Hypertension and exercise

The effect of body mass index and physical activity on hypertension among Chinese middle-aged and older population

Few studies have been conducted to explore the independent and combined associations of body mass index (BMI) and physical activity with risk of hypertension in Chinese population. A cross-sectional study of 5291 individuals (aged ≥ 40 years) selected using multi-stage sampling method was conducted from October 2013 to December 2015. In the present analysis, 55.64% of the participants were women, and the mean age of participants was 55.37 ± 10.56. Compared with individuals in normal group, the risks of hypertension were nearly double in overweight subjects (odds ratio [OR] 1.77, 95% confidence interval [CI] 1.53–2.05) and more than three times higher in obese subjects (3.23, 2.62–4.13). Multi-adjusted odds for hypertension associated with low, moderate, and high physical activity were 1.44 (1.17–1.86), 1.40 (1.09–1.79) and 1.000, respectively. In comparison with normal weight subjects who reported high levels of physical activity, subjects who reported both low levels of physical activity and obesity showed the highest risk of hypertension (5.89, 3.90–8.88). In conclusion, both elevated BMI and reduced physical activity appear to play an important role in the risk of hypertension among Chinese middle-aged and older population. The risk of hypertension associated with overweight and obesity can be reduced considerably by increased physical activity levels.

The Importance of Walking for Control of Blood Pressure: Proof Using a Telemedicine System

BACKGROUND

Regular physical activity (PA), including daily walking, reduces the risk of many chronic diseases, especially hypertension. Pedometer is a potential motivational aid for increasing PA. In the present study, we used a telemedicine system and analyzed the relationship between daily walking, calculated by pedometers, and blood pressure (BP).

METHODS

BP was measured at home twice a day (morning and evening) using an oscillometric automatic device. Body weight (BW) and percent body fat (%BF) were measured after BP measurement. Daily walking steps (DWS) were calculated by a pedometer. These daily parameters were transmitted through the Internet to a central server computer and sent to the Medical Health Center.

RESULTS

Sixty-nine (N = 69) hypertensive patients were included in this study. The mean follow-up period was 378 days. Electronic data from a pedometer (DWS) were associated with reduced BW, body mass index, and %BF. Hypertensive patients were divided into two groups based on the DWS. In the high DWS group, morning systolic BP and diastolic BP and evening systolic BP were reduced after induction of the telemedicine system.

CONCLUSION

A telemedicine system confirmed the usefulness of walking to control BP in hypertensive patients.

Exercise Training Reverses Structural Microvascular Rarefaction and Improves Endothelium-Dependent Microvascular Reactivity in Rats with Diabetes

BACKGROUND

We evaluated structural microvascular alterations in the skeletal muscle and left ventricle, as well as endothelium-dependent microvascular reactivity in the skeletal muscle, of diabetic rats subjected to long-term aerobic exercise training.

METHODS

Diabetes was experimentally induced by a combination of a high-fat diet with a single low dose of streptozotocin (35 mg/kg, i.p.). Animals with diabetes were divided into sedentary (DM+SED) and training groups (DM+TR) and compared with rats without diabetes (CON). We then measured maximal exercise capacity, fasting glucose and insulin, endothelium-dependent microvascular reactivity in skeletal muscle, and structural alterations of microvasculature in the skeletal and cardiac muscles.

RESULTS

Diabetes induced microvascular rarefaction and reduced endothelium-dependent microvascular reactivity. Physical exercise completely reversed microvascular rarefaction in the skeletal muscle (1.85 ± 0.05 vs. 1.17 ± 0.03 capillary/fiber ratio, P < 0.05) and in the left ventricle (0.48 ± 0.66 vs. 0.25 ± 0.01 Vv[cap]/Vv[fib] ratio, P < 0.05) compared with the DM+SED group and normalized the microcirculatory responses to acetylcholine in skeletal muscle (CON 38.76 ± 5.60 vs. DM+TR 30.47% ± 5.77%). As expected, exercise training increased the maximal velocity and exercise tolerance compared with the DM+SED (P < 0.05) and CON (P < 0.05) groups. Exercise training also reduced fasting glucose (P < 0.05) compared with DM+SED and normalized insulin levels compared with CON.

