic effect as one of action mechanism.

Effects of high-intensity exercise training on body composition, abdominal fat loss, and cardiorespiratory fitness in middle-aged Korean females.

The primary purpose of this study was to investigate the effects of high-intensity exercise training under relatively equal energy expenditure on whole body fat and abdominal fat loss, and cardiorespiratory fitness. Twenty-two untrained middle-aged Korean females were randomized into one of the following groups: control, low-intensity training group (LI), and high-intensity training group (HI). Subjects completed 14 weeks of training at 50% maximal oxygen consumption (LI) or 70% maximal oxygen consumption (HI) with the volume of exercise equated relative to kilograms of body weight. Weekly exercise volumes were 13.5 METs⋅h/week for the first 4 weeks, 18 METs⋅h/week for next 5 weeks, and 22.5 METs⋅h/week for the final 5 weeks. Data were analyzed using 2-way repeated measures ANOVA with post hoc test, using Bonferronis correction. HI showed significant reductions in fat mass (p < 0.05), total abdominal fat (p < 0.01), and subcutaneous abdominal fat (p < 0.01). LI reduced total abdominal fat (p < 0.05), but there were no other significant changes found in the control or LI groups. Maximal oxygen consumption was enhanced in both HI and LI with no significant group difference. High-density lipoprotein cholesterol increased significantly in HI (p < 0.05). IL-6, C-reactive protein, TNF-α, and other blood lipids were unaltered following training. Results indicate that high-intensity exercise training is more beneficial in whole body and abdominal fat loss; however, cardiorespiratory enhancement shows a dose-response relationship with weekly exercise volume. It is suggested that 14 weeks of aerobic exercise training at either high- or low-intensity is not sufficient enough to induce changes in levels of inflammatory proteins.

Neither gender nor menstrual cycle phase influences exercise-induced lymphocyte apoptosis in untrained subjects

Lymphocyte apoptosis increases following maximal exercise. Estrogen hormones (E2) have been shown to protect lymphocytes from apoptosis in vitro, but it is unknown whether they can attenuate the apoptotic response to maximal exercise. The purpose of this study was to examine the effect of menstrual cycle variation on exercise-induced lymphocyte apoptosis in humans following exercise. Untrained healthy young men and regularly menstruating women not using hormonal contraceptives volunteered for the study. Women performed a maximal effort treadmill test for VO2 max once in the follicular phase (FOL) and once in the mid-luteal phase (ML) of their cycles. Men completed two VO2 max tests with periods of time between tests matched to those of the female subjects. Blood was collected before (PRE) and immediately after exercise (POST), and analyzed for apoptotic lymphocytes and estradiol. E2 concentrations in women were significantly greater during ML versus during FOL, both PRE and POST (p<0.0001). The percent of exercise-induced lymphocyte apoptosis was similar between women (23.2%+/-1.0%) and men (21.5%+/-0.4%). In women, the apoptotic response to maximal exercise was similar regardless of menstrual cycle phase (FOL=23.7%+/-0.9%, ML=22.7%+/-1.1%). Although elevated female sex hormones in vitro may exert anti-apoptotic effects, these data suggest that in vivo concentrations confer no protection to lymphocytes during exhaustive exercise.

Blood treatment influences the yield of apoptotic lymphocytes after maximal exercise.

PURPOSE No systematic investigation has been reported assessing the effect of cell isolation processes on postexercise apoptosis. Therefore, the effect of cell isolation procedures on apoptosis was evaluated in this study. METHODS Untrained healthy individuals participated (N=13). Blood samples obtained at rest and immediately after an incremental exercise test to exhaustion were partitioned into three treatments: 1) whole blood smears made immediately after the sample was obtained (WB), 2) cells subjected to density-gradient isolation before smears were made (ISO), and 3) samples allowed to sit at room temperature (i.e., time-treated) before centrifugation and smearing (TT). Blood smears were stained using the May-Grünwald Giemsa procedure and lymphocytes were evaluated under a light microscope for characteristic features of apoptosis. Data were analyzed using a 2x3 ANOVA. RESULTS A significant interaction effect existed (P<0.0001) such that at rest, no difference was detected in the amount of lymphocyte apoptosis among WB, ISO, or TT samples. However, after exhaustive exercise, the amount of apoptotic lymphocytes was significantly greater in WB compared with ISO and TT samples (P<0.0001). CONCLUSION Lymphocyte isolation results in a significant decrease in the percent of apoptotic lymphocytes after exhaustive exercise. This reduction is likely due to the time needed to isolate cells, rather than the isolation process itself. Because apoptosis is a time-sensitive process that occurs within minutes rather than hours, the length of time from initial sampling to the preparation of cells for assessment of apoptosis is critical and should be considered in future exercise studies.

