1.Stress Accelerates Depressive-Like Behaviors through Increase of Notch2 Expression in N141I Mutation Presenilin-2 Transgenic Mice
Seung Sik YOO ; Sun Mi GU ; Kyung Tak NAM ; Jeong Soon CHOI ; Yong Sun LEE ; In Jun YEO ; Ji Eun YU ; Sanghyeon KIM ; Dong Won LEE ; Hyeon Joo HAM ; Ju Young CHANG ; Jaesuk YUN ; Dong Ju SON ; Sang-Bae HAN ; Jin Tae HONG
Biomolecules & Therapeutics 2026;34(3):544-555
Alzheimer’s disease (AD) is characterized by progressive cognitive deterioration and significant depression. However, the mechanisms linking depression to AD pathology remain unclear. Here, we investigated whether Notch2 signaling mediates depressionlike behaviors in presenilin-2 (PS2) N141I mutant mice, an early-onset AD model. PS2 wild-type (WT) and mutant (MT) mice aged 12-15 months were subjected to unpredictable chronic mild stress (UCMS) for 4 weeks, followed by sucrose preference, tail-hanging, and forced swimming tests. Behavioral assessments showed that UCMS exacerbated anhedonia and immobility only in PS2 MT mice. Molecular analysis revealed concomitant increases in plasma corticosterone, hippocampal γ-secretase activity, and Notch2 expression, and elevated total and phosphorylated glucocorticoid receptor levels in PS2 MT-UCMS mice. Gene expression profiling of human hippocampal datasets confirmed upregulation of NOTCH2 in Alzheimer’s disease and depression.Pharmacological inhibition of γ-secretase and Notch signaling with DAPT normalizes depressive behavior, reduces corticosterone release, attenuates GR phosphorylation, and inhibits Notch2 signaling in PS2 MT mice. These findings identify Notch2 as a pivotal mediator linking chronic stress to molecular changes associated with depression and AD, and suggest that targeting Notch2 signaling may provide therapeutic benefits for comorbid mood and neurodegenerative disorders.
2.Comparative Effects of Isometric Exercise Types on 24-Hour Ambulatory Blood Pressure in Young Men with Prehypertension: An Acute Pilot Trial
Seung Won JUNG ; Hyun Soo SONG ; Sun Jung KIM ; Ho Jeong MIN ; Tae Gu CHOI ; Hyun Jeong KIM ; Sae Young JAE
The Korean Journal of Sports Medicine 2026;44(1):25-33
Purpose:
This study aimed to compare the acute effects of isometric handgrip (IHG) and wall squat (IWS) exercise on 24-hour ambulatory blood pressure (BP) and related indices in young men with prehypertension.
Methods:
Ten young men with prehypertension (aged 25.0±2.3 years) completed three randomized crossover conditions: IHG, IWS, and control. Twenty-four-hour ambulatory BP monitoring was used to assess 24-hour, daytime, and nighttime mean BP, BP variability (BPV; average real variability and standard deviation), morning BP, and nocturnal dipping pattern. Office BP was measured at baseline, 30 minutes, and 90 minutes after each condition.
Results:
Twenty-four hour, daytime, and nighttime systolic and diastolic BP did not differ significantly among conditions. BPV indices also showed no significant between-condition differences across 24-hour, daytime, or nighttime periods. Nocturnal systolic BP dipping averaged 5%–8% and did not differ among conditions, indicating a nondipper pattern in all trials. Morning systolic BP, sleep-trough surge, and prewaking surge were similar across conditions. Office BP showed no significant condition or interaction effects; however, both IHG and IWS tended to lower BP at 90 minutes compared with control session.
Conclusion
A single bout of IHG or IWS did not elicit significant changes in 24-hour ambulatory BP, BPV, morning BP, or dipping pattern in young men with prehypertension. Nonetheless, the small acute reductions in office and morning BP suggest that isometric exercise may have potential as a time-efficient adjunctive strategy for early BP management. Larger and longer-term studies are needed to confirm these findings.
