Abstract

DNAmPhenoAge, DNAmGrimAge, and the newly developed DNAmFitAge are DNA methylation (DNAm)-based biomarkers that reflect the individual aging process. Here, we examine the relationship between physical fitness and DNAm-based biomarkers in adults aged 33–88 with a wide range of physical fitness (including athletes with long-term training history). Higher levels of VO₂max (ρ = 0.2, p = 6.4E − 4, r = 0.19, p = 1.2E − 3), Jumpmax (p = 0.11, p = 5.5E − 2, r = 0.13, p = 2.8E − 2), Gripmax (ρ = 0.17, p = 3.5E − 3, r = 0.16, p = 5.6E − 3), and HDL levels (ρ = 0.18, p = 1.95E − 3, r = 0.19, p = 1.1E − 3) are associated with better verbal short-term memory. In addition, verbal short-term memory is associated with decelerated aging assessed with the new DNAm biomarker FitAgeAcceleration (ρ: − 0.18, p = 0.0017). DNAmFitAge can distinguish high-fitness individuals from low/medium-fitness individuals better than existing DNAm biomarkers and estimates a younger biological age in the high-fit males and females (1.5 and 2.0 years younger, respectively). Our research shows that regular physical exercise contributes to observable physiological and methylation differences which are beneficial to the aging process. DNAmFitAge has now emerged as a new biological marker of quality of life.

Although many studies have reported that a posteriori dietary pattern is associated with metabolic health, there is little evidence of an association between dietary patterns and different metabolic phenotypes. The present study aimed to examine the association between major dietary patterns and different metabolic phenotypes (metabolically healthy non-obese [MHNO], metabolically unhealthy non-obese [MUNO], metabolically healthy obese [MHO], and metabolically unhealthy obese [MUO]) in middle-aged and elderly Japanese adults. This cross-sectional study enrolled 2,170 Japanese adults aged ≥40 years. The four different metabolic phenotypes were determined based on the presence of obesity, abdominal obesity, hypertension, hyperglycemia, and dyslipidemia. The major dietary patterns were determined using principal component analysis based on energy-adjusted food intake. Two dietary patterns were identified: the healthy dietary pattern, which was characterized by a high intake of vegetables, fruits, potatoes, soy products, mushrooms, seaweeds, and fish; and the alcohol dietary pattern, which was characterized by a high intake of alcoholic beverages, liver, chicken, and fish. The healthy dietary pattern was associated with the MHNO and MHO phenotypes (MUNO and MUO as reference groups, respectively), and the multivariate-adjusted odds ratios (ORs) (95% confidence intervals [CIs]) in the highest quartile of healthy dietary pattern score with the lowest quartile as the reference category were 2.10 (1.40-3.15) and 1.86 (1.06-3.25), respectively. Conversely, the alcohol dietary pattern was inversely associated with the MHNO and MHO phenotypes, while the multivariate-adjusted ORs (95% CIs) in the highest quartile of the alcohol dietary pattern score with the lowest quartile as the reference category were 0.63 (0.42-0.94) and 0.45 (0.26-0.76), respectively. There were no significant interactions between sex and healthy/alcohol dietary patterns in the prevalence of the MHNO and MHO phenotypes. In conclusion, the present study's findings suggest that major dietary patterns are associated with different metabolic phenotypes in middle-aged and elderly Japanese adults. These findings provide useful evidence for maintaining metabolic health through diet regardless of obesity status.