CONCLUSIONS

Our results suggest that long-term physical exercise reverses skeletal and cardiac muscle microvascular rarefaction, as well as impaired endothelium-dependent microvascular reactivity, induced by diabetes in rats.

Physical exercise restores microvascular function in obese rats with metabolic syndrome

BACKGROUND

Obesity and metabolic syndrome are related to systemic functional microvascular alterations, including a significant reduction in microvessel density. The aim of this study was to investigate the effects of exercise training on functional capillary density in the skeletal muscle and skin of obese rats with metabolic syndrome.

METHODS

We used male Wistar-Kyoto rats that had been fed a standard commercial diet (CON) or high-fat diet (HFD) for 32 weeks. Animals receiving the HFD were randomly divided into sedentary (HFD+SED) and training groups (HFD+TR) at the 20(th) week. After 12 weeks of aerobic treadmill training, the maximal oxygen uptake (VO2max); hemodynamic, biochemical, and anthropometric parameters; and functional capillary density were assessed. In addition, a maximal exercise test was performed.

RESULTS

Exercise training increased the VO2max (69 ± 3 mL/kg per min) and exercise tolerance (30 ± 1 min) compared with the HFD+SED (41 ± 6 mL/kg per min, P < 0.05 and 16 ± 1 min, P < 0.001) and with the CON (52 ± 7 mL/kg per min and 18 ± 1 min, P < 0.05) groups. The HFD+TR group also showed reduced retroperitoneal fat (0.03 ± 0.00 vs. 0.05 ± 0.00 gram/gram, P < 0.001), epididymal fat (0.01 ± 0.00 vs. 0.02 ± 0.00 gram/gram, P < 0.001), and systolic blood pressure (127 ± 2 vs. 150 ± 2 mmHg, P<0.001). The HFD+TR group also demonstrated improved glucose tolerance, as evaluated by an intraperitoneal glucose tolerance test, fasting plasma glucose levels (5.0 ± 0.1 vs. 6.4 ± 0.2 mmol/L, P<0.001) and fasting plasma insulin levels (26.5 ± 2.3 vs. 38.9 ± 3.7 μIU/mL, P < 0.05). Glucose tolerance did not differ between HFD+TR and CON groups. Exercise training also increased the number of spontaneously perfused capillaries in the skeletal muscle (252 ± 9 vs. 207 ± 9 capillaries/mm(2)) of the training group compared with that in the sedentary animals (260 ± 15 capillaries/mm(2)).

CONCLUSIONS

These results demonstrate that exercise training reverses capillary rarefaction in our experimental model of metabolic syndrome and obesity.

Exercise Training suppresses vascular fibrosis in aging obesity induced rats

[Purpose]

The aim of this study was to investigate the effects of exercise training (ET) on vascular fibrosis in aging model rats with diet-induced obesity.

[Methods]

Twenty-four male Sprague-Dawley rats were divided into 3 groups: Aging control (A-C), A-C with high fat diet (AHF), AHF with ET (AHF + ET). Aging was induced by D-galactose (D-gal) and obesity was induced by HFD (60% fat) for 9 weeks. The experimental rats performed swimming (60 min/day, 5 days/week) for 8 weeks. All rat aorta samples were harvested for RT-PCR and morphologic analyses.

[Results]

The exercise training significantly decreased levels of AT-1, TGF-ß and Coll-1 gene expression compared to AHF group. The AHF + ET group showed a reduced collagen accumulation in the aorta media compared to AHF group.

[Conclusion]

These results suggest that ET could protect the aging obesity aorta against down-regulation of fibrotic factors (AT-1, TGF-ß and Coll-1 gene) and fibrosis by inhibition of collagen accumulation in the aorta media.