3.Acute Effects of Inspiratory Muscle Strength Exercise on Vascular Function and Shear Pattern in Young Adults
Tae Gu CHOI ; Hyun Soo SONG ; Sun Jung KIM ; Seung Won JUNG ; Byul KIM ; Hyun Jeong KIM ; Sae Young JAE
The Korean Journal of Sports Medicine 2026;44(1):16-24
Purpose:
Inspiratory muscle strength training is a time-efficient strategy for lowering blood pressure, but the acute vascular effects and its hemodynamic characteristics remain unclear. This study aimed to determine the acute effects of inspiratory muscle strength exercise (IMSE) on vascular function and shear patterns.
Methods:
In a single-arm acute trial, 12 young adults (aged 26±2 years) performed a single bout of IMSE (about 8 minutes) consisting of 30 breaths (6 breaths×5 sets) at 60% of maximal inspiratory pressure. Vascular function indices were assessed as endothelial function and arterial stiffness. Measurements of endothelial function via flow-mediated dilation (FMD) in the brachial artery and arterial stiffness by carotid-femoral pulse wave velocity (cfPWV) were taken at baseline, 10 minutes, and 40 minutes post-IMSE. Shear rate (SR) responses were continuously obtained throughout the IMSE session at the brachial artery and were analyzed as mean SR, anterograde SR, and retrograde SR.
Results:
Compared to baseline, cfPWV significantly decreased (7.95±0.9 m/sec to 7.49±0.9 m/sec, p=0.033) and FMD increased (4.76%±1.0% to 6.26%±1.1%, p< 0.001) at post-10 min. Both cfPWV and FMD returned to baseline levels at post-40 min. During IMSE, mean SR and anterograde SR significantly increased (both, p< 0.05), whereas retrograde SR decreased (p=0.032) during inter-set rest periods. In addition, rhythmic fluctuations in SR were observed corresponding to inspiration and expiration phases.
Conclusion
These findings suggest that an acute bout of IMSE is associated with improved endothelial function and arterial stiffness. IMSE may elicit distinct hemodynamic responses during exercise, which may be linked to improvements in vascular function.
4.Effects of Combined Exercise Training on Symptoms and Physical Fitness in Young Adults with Mild Long COVID
Tae Gu CHOI ; Jae Yeop KIM ; Ho Jeong MIN ; Hyun Jeong KIM ; Kanokwan BUNSAWAT ; Setor K KUNUTSOR ; Kevin S HEFFERNAN ; Sae Young JAE
The Korean Journal of Sports Medicine 2025;43(1):1-12
Purpose:
The aim of this study was to examine whether a combined exercise (EX), including aerobic, resistance, and inspiratory muscle training, reduces fatigue and dyspnea, improves physical fitness, and if increased physical fitness after exercise is associated with attenuating symptoms in young adults with mild long coronavirus disease (COVID) symptoms.
Methods:
Twenty-eight young adults (aged 23±4 years) with long COVID were randomly assigned to either the EX group (n=14), which underwent aerobic, resistance, and inspiratory muscle training three times per week for 8 weeks, or the control (CON) group (n=14). Symptoms of dyspnea and fatigue were assessed using self-report questionnaires.Cardiorespiratory fitness was directly measured during cardiopulmonary exercise testing, while muscle strength was measured by isokinetic muscle testing. These variables were measured before and after the exercise intervention.
Results:
Compared to the CON group, the EX group showed improvements in symptoms of fatigue and dyspnea, maximal oxygen consumption (VO2peak ), and peak torque, with significant interaction effects observed (p< 0.05). The EX group exhibited a mean difference of 2.9 mL/kg/min in VO2peak (95% confidence interval [CI], 1.8−4.0) and 13.0 Nm (95% CI, 6.1−19.8) in peak torque compared to the CON group (p<0.05). Improvements in VO2peak were negatively associated with attenuations in both fatigue and dyspnea after the exercise intervention (p<0.05).
Conclusion
These findings indicate that EX training can effectively alleviate symptoms and improve physical fitness in young adults with mild long COVID. Structured exercise training may serve as an effective intervention to improve the health of those with long COVID.