Effects of summer school participation and psychosocial outcomes on changes in body composition and physical fitness during summer break

[Purpose] Evidence suggests that adolescents gain more weight during the summer break than they do during the school year, and that participation in the summer school program is beneficial in maintaining their healthy lifestyle. It is known that obesity and physical fitness in adolescents can be affected by their socio-economic and psychological status, especially during a long school break. The purpose of this study was to examine the effects of summer school participation and psychosocial outcomes on changes in body composition and physical fitness in underprivileged adolescents during the summer break. [Methods] Body composition and physical fitness in 138 underprivileged adolescents were measured at the beginning and end of the summer break. A survey on socio-economic and psychological status was conducted at the beginning of the summer break. Two-way repeated measures ANOVA and Tukey post hoc tests were used for data analysis. Pearson correlation analysis was performed to establish a relation between psychological outcomes and changes in body composition and physical fitness during the summer break. [Results] Significant increases in body weight (p = .003) and % body fat (p = .014) as well as a decrease in VO2max (p = .018) were found in summer school non-attendants during the summer whereas no significant changes were found in summer school attendants. Summer school non-attendants with lower psychosocial outcomes had a greater decline in physical fitness and weight gain; however, summer school attendants were not affected by psychosocial outcomes. The summer school program effectively prevented summer weight gain among underprivileged adolescents due to the structured environment, restricted food access, and scheduled time for exercise in addition to minimizing the effects of their psychosocial outcomes. [Conclusion] Results indicated that summer school non-attendants may require comprehensive intervention for psychosocial outcomes and nutritional education to maintain body weight and physical fitness levels during the summer break.

Responses of inflammatory cytokines following moderate intensity walking exercise in overweight or obese individuals

This study investigated the effects of a 4-week moderate intensity walking exercise on the levels of C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and adiponectin in overweight or obese individuals. Twenty-seven (13 men and 14 women) physically inactive, over-weight or obese (body mass index>25.0 kg/m2) individuals participated in the study. Each participant was randomly assigned to either exercise (EX; n=15) or control (CON; n=12) group. The EX group performed moderate intensity walking exercise on a treadmill for 60 min at 70% of maximal heart rate for 4 weeks (3 days/wk). Overnight fasting blood samples were collected before and after the study period (Pre and Post) to analyze the levels of pro-/anti-inflammatory cytokines such as CRP, TNF-α, and adiponectin. CRP and adiponectin as well as body weight and body composition were not significantly altered following the 4-week exercise intervention. However, there was a significant group×time interaction for TNF-α. The post hoc test revealed that the level of TNF-α significantly decreased only in EX (EX: mean±standard deviation, Pre 55.18±6.57 pg/mL, Post 50.31±6.22, P=0.018 vs. CON: Pre 55.5±5.88, Post 58.19±6.48, P=0.25). EX Post was also significantly lower as compared to CON Post (P=0.0074). Although there was no change in body weight or fat mass, the 4-week aerobic exercise training was long enough to decrease the level of TNF-α, indicating physical activity may improve level of inflammation independently from the change in fat mass. The current study also confirmed previous research suggesting that longer period of exercise training accompanied by weight loss may be required to induce significant changes in CRP and adiponectin.

Validity of Four-Compartment Model Body Fat In Physically Active Men And Women When Using DXA For Body Volume

The purpose of this study was twofold: 1) compare body volume (BV) estimated from dual energy X-ray absorptiometry (DXA) to BV from a criterion underwater weighing (UWW) with simultaneous residual lung volume (RLV), and 2) compare four-compartment (4C) model body fat percentage (BF%) values when deriving BV via DXA (4CDXA) and UWW (4CUWW) in physically active men and women. One hundred twenty-two adults (62 men and 60 women) who self-reported physical activity levels of at least 1,000 MET·min·wk-1 volunteered to participate (age = 22 ± 5 years). DXA BV was determined with the recent equation from Smith-Ryan et al. while criterion BV was determined from UWW with simultaneous RLV. The mean BV values for DXA were not significant compared with UWW in women (p = .80; constant error [CE] = 0.0L), but were significantly higher in the entire sample and men (both p < .05; CE = 0.3 and 0.7L, respectively). The mean BF% values for 4CDXA were not significant for women (p = .56; CE = -0.3%), but were significantly higher in the entire sample and men (both p < .05; CE = 0.9 and 2.0%, respectively). The standard error of estimate (SEE) ranged from 0.6-1.2L and 3.9-4.2% for BV and BF%, respectively, while the 95% limits of agreement (LOA) ranged from ±1.8-2.5L for BV and ±7.9-8.2% for BF%. 4CDXA can be used for determining group mean BF% in physically active men and women. However, due to the SEEs and 95% LOAs, the current study recommends using UWW with simultaneous RLV for BV in a criterion 4C model when high individual accuracy is desired.