Swimming exercise changes hemodynamic responses evoked by blockade of excitatory amino receptors in the rostral ventrolateral medulla in spontaneously hypertensive rats

Exercise training reduces sympathetic activity in hypertensive humans and rats. We hypothesized that the swimming exercise would change the neurotransmission in the rostral ventrolateral medulla (RVLM), a key region involved in sympathetic outflow, and hemodynamic control in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. Bilateral injections of kynurenic acid (KYN) were carried out in the RVLM in sedentary- (S-) or exercised- (E-) SHR and WKY rats submitted to swimming for 6 weeks. Rats were α-chloralose anesthetized and artificially ventilated, with Doppler flow probes around the lower abdominal aorta and superior mesenteric artery. Injections into the RVLM were made before and after i.v. L-NAME (nitric oxide synthase, NOS, inhibitor). Injections of KYN into the RVLM elicited a major vasodilation in the hindlimb more than in the mesenteric artery in E-SHR compared to S-SHR, but similar decrease in arterial pressure was observed in both groups. Injections of KYN into the RVLM after i.v. L-NAME attenuated the hindlimb vasodilation evoked by KYN and increased the mesenteric vasodilation in E-SHR. Swimming exercise can enhance the hindlimb vasodilation mediated by peripheral NO release, reducing the activation of neurons with EAA receptors in the RVLM in SHR.

Autonomic Cardiovascular Damage during Post-menopause: the Role of Physical Training

Menopause is part of the aging process and is characterized by the natural cessation of menstruation; during this time, the production of ovarian hormones, especially estrogen, is sharply reduced. This reduction can cause symptoms and disorders that affect most women and can interfere with their quality of life. Women are also more susceptible to cardiovascular diseases during this period, considering that these ovarian hormones would be associated with a protective effect on the cardiovascular system, by acting at various levels, contributing to the body homeostasis. Among several effects on the cardiovascular system, the ovarian hormones seem to play an important role in the autonomic control of heart rate and blood pressure. A reduction in ovarian hormones causes an autonomic imbalance and increases the risk of cardiovascular diseases. In fact, this increased risk is justified by the key role the autonomic nervous system plays in all cardiac regulatory mechanisms, exerting a tonic and reflexive influence on the main variables of the cardiovascular system. The autonomic system controls various cardiovascular parameters, such as the modulation of heart rate and blood pressure, myocardial contractility and venous capacitance, directly participating in the regulation of cardiac output. Over the years, the standard treatment for menopause symptoms and disorders has been hormone replacement therapy (HRT). However, many studies have indicated the risks of HRT, which justify the need for new non-pharmacological therapies. To this end, physical training, mainly aerobic, has been applied with excellent results on the cardiovascular autonomic nervous system, as it reduces the risk of cardiac diseases and improves the survival rate with direct beneficial effects on the quality of life of these women during the aging process.

Effects of Short-term Exercise Training on Cardiorespiratory Fitness of Male Adults with Myocardial Infarction

[Purpose] The purpose of this study was to determine the effects of short-term exercise training on the cardiorespiratory fitness (CRF) of individuals suffering from myocardial infarction. [Subjects] A total of 60 participants were divided into experimental (EXP; n=30, mean age 56.7 ± 2.8 years, body mass 80.7 ± 10.7 kg, body height 171.9 ± 7.2 cm) and control (CON; n=30, mean age 56.5 ± 3.1 years, body mass 84.4 ± 12.4 kg, body height 171.5 ± 12.4 cm) groups. [Methods] The members of the EXP group took part in an organized daily physical exercise program (Monday through Sunday), for a period of 3 weeks. The exercise program consisted of 60 min daily specialized fitness exercises with an intensity ranging from 55-70% of the maximum heart rate, which was determined by test on a bicycle ergometer. The effects of the exercise were monitored by means of the following parameters: maximum oxygen uptake (VO2peak), resting heart rate, systolic blood pressure and diastolic blood pressure. [Results] The results indicate statistically significant post-exercise improvements in heart rate, relative oxygen uptake and systolic blood pressure, among the members of the EXP group. The results indicate that at the initial measurement of cardiorespiratory fitness no statistically significant differences were found between the groups at the multivariate level (Wilk's λ=0.83), while statistically significant differences in the cardiorespiratory fitness were found at the final measurement (Wil's λ=0.430). [Conclusion] The obtained results indicate that the exercise program, which lasted for a period of 21 days, though shorter in duration than other programs still led to statistically significant changes in the CRF of individuals suffering from MI.