5.Do Strength and Anthropometric Size of the Lower Body Correlate with Serum Testosterone Levels?
Tae Yong PARK ; Moon Young CHOI ; Doohwan KONG ; Jeong Kyun YEO ; Min Gu PARK
The World Journal of Men's Health 2025;43(1):205-212
Purpose:
Although lower body strength and size are often regarded as symbols of masculinity, their relationship to testosterone is unclear. This study aimed to determine the correlation between lower body strength, size, and testosterone levels.
Materials and Methods:
Serum testosterone levels, waist circumference, and body mass index (BMI) were measured in 69 men with erectile dysfunction (age >40 years). The circumferences of the thigh and calf were measured, and the muscle strength of the knee joints was evaluated using an isokinetic dynamometer. Patients were classified into three groups according to testosterone levels (group 1, <230 ng/dL; group 2, 230 to 350 ng/dL; group 3, >350 ng/dL). Differences in calf and thigh circumference, bilateral knee extension, and flexion strength between the three groups were investigated using a one-way analysis of variance. Pearson’s chi-square test was used to assess differences in lifestyle habits and underlying diseases. A partial correlation analysis was conducted to determine the association between testosterone levels and lower body size and strength.
Results:
There was no difference in BMI among the three groups, but waist circumference was significantly larger in group 1 than in groups 2 and 3. When comparing weight-adjusted values, bilateral thigh circumference showed a significant difference among the three groups. There was also a significant difference between the three groups in the weight-adjusted left calf circumference and in the weight-adjusted right knee extension strength. The partial correlation test showed a significant positive correlation between thigh and calf circumference values adjusted for weight and serum testosterone levels. Weight-adjusted knee extension strength demonstrated a significant positive correlation with serum testosterone levels.
Conclusions
Weight-adjusted thigh and calf circumferences, along with the thigh-to-waist ratio, showed a positive correlation with testosterone levels. Weight-adjusted knee extension strength was positively correlated with testosterone levels. Therefore, a robust thigh and strong lower body are related to testosterone.
6.Effects of Combined Exercise Training on Symptoms and Physical Fitness in Young Adults with Mild Long COVID
Tae Gu CHOI ; Jae Yeop KIM ; Ho Jeong MIN ; Hyun Jeong KIM ; Kanokwan BUNSAWAT ; Setor K KUNUTSOR ; Kevin S HEFFERNAN ; Sae Young JAE
The Korean Journal of Sports Medicine 2025;43(1):1-12
Purpose:
The aim of this study was to examine whether a combined exercise (EX), including aerobic, resistance, and inspiratory muscle training, reduces fatigue and dyspnea, improves physical fitness, and if increased physical fitness after exercise is associated with attenuating symptoms in young adults with mild long coronavirus disease (COVID) symptoms.
Methods:
Twenty-eight young adults (aged 23±4 years) with long COVID were randomly assigned to either the EX group (n=14), which underwent aerobic, resistance, and inspiratory muscle training three times per week for 8 weeks, or the control (CON) group (n=14). Symptoms of dyspnea and fatigue were assessed using self-report questionnaires.Cardiorespiratory fitness was directly measured during cardiopulmonary exercise testing, while muscle strength was measured by isokinetic muscle testing. These variables were measured before and after the exercise intervention.
Results:
Compared to the CON group, the EX group showed improvements in symptoms of fatigue and dyspnea, maximal oxygen consumption (VO2peak ), and peak torque, with significant interaction effects observed (p< 0.05). The EX group exhibited a mean difference of 2.9 mL/kg/min in VO2peak (95% confidence interval [CI], 1.8−4.0) and 13.0 Nm (95% CI, 6.1−19.8) in peak torque compared to the CON group (p<0.05). Improvements in VO2peak were negatively associated with attenuations in both fatigue and dyspnea after the exercise intervention (p<0.05).
Conclusion
These findings indicate that EX training can effectively alleviate symptoms and improve physical fitness in young adults with mild long COVID. Structured exercise training may serve as an effective intervention to improve the health of those with long COVID.
