Daroonwan Suksom

Continuous vs interval training on glycemic control and macro- and microvascular reactivity in type 2 diabetic patients.

To determine the effects of continuous aerobic exercise training (CON) vs interval aerobic exercise training (INT) on glycemic control and endothelium‐dependent vasodilatation, 43 participants with type 2 diabetes were randomly allocated to the sedentary, CON, and INT groups. The CON and INT exercise training programs were designed to yield the same energy expenditure/exercise session and included walking on treadmill for 30 and 40 min/day, 3 times/week for 12 weeks. Body fatness and heart rate at rest decreased and leg muscle strength increased (all P < 0.05) in both the CON and INT groups. Fasting blood glucose levels decreased (P < 0.05) in both exercise groups but glycosylated hemoglobin levels decreased (P < 0.05) only in the INT group. Maximal aerobic capacity, flow‐mediated dilation, and cutaneous reactive hyperemia increased significantly in both exercise groups; however, the magnitude of improvements was greater in the INT group. Only the INT group experienced reductions in erythrocyte malondialdehyde and serum von Willebrand factor and increases in plasma glutathione peroxidase and nitric oxide (all P < 0.05). We concluded that both continuous and interval training were effective in improving glycemic control, aerobic fitness, and endothelium‐dependent vasodilation, but the interval training program appears to confer greater improvements than the continuous training program.

Effects of Tai Chi Training on Antioxidant Capacity in Pre- and Postmenopausal Women

The risk of oxidative stress-related metabolic diseases increases with menopause and physical inactivity. We hypothesized that an 8-week Tai Chi (TC) training program (2 sessions in class; 2 sessions at home; 1-1:15/session) would improve antioxidant capacity and reduce cardiovascular risks in both pre- (n = 8) and postmenopausal (n = 7) sedentary women. Selected measures of physical fitness and blood parameters were analyzed before and after the program. Besides the well-known effects of TC on balance, flexibility, and maximum leg extensor strength, TC (1) increased erythrocyte glutathione peroxidase activity—an aerobic training-responsive antioxidant enzyme—and plasma total antioxidant status and (2) decreased plasma total homocysteine, a cardiovascular risk marker. In addition to being a low-velocity, low-impact, and relatively safe, TC is a suitable physical activity design for pre- and postmenopausal women to increase antioxidant defenses. Investigating breathing effects during TC movements would be an interesting area for further research in diseases prevention.

Increased NO bioavailability in aging male rats by genistein and exercise training: using 4, 5-diaminofluorescein diacetate

BackgroundSeveral kinds of anti-oxidants have drawn a lot of intension for their benefits on vascular protection. In addition, it has been demonstrated that exercise training could improve endothelial function by up-regulating endothelial nitric oxide synthase (eNOS) protein. Therefore, the present study aims to investigate the effects of genistein, a potent phyto-antioxidant, and exercise training on age-induced endothelial dysfunction in relation to NO bioavailability using in situ NO-sensitive fluorescent dye detection.MethodsMale Wistar rats (20-22-month old) were divided into four groups: aged rats treated with corn oil, (Aged+Veh, n = 5), aged rats treated with genistein (Aged+Gen, n = 5, (0.25 mg/kg BW/day, s.c.)), aged rats with and without exercise training (Aged+Ex, n = 5, swimming 40 min/day, 5 days/week for 8 weeks) (Aged+Without-Ex, n = 5). Cremaster arterioles (15-35 micrometer) were visualized by fluorescein isothiocyanate labeled dextran (5 microgram/ml). The vascular response to acetylcholine (Ach; 10-5M, 5 ml/5 min) was accessed after 1-min norepinephrine preconstriction (10 micro molar). To determine NO bioavailability, the Krebs-Ringer buffer with 4, 5-diaminofluorescein-diacetate (3 micro molar DAF-2DA), and 10 micro- molar Ach saturated with 95%N2 and 5%CO2 were used. Changes of DAF-2T-intensities along the cremaster arterioles were analyzed by the Image Pro-Plus Software (Media Cybernatics, Inc, USA). Liver malondialdehyde (MDA) level was measured by thiobarbituric acid reaction and used as an indicator for oxidative stress.ResultsThe results showed that means arterial blood pressure for both Aged+Gen and Aged+Ex groups were significantly reduced when compared to the Aged groups, Aged+Veh and Aged+Without-Ex (P < 0.05). Among the treated groups, Ach-induced vasodilatation were significantly increased (P < 0.05) and was associated with increased NO-associated fluorescent intensities (P < 0.05). On the other hand, MDA levels were significantly reduced (P < 0.05) when Aged+Veh was compared to Aged+Without-Ex.ConclusionThese findings showed that genistein and exercise training could improve age-induced endothelial dysfunction and is related to the increased NO bioavailability.