Decreased erythrocyte NA+,K+-ATPase activity and increased plasma TBARS in prehypertensive patients

The essential hypertension has been associated with membrane cell damage. The aim of the present study is investigate the relationship between erythrocyte Na⁺,K⁺-ATPase and lipoperoxidation in prehypertensive patients compared to normotensive status. The present study involved the prehypertensive patients (systolic: 136 ± 7 mmHg; diastolic: 86.8 ± 6.3 mmHg; n = 8) and healthy men with normal blood pressure (systolic: 110 ± 6.4 mmHg; diastolic: 76.1 ± 4.2 mmHg; n = 8) who were matched for age (35 ± 4 years old). The venous blood samples of antecubital vein (5 mL) were collected into a tube containing sodium heparin as anticoagulant (1000 UI), and erythrocyte ghosts were prepared for quantifying Na⁺,K⁺-ATPase activity. The extent of the thiobarbituric acid reactive substances (TBARS) was determined in plasma. The statistical analysis was carried out by Student's t-test and Pearson's correlation coefficient. A P < 0.05 was considered significant. The Na⁺,K⁺-ATPase activity was lower in prehypertensive patients compared with normotensive subjects (4.9 versus 8.0 nmol Pi/mg protein/min; P < 0.05). The Na⁺,K⁺-ATPase activity correlated negatively with TBARS content (r = −0.6; P < 0.05) and diastolic blood pressure (r = −0.84; P < 0.05). The present study suggests that Na⁺,K⁺-ATPase activity reduction and elevation of the TBARS content may underlie the pathophysiological aspects linked to the prehypertensive status.

Exercise changes regional vascular control by commissural NTS in spontaneously hypertensive rats

Inhibition of the commissural nucleus of the solitary tract (commNTS) induces a fall in sympathetic nerve activity and blood pressure in spontaneously hypertensive rats (SHR), which suggests that this subnucleus of the NTS is a source of sympathoexcitation. Exercise training reduces sympathetic activity and arterial pressure. The purpose of the present study was to investigate whether the swimming exercise can modify the regional vascular responses evoked by inhibition of the commNTS neurons in SHR and normotensive Wistar-Kyoto (WKY) rats. Exercise consisted of swimming, 1 h/day, 5 days/wk for 6 wks, with a load of 2% of the body weight. The day after the last exercise session, the rats were anesthetized with intravenous α-chloralose, tracheostomized, and artificially ventilated. The femoral artery was cannulated for mean arterial pressure (MAP) and heart rate recordings, and Doppler flow probes were placed around the lower abdominal aorta and superior mesenteric artery. Microinjection of 50 mM GABA into the commNTS caused similar reductions in MAP in swimming and sedentary SHR (−25 ± 6 and −30 ± 5 mmHg, respectively), but hindlimb vascular conductance increased twofold in exercised vs. sedentary SHR (54 ± 8 vs. 24 ± 5%). GABA into the commNTS caused smaller reductions in MAP in swimming and sedentary WKY rats (−20 ± 4 and −16 ± 2 mmHg). Hindlimb conductance increased fourfold in exercised vs. sedentary WKY rats (75 ± 2% vs. 19 ± 3%). Therefore, our data suggest that the swimming exercise induced changes in commNTS neurons, as shown by a greater enhancement of hindlimb vasodilatation in WKY vs. SHR rats in response to GABAergic inhibition of these neurons.

Preventing and managing cardiometabolic risk: the logic for intervention

Cardiometabolic risk (CMR), also known as metabolic syndrome or insulin resistance syndrome, comprises obesity (particularly central or abdominal obesity), high triglycerides, low HDL, elevated blood pressure, and elevated plasma glucose. Leading to death from diabetes, heart disease, and stroke, the root cause of CMR is inadequate physical activity, a Western diet identified primarily by low intake of fruits, vegetables, and whole grains, and high in saturated fat, as well as a number of yet-to-be-identified genetic factors. While the pathophysiological pathways related to CMR are complex, the universal need for adequate physical activity and a diet that emphasizes fruits and vegetables and whole grains, while minimizing food high in added sugars and saturated fat suggests that these behaviors are the appropriate focus of intervention.