Effects of unaccustomed downhill running on muscle damage, oxidative stress, and leukocyte apoptosis

[Purpose] The purpose of this study was to investigate the effect of unaccustomed downhill running on muscle damage, oxidative stress, and leukocyte apoptosis. [Methods] Thirteen moderately trained male subjects performed three 40 min treadmill runs at ~70% VO2max on separate days: a level run (L) followed by two downhill runs (DH1 and DH2). Blood samples were taken at rest (PRE) and immediately (POST), 2 h, 24 h, and 48 h after each run. Data were analyzed using 2-way repeated measures ANOVA with post hoc Tukey tests. [Results] Creatine kinase (CK) activity and oxidative stress level were significantly elevated at 24 h and 48 h following DH1 (P < 0.05). The level of oxidative stress at the POST measurement following DH1 and DH2 was greater than PRE. The rate of leukocyte apoptosis was significantly increased at the POST measurement following all three runs, and remained elevated for up to 48 h following DH1 (P < 0.01). [Conclusion] CK activity and oxidative stress were elevated following an acute bout of moderate intensity downhill running, resulting in a greater apoptotic response at 24 h and 48 h post-exercise in comparison with level grade running or a second downhill run. These elevations were blunted following DH2. Although the link between exercise-induced muscle damage and leukocyte apoptosis is currently unknown, the differential response to DH1 vs. L and DH2 indicates that it may be mediated by the elevation of oxidative stress.

Validity of BMI-Based Body Fat Equations in Men and Women: A 4-Compartment Model Comparison

Abstract Nickerson, BS, Esco, MR, Bishop, PA, Fedewa, MV, Snarr, RL, Kliszczewicz, BM, and Park, K-S. Validity of BMI-based body fat equations in men and women: a 4-compartment model comparison. J Strength Cond Res 32(1): 121–129, 2018—The purpose of this study was to compare body mass index (BMI)–based body fat percentage (BF%) equations and skinfolds with a 4-compartment (4C) model in men and women. One hundred thirty adults (63 women and 67 men) volunteered to participate (age = 23 ± 5 years). BMI was calculated as weight (kg) divided by height squared (m2). BF% was predicted with the BMI-based equations of Jackson et al. (BMIJA), Deurenberg et al. (BMIDE), Gallagher et al. (BMIGA), Zanovec et al. (BMIZA), Womersley and Durnin (BMIWO), and from 7-site skinfolds using the generalized skinfold equation of Jackson et al. (SF7JP). The 4C model BF% was the criterion and derived from underwater weighing for body volume, dual-energy X-ray absorptiometry for bone mineral content, and bioimpedance spectroscopy for total body water. The constant error (CE) was not significantly different for BMIZA compared with the 4C model (p = 0.74, CE = −0.2%). However, BMIJA, BMIDE, BMIGA, and BMIWO produced significantly higher mean values than the 4C model (all p < 0.001, CEs = 1.8–3.2%), whereas SF7JP was significantly lower (p < 0.001, CE = −4.8%). The standard error of estimate ranged from 3.4 (SF7JP) to 6.4% (BMIJA) while the total error varied from 6.0 (SF7JP) to 7.3% (BMIJA). The 95% limits of agreement were the smallest for SF7JP (±7.2%) and widest for BMIJA (±13.5%). Although the BMI-based equations produced similar group mean values as the 4C model, SF7JP produced the smallest individual errors. Therefore, SF7JP is recommended over the BMI-based equations, but practitioners should consider the associated CE.

Effects of Exercise Training on Fat Loss and Lean Mass Gain in Mexican-American and Korean Premenopausal Women

We investigated the effect of exercise training on body composition change in women. Nineteen Mexican-American and 18 Korean premenopausal overweight/obese women were randomized into one of the following groups: control, low-intensity training group (LI), and high-intensity training group (HI). Subjects completed 12 weeks of training at 50–56% maximal oxygen consumption (LI) or 65–70% maximal oxygen consumption (HI). Body composition components were measured at baseline and after training using dual-energy X-ray absorptiometry for Mexican-Americans, while whole-body composition was measured by the direct segmental multifrequency bioelectrical impedance analysis and abdominal fat was measured by single-slice computed tomography for Koreans. Data were analyzed using mixed-model repeated measures independent of age, ethnicity, and body mass index (BMI). Exercise training showed a significant effect on BMI, fat percentage, fat mass, lean mass, and visceral adipose tissue area. HI significantly decreased fat mass and fat percentage but increased lean mass (all P < 0.05). LI significantly reduced BMI, fat mass, fat percentage, and visceral adipose tissue area but increased lean mass (all P < 0.05). Exercise training had a beneficial effect on reducing BMI, fat percentage, fat mass, and visceral adipose tissue area but had no effect on increasing lean mass for Mexican-American and Korean premenopausal overweight/obese women.