7.Do Strength and Anthropometric Size of the Lower Body Correlate with Serum Testosterone Levels?
Tae Yong PARK ; Moon Young CHOI ; Doohwan KONG ; Jeong Kyun YEO ; Min Gu PARK
The World Journal of Men's Health 2025;43(1):205-212
Purpose:
Although lower body strength and size are often regarded as symbols of masculinity, their relationship to testosterone is unclear. This study aimed to determine the correlation between lower body strength, size, and testosterone levels.
Materials and Methods:
Serum testosterone levels, waist circumference, and body mass index (BMI) were measured in 69 men with erectile dysfunction (age >40 years). The circumferences of the thigh and calf were measured, and the muscle strength of the knee joints was evaluated using an isokinetic dynamometer. Patients were classified into three groups according to testosterone levels (group 1, <230 ng/dL; group 2, 230 to 350 ng/dL; group 3, >350 ng/dL). Differences in calf and thigh circumference, bilateral knee extension, and flexion strength between the three groups were investigated using a one-way analysis of variance. Pearson’s chi-square test was used to assess differences in lifestyle habits and underlying diseases. A partial correlation analysis was conducted to determine the association between testosterone levels and lower body size and strength.
Results:
There was no difference in BMI among the three groups, but waist circumference was significantly larger in group 1 than in groups 2 and 3. When comparing weight-adjusted values, bilateral thigh circumference showed a significant difference among the three groups. There was also a significant difference between the three groups in the weight-adjusted left calf circumference and in the weight-adjusted right knee extension strength. The partial correlation test showed a significant positive correlation between thigh and calf circumference values adjusted for weight and serum testosterone levels. Weight-adjusted knee extension strength demonstrated a significant positive correlation with serum testosterone levels.
Conclusions
Weight-adjusted thigh and calf circumferences, along with the thigh-to-waist ratio, showed a positive correlation with testosterone levels. Weight-adjusted knee extension strength was positively correlated with testosterone levels. Therefore, a robust thigh and strong lower body are related to testosterone.
8.Effects of Combined Exercise Training on Symptoms and Physical Fitness in Young Adults with Mild Long COVID
Tae Gu CHOI ; Jae Yeop KIM ; Ho Jeong MIN ; Hyun Jeong KIM ; Kanokwan BUNSAWAT ; Setor K KUNUTSOR ; Kevin S HEFFERNAN ; Sae Young JAE
The Korean Journal of Sports Medicine 2025;43(1):1-12
Purpose:
The aim of this study was to examine whether a combined exercise (EX), including aerobic, resistance, and inspiratory muscle training, reduces fatigue and dyspnea, improves physical fitness, and if increased physical fitness after exercise is associated with attenuating symptoms in young adults with mild long coronavirus disease (COVID) symptoms.
Methods:
Twenty-eight young adults (aged 23±4 years) with long COVID were randomly assigned to either the EX group (n=14), which underwent aerobic, resistance, and inspiratory muscle training three times per week for 8 weeks, or the control (CON) group (n=14). Symptoms of dyspnea and fatigue were assessed using self-report questionnaires.Cardiorespiratory fitness was directly measured during cardiopulmonary exercise testing, while muscle strength was measured by isokinetic muscle testing. These variables were measured before and after the exercise intervention.
Results:
Compared to the CON group, the EX group showed improvements in symptoms of fatigue and dyspnea, maximal oxygen consumption (VO2peak ), and peak torque, with significant interaction effects observed (p< 0.05). The EX group exhibited a mean difference of 2.9 mL/kg/min in VO2peak (95% confidence interval [CI], 1.8−4.0) and 13.0 Nm (95% CI, 6.1−19.8) in peak torque compared to the CON group (p<0.05). Improvements in VO2peak were negatively associated with attenuations in both fatigue and dyspnea after the exercise intervention (p<0.05).
Conclusion
These findings indicate that EX training can effectively alleviate symptoms and improve physical fitness in young adults with mild long COVID. Structured exercise training may serve as an effective intervention to improve the health of those with long COVID.