Effect of exercise training on resistance arteries in rats with chronic NOS inhibition

Regular exercise has blood pressure-lowering effects, as shown in different types of experimental hypertension models in rats, including the nitric oxide synthase (NOS) inhibition model. We aimed to investigate possible mechanisms implicated in the exercise effect by evaluating the vasoreactivity of resistance arteries. Exercise effects on agonist-induced vasodilatory responses and flow-mediated dilation were evaluated in vessel segments of the rat chronic NOS inhibition model. Normotensive and hypertensive rats were subjected to swimming exercise (1 h/day, 5 days/wk, 6 wk), while rats in other sedentary and hypertensive groups did not. Hypertension was induced by oral administration of the nonselective NOS inhibitor l-NAME (25 mg/kg day) for 6 wk. Systolic blood pressure, as measured by the tail-cuff method, was significantly decreased by the training protocol in exercising hypertensive rats. The vasoreactivity of resistance arteries was evaluated by both wire and pressure myography studies. An impaired nitric oxide-mediated relaxation pathway in untrained hypertensive rats led to decreased relaxation responses in vessels with intact endothelium. Exercise training significantly improved the responses to acetylcholine and flow-mediated dilation in exercise-trained hypertensive rats in parallel with a decrease in blood pressure. On the other hand contraction (norepinephrine and KCl) and relaxation (sodium nitroprusside) responses of vascular smooth muscle were not different between the groups. Vascular endothelial NOS protein expression was found to be increased in both exercising groups. In conclusion, these results revealed evidence of an increased role of the nitric oxide-dependent relaxation pathway in exercising hypertensive rats.

The effect of aerobic physical training on cardiac autonomic control of rats submitted to ovariectomy

OBJECTIVE

To investigate the effect of aerobic physical training on cardiovascular autonomic control in ovariectomized rats using different approaches.

DESIGN

Female Wistar rats were divided into four groups: sedentary sham rats (group SSR), trained sham rats(group TSR), sedentary ovariectomized rats (group SOR), and trained ovariectomized rats (group TOR). Animals from the trained groups were submitted to a physical training protocol (swimming) for 12 weeks.

RESULTS

Pharmacological evaluation showed that animals from group TSR had an increase in their cardiac vagal tonus compared with the animals from groups SSR and SOR. The analysis of heart rate variability (HRV) showed that groups TSR and SOR had fewer low-frequency oscillations (0.20-0.75 Hz) compared with groups SSR and TOR.When groups TSR and SOR were compared, the former was found to have fewer oscillations. With regard to high frequency oscillations (0.75-2.5 Hz), group SSR had a reduction compared with the other groups, whereas group TSR had the greatest oscillation compared with groups SOR and TOR, with all values expressed in normalized units.Analysis of HRV was performed after pharmacological blockade, and low-frequency oscillations were found to be predominantly sympathetic in sedentary animals, whereas there was no predominance in trained animals.

CONCLUSION

Ovariectomy did not change the tonic autonomic control of the heart and, in addition, reduced the participation of sympathetic component in cardiac modulation. Physical training, on the other hand, increased the participation of parasympathetic modulation on the HRV, including ovariectomized rats.

Sport therapy for hypertension: why, how, and how much?

Exercise may prevent or reduce the effects of metabolic and cardiovascular diseases, including arterial hypertension. Both acute and chronic exercise, alone or combined with lifestyle modifications, decrease blood pressure and avoid or reduce the need for pharmacologic therapy in patients with hypertension. The hypotensive effect of exercise is observed in a large percentage of subjects, with differences due to age, sex, race, health conditions, parental history, and genetic factors. Exercise regulates autonomic nervous system activity, increases shear stress, improves nitric oxide production in endothelial cells and its bioavailability for vascular smooth muscle, up-regulates antioxidant enzymes. Endurance training is primarily effective, and resistance training can be combined with it. Low-to-moderate intensity training in sedentary patients with hypertension is necessary, and tailored programs make exercise safe and effective also in special populations. Supervised or home-based exercise programs allow a nonpharmacological reduction of hypertension and reduce risk factors, with possible beneficial effects on cardiovascular morbidity.