Arterial stiffness is associated with age-related differences in cerebrovascular conductance.

To determine if arterial stiffness is associated with age-related differences in cerebrovascular conductance and reactivity, twenty-eight apparently healthy sedentary young (25±1 years; n=15) and older (67±1 years; n=13) adults were studied. Brachial-ankle pulse wave velocity (baPWV) was measured as an index of arterial stiffness. Cerebrovascular reactivity was determined by measuring changes in mean blood velocity in the middle cerebral artery under normocapnic, hypocapnic and hypercapnic conditions. Mean baPWV was greater (p<0.05) in older compared with young adults. At baseline, mean cerebral blood flow velocity and cerebrovascular conductance index were lower (p<0.05) in older compared with young adults under normocapnic, hypocapnic and hypercapnic conditions. There were no significant group differences in cerebrovascular reactivity when they were adjusted for stimuli (i.e., end-tidal CO2 concentrations) in most perturbation conditions except for the normocapnia to hypercapnia condition. baPWV was negatively associated with cerebrovascular conductance index at all conditions (all p<0.05). We concluded that arterial stiffness was associated with age-related differences in cerebrovascular conductance and that there were no apparent age-associated differences in cerebrovascular reactivity.

The Relative Efficacy of Land-Based and Water-Based Exercise Training on Macro- and Microvascular Functions in Older Patients With Type 2 Diabetes

Microvascular and macrovascular dysfunction plays an important role in the pathogenesis of diabetic vascular disease. Twenty-nine older patients with type 2 diabetes were randomly assigned into the land-based (LB; n = 14) or water-based (WB; n = 15) groups. Both groups completed supervised aerobic cycling exercises three times per week for 12 weeks. The WB group performed cycling exercise training in warm water (36 °C) immersed to the hip level. After 12 weeks, blood glucose concentration and insulin resistance did not change but hemoglobin A1c levels decreased (P < .05) in both groups. Plasma nitric oxide concentrations increased (P < .05) in both groups. Flow-mediated dilation in the popliteal artery increased and arterial stiffness decreased (P < .05) in both exercise groups. Indices of microvascular reactivity improved (P < .05) only in the WB group. The benefits of warm water-based training were similar in general, and superior in some measures, to the more established land-based cycling exercise.

The Acute Effects of Supramaximal High-Intensity Intermittent Exercise on Vascular Function in Lean vs. Obese Prepubescent Boys

PURPOSE To determine the acute effects of high-intensity intermittent exercise (HIIE) on vascular function. METHODS Lean (n = 18, BMI = 17.1 ± 0.7) and obese (n = 17, BMI = 25.4 ± 0.8) prepubescent boys aged 10.2 ± 0.2 years were studied. HIIE consisted of 8 sets of 20 s of cycle ergometry at 100, 130, and 170% of VO2peak alternating with 10 s of rests. RESULTS The obese group had higher (p < .05) body mass, BMI, body fat percentage, waist-hip ratio than the lean group. Carotid artery wall thickness and arterial stiffness as assessed by brachial-ankle pulse wave velocity (baPWV) were greater in the obese than in the lean group (p < .05). Brachial artery flow-mediated dilation (FMD) was not different between the groups. Total energy expenditure increased gradually as the exercise intensity increased in both groups (p < .05). The obese group had significantly greater total energy expenditure in all three HIIE intensities than the lean group. FMD tended to be higher and baPWV lower as the exercise intensity increased in both groups. Only the HIIE at 170% demonstrated greater FMD compared with the baseline in both groups. baPWV decreased significantly after HIIE at 130 and 170% VO2peak in both groups. CONCLUSION Supramaximal HIIE can be a feasible exercise modality for improving vascular function in obese prepubescent boys. Future exercise intervention studies are warranted.