9.Do Strength and Anthropometric Size of the Lower Body Correlate with Serum Testosterone Levels?
Tae Yong PARK ; Moon Young CHOI ; Doohwan KONG ; Jeong Kyun YEO ; Min Gu PARK
The World Journal of Men's Health 2025;43(1):205-212
Purpose:
Although lower body strength and size are often regarded as symbols of masculinity, their relationship to testosterone is unclear. This study aimed to determine the correlation between lower body strength, size, and testosterone levels.
Materials and Methods:
Serum testosterone levels, waist circumference, and body mass index (BMI) were measured in 69 men with erectile dysfunction (age >40 years). The circumferences of the thigh and calf were measured, and the muscle strength of the knee joints was evaluated using an isokinetic dynamometer. Patients were classified into three groups according to testosterone levels (group 1, <230 ng/dL; group 2, 230 to 350 ng/dL; group 3, >350 ng/dL). Differences in calf and thigh circumference, bilateral knee extension, and flexion strength between the three groups were investigated using a one-way analysis of variance. Pearson’s chi-square test was used to assess differences in lifestyle habits and underlying diseases. A partial correlation analysis was conducted to determine the association between testosterone levels and lower body size and strength.
Results:
There was no difference in BMI among the three groups, but waist circumference was significantly larger in group 1 than in groups 2 and 3. When comparing weight-adjusted values, bilateral thigh circumference showed a significant difference among the three groups. There was also a significant difference between the three groups in the weight-adjusted left calf circumference and in the weight-adjusted right knee extension strength. The partial correlation test showed a significant positive correlation between thigh and calf circumference values adjusted for weight and serum testosterone levels. Weight-adjusted knee extension strength demonstrated a significant positive correlation with serum testosterone levels.
Conclusions
Weight-adjusted thigh and calf circumferences, along with the thigh-to-waist ratio, showed a positive correlation with testosterone levels. Weight-adjusted knee extension strength was positively correlated with testosterone levels. Therefore, a robust thigh and strong lower body are related to testosterone.
10.Effects of Combined Exercise Training on Symptoms and Physical Fitness in Young Adults with Mild Long COVID
Tae Gu CHOI ; Jae Yeop KIM ; Ho Jeong MIN ; Hyun Jeong KIM ; Kanokwan BUNSAWAT ; Setor K KUNUTSOR ; Kevin S HEFFERNAN ; Sae Young JAE
The Korean Journal of Sports Medicine 2025;43(1):1-12
Purpose:
The aim of this study was to examine whether a combined exercise (EX), including aerobic, resistance, and inspiratory muscle training, reduces fatigue and dyspnea, improves physical fitness, and if increased physical fitness after exercise is associated with attenuating symptoms in young adults with mild long coronavirus disease (COVID) symptoms.
Methods:
Twenty-eight young adults (aged 23±4 years) with long COVID were randomly assigned to either the EX group (n=14), which underwent aerobic, resistance, and inspiratory muscle training three times per week for 8 weeks, or the control (CON) group (n=14). Symptoms of dyspnea and fatigue were assessed using self-report questionnaires.Cardiorespiratory fitness was directly measured during cardiopulmonary exercise testing, while muscle strength was measured by isokinetic muscle testing. These variables were measured before and after the exercise intervention.
Results:
Compared to the CON group, the EX group showed improvements in symptoms of fatigue and dyspnea, maximal oxygen consumption (VO2peak ), and peak torque, with significant interaction effects observed (p< 0.05). The EX group exhibited a mean difference of 2.9 mL/kg/min in VO2peak (95% confidence interval [CI], 1.8−4.0) and 13.0 Nm (95% CI, 6.1−19.8) in peak torque compared to the CON group (p<0.05). Improvements in VO2peak were negatively associated with attenuations in both fatigue and dyspnea after the exercise intervention (p<0.05).
Conclusion
These findings indicate that EX training can effectively alleviate symptoms and improve physical fitness in young adults with mild long COVID. Structured exercise training may serve as an effective intervention to improve the health of those with long COVID.

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