Effects of mild aerobic physical exercise on membrane fluidity of erythrocytes in essential hypertension

1. The present study was undertaken to investigate the effects of aerobic physical exercise on membrane function in mild essential hypertension. 2. Hypertensive patients were divided into an exercise group (n = 8) and a non-exercise (control) group (n = 8). Physical exercise within the intensity of the anaerobic threshold level was performed twice a week for 6 months. Membrane fluidity of erythrocytes was examined by means of electron paramagnetic resonance (EPR) and spin-labelling methods before and after the trial period in both groups. 3. After physical exercise, blood pressure decreased significantly. 4. Compared with the non-exercise group, in the exercise group both the order parameter (S) and the peak height ratio (ho/h-1) in the EPR spectra of erythrocytes were significantly reduced (S, 0.717 +/- 0.004 vs 0.691 +/- 0.008, respectively (n = 8), P < 0.05; ho/h-1, 5.38 +/- 0.06 vs 4.89 +/- 0.06, respectively (n = 8), P < 0.05). These findings indicated that exercise increased membrane fluidity and improved the membrane microviscosity of erythrocytes. 5. There was no direct correlation between blood pressure reduction and the exercise-induced increase in membrane fluidity of erythrocytes. 6. In the non-exercise (control) group, blood pressure and membrane fluidity were not changed after a 6 month follow-up period. 7. The results show that aerobic physical exercise increased erythrocyte membrane fluidity and improved the rigidity of cell membranes in hypertensive patients. The improvement of rheological properties of erythrocytes may explain, in part, the cellular mechanisms for the beneficial effects of physical exercise in hypertension.

Life-style and serum lipids and lipoproteins

In reviewing the trends and influences of life-style in this country on health and disease in the latter half of 20th century, we focused our attention on 4 major habits of smoking, drinking, exercise and diets, and collected data on the Japanese to conduct a meta-analysis of their relationship with serum lipids and lipoproteins, which are the metabolic risk factors most closely related to atherosclerosis. 1) The percentage of smokers was 54.0% in adult males and 14.5% in adult females in 1999. In the data of 7,256 subjects (mean age 47 years) in 16 papers, smoking increased triglycerides by 13 mg/dl (0.15 mmol/L) or in 559 non-drinkers with a mean age of 49 years in 3 papers by 18 mg/dl (0.20 mmol/L), and decreased HDL-cholesterol by 3.5 mg/dl (0.09 mmol/L) with every 20 cigarettes smoked according to the regression equation. 2) As for drinking, the annual ethanol consumption per adult was 8.5L in 1996. The effects of alcohol on serum lipids were analyzed in 27,035 males (mean age 47 years) in 24 studies. Drinking elevated triglycerides by a mean of 10 mg/dl (0.11 mmol/L), and also HDL-cholesterol by 2.5 mg/dl (0.06 mmol/L) per 23 g of alcohol intake (corresponding to 1 go of sake or 1 large bottle of beer). 