The relationships between cardiorespiratory fitness (CRF) measurements not confounded by adiposity and the prevalence of pre-diabetes mellitus (pre-DM) and diabetes mellitus (DM) are not well known. Thus, we aimed to investigate the associations of visceral fat (VF) and CRF with the prevalence of pre-DM/DM among Japanese adults. The study included 970 individuals (327 women and 643 men) who were 40-87 years old and had complete health examinations, abdominal fat area, and fitness data from WASEDA'S Health Study during 2015-2018. The VF area was measured using magnetic resonance imaging. CRF was measured using a cycle ergometer and was defined as VO2peak divided by fat free mass. The pre-DM/DM was identified based on the questionnaire and fasting blood tests. The odds ratios (ORs) and 95% confidence intervals (CIs) for prevalence of pre-DM/DM were calculated. Seventy-three participants had pre-DM and 48 participants had DM. Compared to the low VF group, the high VF group had a higher prevalence of pre-DM/DM (OR: 1.87, 95% CI: 1.18-2.96), although no significant relationship was observed between CRF and pre-DM/DM prevalence (P for trend = 0.239). The sub-group analyses also revealed no significant relationship between CRF and pre-DM/DM prevalence in the low VF group (P for trend = 0.979), although CRF values were inversely related to the prevalence of pre-DM/DM in the high VF group (P for trend = 0.024). Although CRF was not independently related to the prevalence of pre-DM/DM after adjusting for adiposity, higher VF values were related to a higher prevalence of pre-DM/DM. In addition, CRF levels were inversely associated with the prevalence of pre-DM/DM only among high VF individuals.

BACKGROUND: Preceding exercise enhances fat metabolism during subsequent endurance exercise. However, it is unknown which type of exercise most enhances fat metabolism during subsequent exercise. The aim of this study was to examine the influence of preceding resistance or endurance exercise on fat metabolism during subsequent endurance exercise and to compare the effect with that without a preceding exercise.METHODS: Nine male subjects performed the following trials: 1) endurance exercise (E trial), 2) endurance exercise preceded by resistance exercise (R+E trial), and 3) endurance exercise preceded by endurance exercise (E+E trial). There was a 20-min break after the preceding exercise. Subsequent endurance exercise was performed on a cycle ergometer at 80% of the individual ventilatory threshold. Blood and exhaled gas were analyzed respectively.RESULTS: The R+E and E+E trials showed a significantly lower respiratory exchange ratio (RER) and a higher amount of fat oxidation during endurance exercise than those in the E trial (P<0.05). Furthermore, the E+E trial showed a significantly lower RER (0.86 +/- 0.03 vs. 0.84 +/- 0.02) and a significantly higher amount of fat oxidation (0.38 +/- 0.05 g/min vs. 0.44 +/- 0.08 g/min) than those in the R+E trial.CONCLUSIONS: This study suggested that fat oxidation during subsequent endurance exercise was enhanced when a preceding exercise was performed and that endurance exercise as a preceding exercise enhanced fat oxidation more than resistance exercise did.

Molecular hydrogen (H2) is a colorless, tasteless, odorless, and minimal molecule with high flammability. Although H2 has been thought to be an inert gas in living bodies for many years, an animal study reported that inhalation of H2 gas decreased oxidative stress and suppressed brain injury caused by ischemia and reperfusion injury due to its antioxidant action. Since then, the antioxidant action of H2 has attracted considerable attention and many studies have reported on its benefits. Most studies have reported the effects of H2 on diseases such as cancer, diabetes, cerebral infarction, and Alzheimer's disease. However, little is known regarding its effects on healthy subjects and exercise. Thus far, including our study, only 6 studies have explored the effect of H2 on exercise. H2 is the smallest molecule and therefore can easily penetrate the cellular membrane and rapidly diffuse into organelles. H2 is thought to be able to selectively reduce hydroxyl radicals and peroxynitrite and does not affect physiologically reactive species. H2 can be supplied to the body through multiple routes of administration, such as oral intake of H2 water and H2 bathing. Therefore, H2 may be a potential alternative strategy for conventional exogenous antioxidant interventions in sports science. The purpose of this review is to provide evidence regarding the effects of H2 intake on changes in physiological and biochemical parameters, centering on exercise-induced oxidative stress, for each intake method. Furthermore, this review highlights possible future directions in this area of research.