Cell-derived microparticles after exercise in individuals with G6PD Viangchan

Glucose-6-phospate dehydrogenase (G6PD) deficient cells are sensitive to oxidative damage leading to the formation of microparticles (MPs). Therefore, we examined the concentration of MPs and changes in the antioxidant balance after an acute strenuous exercise (SEx) and moderate-intensity exercise (MEx). Eighteen healthy females (18-24 years) with G6PD normal and eighteen age-matched females with G6PD Viangchan (871G>A) were tested by running on a treadmill at their maximal oxygen uptake for SEx and at 75% of their maximal heart rate for MEx. It was found that SEx triggered the release of total microparticles (TTMPs) above baseline levels and remained significantly higher 45 minutes after the exercise in G6PD normal individuals. However, SEx-induced increase in TTMPs was significantly higher in G6PD Viangchan as compared to G6PD normal. In contrast, MEx did not to alter the release of TTMPs in both G6PD normal and Viangchan. Moreover, TTMPs concentrations were inversely correlated with G6PD activity (r =-0.82, P <  0.05) but positively correlated with MDA concentrations (r = 0.74, P <  0.05). Using cell specific antibodies, we determined that MPs were mainly derived from platelets and erythrocytes. Altogether, the present study indicates that G6PD Viangchan may participate in MEx without higher MPs concentration and oxidative stress compared with G6PD normal.

Antioxidant status in haemoglobin E carriers after acute and chronic strenuous exercises

Haemoglobin E (HbE), an unstable haemoglobin, is highly susceptible to oxidative damages. We examined how acute or chronic physiological challenge induced by exercise affects antioxidant response in HbE carriers. Two independent studies were conducted in individuals with HbE trait and paired normal Hb. In study 1, sedentary participants were tested in a graded maximal exercise and blood samples were collected before, immediately after, and 45 minutes after an acute exercise. Our data showed that erythrocyte glutathione peroxidase (GPx) activity failed to recover in HbE carriers after 45 minutes of rest. In study 2, athletes were trained in a 10-week strenuous training and blood samples were collected before and after training period. We found that athletes with HbE carriers showed a larger increase in plasma GPx activity compared to those with normal Hb. These data suggest that HbE carriers could cope with exercise-induced oxidative stress by adjusting endogenous antioxidant markers.

Mind–Body Exercises

We enjoyed reading the recent review article by Blair Kennedy and Resnick discussing the interaction between mindfulness and physical activity. We agree with the authors that mindfulness and mindful activity can have a profound effect on physical and psychological health. We also argue that when these mindful activities are combined with physical activity, the beneficial effects would be greater. As the authors reviewed in the article, a typical approach for studying the mind–body interaction is to focus on the activities that naturally combine mindfulness and physical activity. A lot of traditional activities in existence from the ancient times, including yoga, tai chi, and kouksun-do, fall into this category. However, the format and the organization of these mind–body exercises may be too rigid to be adapted by people with different cultures and customs. An alternative approach to study this would be to incorporate a mindful activity into standard exercise programs that have been shown to be effective. One of such examples is Buddhism walking meditation. It incorporates the basic principles of traditional meditation performed in the sitting position, including breathing, awareness, concentration, and relaxation, with rhythmic exercise of standard walking. In a study using depressed elderly, Buddhism walking meditation produced improvements in functional fitness and vascular function that were equivalent to those induced by the traditional walking program. More notably, only the walking meditation resulted in a significant reduction in depression scores and blood concentration of cortisol. This kind of activity is particularly attractive in Thailand where the study was conducted. As 95% of the populations in Thailand practice Buddhism, it can be practiced and accepted by the majority of the population. Poor adherence and compliance to exercise programs have been well known. As Blair Kennedy and Resnick implied, integrating mindfulness is one way to enhance exercise adherence even though currently no such evidence exists. These effects may be greater if religion-based mindful activity was incorporated into standard exercise as the practice in religions is a life-long commitment for most people. This kind of holistic approach incorporating mind–body exercises is consistent with the current guidelines for lifestyle modifications. The exercise prescription schemes had focused primarily on aerobic exercise in the past. But more recent exercise prescriptions include and target a variety of other fitness components (muscle strength and power, flexibility) as evidenced by the recent popularity of cross-training programs (eg, cross-fit). Time may come in the near future to newly include mindful components into the overall health and fitness promotion. But to do so, we need to accumulate more research evidence to support such practices. AJLM