3) Concerning exercise habit, 25% of males and 21% of females (mean age 47 years) regularly performed exercise such as jogging, swimming, aerobics, and tennis. However, walking was regarded as an easy exercise to be practiced by subjects of all ages. The effects of walking on serum lipids were studied in a total of 46,074 subjects (mean age 47 years) in 8 populations. Triglycerides were significantly lower by 10 mg/dl (0.11 mol/L), and HDL-cholesterol higher by 3 mg/dl (0.08 mmol/L) in those who walked 6,000 or more steps/day than in those who walked less than 2,000 steps/day. The effects of harder exercise like jogging or swimming were analyzed in 2,242 subjects in 14 papers (mean age 44 years). Triglycerides decreased by 10 mg/dl (0.11 mmol/L), and HDL-cholesterol elevated by 5 mg/dl (0.13 mmol/L) with an increase in the exercise intensity by one level of about 300 kcal. In exercise therapy, triglycerides were decreased by a mean of 20 mg/dl (0.23 mmol/L), and HDL cholesterol increased by a mean of 10 mg/dl (0.26 mmol/L) by exercise at a mean heart rate of about 135 bpm, which is equivalent to 50% VO2max for 30 minutes x 3 times/week. 4) In nutritional trends, the mean energy intake in 52 postwar years averaged 2,116+/-84 kcal with no marked changes according to nutritional surveys. However, the percentage of fat in total energy intake was lowest at 7% in 1946, increased thereafter until it exceeded 20% in 1973, and surpassed 25% in 1988. The mean total cholesterol level of the Japanese increased by 28 mg/dl (0.72 mmol/L) in the past 30 years and reached 204 mg/dl (5.28 mmol/L) in a survey in 1990. 5) Concerning dietary habits, total cholesterol was lower by a mean of 13 mg/dl (0.34 mmol/L), triglycerides lower by 40 mg/dl (0.45 mmol/L), and HDL-cholesterol higher by 5 mg/dl (0.13 mmol/L) in the group who ate 7 or more Japanese-style meals in the 9 meals during 3 days than in the group who ate 3 or less Japanese-style meals in the 9 meals. When serum lipids were compared among individuals living in cities (8 groups; 3,613 subjects; mean age 51 years), agricultural villages (13 groups; 5,364 subjects; mean age 51 years), and fishing villages (9 groups; 1,071 subjects; mean age 52 years). Total cholesterol was lower by a mean of 10 mg/dl (0.26 mmol/L) in fishing villages than in cities, and triglycerides lower by a mean of 15 mg/dl (0.17 mmol/L) in fishing villages than in cities and agricultural villages. HDL-cholesterol was 5 mg/dl (0.13 mmol/L) higher in agricultural villages and 3 mg/dl (0.08 mmol/L) higher in fishing villages than in cities. 6) The effects of dietary therapy or guidance were evaluated in 585 subjects (mean age, 53 years) in 12 papers. Total cholesterol was reduced by 20 mg/dl (0.52 mmol/L), triglycerides by a mean of 40 mg/dl (0.45 mmol/L), and HDL-cholesterol was increased by 5 mg/dl (0.13 mmol/L) by restriction of fat intake or restriction of the intake of saturated fat and dietary cholesterol. The results of these meta-analyses are considered to indicate the extent to which abnormalities of serum lipids are caused by a distorted life-style and the extent to which they are improved by correction of the life-style and exercise or dietary therapy. Correction of the life-style as a non-drug therapy may clearly improve hyperlipidemias or hypo-HDL-cholesterolemia so that this approach should be aggressively employed as part of the prevention and treatment for hyperlipidemias.