The purpose of this study was to investigate the involvement of neutrophil dynamics and function in exercise-induced muscle damage (EIMD) and delayed-onset muscle soreness (DOMS), and the effect of molecular hydrogen (H₂) intake on these parameters. Nine healthy and active young men performed H₂ and placebo bath trial in a crossover design. They carried out downhill running (-8% slope) for 30 min at a speed corresponding to 75~85% of peak oxygen uptake (VO₂peak). Subsequently, they repeated bathing for 20 min per day for one week. Degree of muscle soreness (visual analogue scale: VAS), peripheral leukocyte counts, neutrophil dynamics and function, muscle damage, and inflammation markers were measured. Plasma interleukin (IL)-6 concentration was significantly correlated with peripheral neutrophil count, VAS, and serum creatine kinase activity, respectively, after downhill running. Peripheral neutrophil count and serum myoglobin concentration were also significantly correlated. Conversely, there were no effects of H₂ bath. These results suggest that IL-6 may be involved in the mobilization of neutrophils into the peripheral blood and subsequent EIMD and DOMS after downhill running; however, it is not likely that H₂ bath is effective for the inflammatory process that was centered on neutrophils after downhill running.

Objectives: The purpose of this study was to examine the effects of exhaustive exercises, with different intensities, on oxidative stress markers in rat plasma and skeletal muscle. Methods: Male Sprague-Dawley rats (n = 24) were randomly divided into the following four groups: control (CON), low-intensity exercise (LE), high-intensity interval exercise (HE) and incremental exercise (IE). The animals in the latter three groups performed exercises in which they ran until exhaustion as follows: Animals in the LE group ran at 20 m/min (6° graded)
the HE group ran at 40 m/min for 30 s (0° graded) with a rest interval of 60 s between each run
and the IE group ran at 15 m/min (6° graded), initially, with the running speed gradually increased by 5 m/min, every 10 min. Immediately following the exercise, a blood sample was drawn, and followed by the gastrocnemius muscle and liver were quickly removed. These samples were analysed for lactate concentration, oxidative stress markers, and glycogen contents. Results: Plasma oxidative stress markers in the LE and HE groups demonstrated no change, while plasma protein carbonyl (PC) levels and total antioxidant capacity (TAC) in the IE group were significantly increased compared with the CON group (P &lt
0.05). In contrast, all the oxidative stress markers, in the skeletal muscle of the three exercise groups, demonstrated no change compared with the CON group. Conclusion: Incremental exhaustive exercise elevates the plasma PC levels and TAC, but does not change skeletal muscle oxidative stress markers in rats.

It is known that a high-fat diet induces an increase in mitochondrial biogenesis in skeletal muscle. To examine the time course of decrease in mitochondrial biogenesis in skeletal muscle after discontinuing a high-fat diet feeding, C57BL/6 mice were fed a high-fat diet for 4 wk and then switched to the control diet for another 3 or 7 d. During the high-fat diet withdrawal period, the protein content of the mitochondrial respiratory chain decreased faster than the fatty acid oxidation enzymes. The mitochondrial DNA copy number remained high for at least 1 wk after withdrawing the high-fat diet. These results suggested that after switching to the control diet following a period of high-fat diet, the increased mitochondrial biogenesis levels are maintained for a few days, and the rate of decline is divergent between the different mitochondrial components.

Long-term high-fat diet increases muscle mitochondrial enzyme activity and endurance performance. However, excessive calorie intake causes intra-abdominal fat accumulation and metabolic syndrome. The purpose of this study was to investigate the effect of an alternating day high-fat diet on muscle mitochondrial enzyme activities, protein content, and intra-abdominal fat mass in rats. Male Wistar rats were given a standard chow diet (CON), high-fat diet (HFD), or alternate-day high-fat diet (ALT) for 4 weeks. Rats in the ALT group were fed a high-fat diet and standard chow every other day for 4 weeks. After the dietary intervention, mitochondrial enzyme activities and protein content in skeletal muscle were measured. Although body weight did not differ among groups, the epididymal fat mass in the HFD group was higher than those of the CON and ALT groups. Citrate synthase and beta-hydroxyacyl CoA dehydrogenase activities in the plantaris muscle of rats in HFD and ALT were significantly higher than that in CON rats, whereas there was no difference between HFD and ALT groups. No significant difference was observed in muscle glycogen concentration or glucose transporter-4 protein content among the three groups. These results suggest that an alternate-day high-fat diet induces increases in mitochondrial enzyme activities and protein content in rat skeletal muscle without intra-abdominal fat accumulation.