Interactions between oxidative stress and cardiorespiratory fitness: Old and new biomarkers

A Functional Drink Containing Kaempferia parviflora Extract Increases Cardiorespiratory Fitness and Physical Flexibility in Adult Volunteers

Owing to the reputation of Kaempferia parviflora and the crucial role of oxidative stress on the disturbance of physical fitness, the effect of a functional drink containing K. parviflora extract (KP) on the physical fitness of healthy adult volunteers was assessed. Healthy male and female volunteers (19-60 years old) were randomly divided into placebo, KP90, and KP180 groups. All the subjects in KP90 and KP180 were directed to consume a functional drink containing K. parviflora extract at doses of 90 and 180 mg per serving per 80 mL, respectively. Parameters of physical fitness, including cardiovascular endurance, muscular strength and endurance, flexibility, and body composition, together with changes in lactate, creatinine kinase, and oxidative stress markers were assessed before the intervention, and at 6 and 12 weeks of intervention. The oxidative stress markers, creatine kinase, and lactate were also measured. Subjects who consumed the developed drink had increased VO2 max and improved performance in a timed shuttle run test and 5 min distance run, and exhibited decreased oxidative stress and lactate; therefore, K. parviflora extract can be successfully used for developing a KP drink to improve cardiorespiratory fitness and physical performance by improving oxidative stress and lactate.

Correlates of Early-Stage Frailty-Sleep, Fitness, Oxidative Stress, and BMI

Frailty reflects a decreased reserve in multiple systems resulting from cumulative decline. Frailty markers should be identified as early as possible to attenuate the loss of reserve. The aim of this study was to identify potentially modifiable correlates of frailty in relatively healthy older adults. Volunteers (n = 122) were recruited from local councils and, based on gender and age, were divided into one group of men aged 77.0 (±5.3), and two groups of women, aged 68.8 (±3.6) and aged 78.4 (±3.4). Frailty was assessed by a Frailty Index. The examined correlates were: physical activity, physical fitness (predicted peak VO₂), sleep quality, oxidative stress (hydrogen peroxide-H₂O₂) and depression. Both groups of women had poor scores on physical fitness compared to women's norms. In order to examine the contribution of each of the potential correlates to explaining the variance of frailty, stepwise regressions were performed for each group separately. Based on the results, none of the suggested correlates significantly explained the variability of frailty in the men. In the younger-aged women, predicted peak VO₂ and sleep quality explained 22.4% of the variability of frailty. In the older women, Body Mass Index (BMI), oxidative stress and sleep quality explained 34.9% of the variance. It is possible that increased aerobic fitness and interventions for improving sleep quality in older, seemingly healthy women will slow down the frailty process. Further research is needed to assess potential correlates of frailty, and to initiate suitable interventions to mitigate the signs of frailty at an early stage.

Association Between Diet Quality and Cardiorespiratory Fitness in Korean Adults: The 2014-2015 National Fitness Award Project

Cardiorespiratory fitness (CRF) is a strong and meaningful indicator for predicting mortality, including cardiovascular disease, as well as simple physical capacity. Healthy eating is thought to be one of the crucial factors associated with an individual's CRF status, although little research has been done on the relationship between healthy eating and CRF. This study aimed to investigate the association between overall diet quality and CRF among Korean adults. The study involved 937 adults (380 men and 557 women) aged 19‒64 years who participated in the 2014‒2015 Korea Institute of Sports Science Fitness Standards project. Diet quality was assessed by the recommended food score (RFS), and CRF was determined by maximal oxygen uptake (VO2max) during a treadmill exercise test. Multiple regression model analyses were stratified by age (19-34, 35-49, and 50-64 years) and sex, because both factors greatly influence CRF. After multivariate adjustment, only the 19‒34 age group in both sexes showed a positive association between RFS and VO2max. Additionally, when physical activity was adjusted, it was still significant in men but only marginally related in women. Our results suggest that better overall diet quality may be associated with a better CRF among young adults aged 19‒34 years in Korea.