New evidence for the spasm-of-resistance-vessel concept of ischemic diseases

The spasm of resistance vessel (S-RV) concept of ischemic diseases avers that S-RV representing vascular autoregulatory dysfunction directly induces symptoms in ischemic diseases. The most important ischemic diseases, ischemic heart disease (IHD) and stroke, generally are not attributed to S-RV, and new evidence will be provided in this communication that S-RV induces IHD and stroke. Hypertension and the ischemic disorders of migraine and Raynaud's disease have been attributed to S-RV and to vascular dysregulation, and this information was used to help structure the study. It was found that these disorders are closely associated with IHD and stroke, and this is consistent with S-RV and vascular dysregulation as the mechanism for IHD and stroke. Also, it was found that multiple risk factors for IHD foster S-RV and are risk factors for hypertension, migraine, Raynaud's disease, and stroke, and this supports S-RV as the mechanism for IHD and stroke.

[The effects of low intensity aerobic training on the physiological indexes and the quality of life in middle-aged white collar workers]

The effects of short-term low intensity aerobic training on the physiological indexes and the Quality of Life were examined in 43 middle-aged White Collar Workers. Training was carried out for 205 +/- 117 minutes/week, at least 2-3 times/week for 2 months on a cycle ergometer or walking with intensity level set at the 50% VO2max. Following this training protocol, thirty-six men (exercise group) completed the 2-month training program and 7 men dropped out (the dropout group). In the exercise group, both the VO2max (l/min) and VO2max/wt increased significantly (VO2max (l/min): P < 0.05. VO2max/wt: P < 0.01), whereas the weight, body mass index, %fat, fat (kg) and the waist hip ratio (WHR) decreased significantly (WHR: P < 0.05, others: P < 0.01) after 2 months. In addition, the DBP and serum TC, LDL-c/HDL-c decreased significantly (LDL-c/HDL-c: P < 0.01, others: P < 0.05) whereas the HDL-c increased significantly (P < 0.05). A modified Croog questionnaire was used to assess the subject's Quality of Life. The questionnaire consisted of 59 questions and the overall assessment was based on eight components. Regarding the Quality of Life, physical symptoms, work performance and satisfaction, total Quality of Life all improved significantly (physical symptoms, P < 0.05; others: P < 0.01) and social participation also tended to improve (P < 0.08). There was a significantly negative correlation between the initial Quality of Life and the changes in the Quality of Life (6 of the 8 components). In the all subjects, there was a significantly positive correlation between the changes in physical symptoms and the changes in VO2max/wt (r = 0.36, P < 0.05). In the dropout group, the FBS increased significantly (P < 0.05) but no other variables regarding the Quality of Life significantly changed after 2 months. In conclusion the above results suggest that short-term low intensity aerobic training in the present study can help improve the physiological indexes, VO2max and Quality of Life in middle-aged White Collar Workers and the observed improvement in the Quality of Life was also found to be greater in the subjects with a low Quality of Life than in those with a high Quality of Life.

Training in swimming reduces blood pressure and increases muscle glucose transport activity as well as GLUT4 contents in stroke-prone spontaneously hypertensive rats

Exercise improves muscle insulin sensitivity and GLUT4 contents. We investigated the beneficial effects of swimming training on insulin sensitivity and genetic hypertension using stroke-prone hypertensive rats (SHRSP). We studied the relationship between genetic hypertension and insulin resistance in SHRSP and Wistar Kyoto rats (WKY) as a control. The systolic blood pressure of SHRSP was significantly reduced by 4-week swimming training (208.4 +/- 6.8 mmHg vs. 187.2 +/- 4.1 mmHg, p < 0.05). The swimming training also resulted in an approximately 20% increase in the insulin-stimulated glucose transport activity (p < 0.05) of soleus muscle strips and an approximately 3-fold increase in the plasma membrane GLUT4 protein expression (p < 0.01) in SHRSP. However, basal and insulin-stimulated glucose transport activity and GLUT4 contents were not significantly different between WKY and SHRSP. There was no difference in insulin resistance in skeletal muscle of SHRSP as compared with WKY. Our results indicated swimming training exercise improved not only hypertension but also muscle insulin sensitivity and GLUT4 protein expression in SHRSP.

Blood pressure lowering effect of low intensity aerobic training in elderly hypertensive patients

PURPOSE

The purpose of this investigation was to determine the effect of 9 months of low intensity aerobic training on blood pressure in elderly hypertensive patients who were receiving antihypertensive medication.

METHODS

The training group (N = 13; mean age 75.4 +/- 5.4 yr) agreed to take part in physical training using a treadmill with an exercise intensity at the blood lactate threshold (LT) for 30 min three to six times a week for 9 months. The rest (N = 13; mean age 73.1 +/- 4.2 yr) served as controls.

RESULTS

The resting systolic (-15 +/- 8 mm Hg), mean (-11 +/- 6 mm Hg), and diastolic blood pressures (-9 +/- 9 mm Hg) decreased significantly after 3 months of training and the blood pressure of all participants stabilized at a significantly lower level by the end of the study (9 months) in the training group, whereas no significant changes in blood pressure were found in the control group. Both the pretraining systolic and diastolic blood pressure of those recruited patients negatively correlated with those changes after the training (SBP: P < 0.01; DBP: P < 0.05, respectively). After 1 month of detraining in five patients, the blood pressure levels were similar to those in the pretraining state. The LT increased significantly in the training group (P < 0.01).

CONCLUSION

In conclusion, an additional antihypertensive effect of mild aerobic training at the LT was confirmed in elderly patients receiving antihypertensive medication. The cessation of such training in five patients, however, resulted in a relatively rapid return to pretraining levels within a month.

Preliminary assessment of potential health hazards associated with barium leached from glazed ceramicware

Ceramic glazes contain several elements which have the potential to leach into food or beverages that are held or stored in ceramicware. Recently, barium salts have been investigated as one of the alternatives to lead in frit formulations for glazes. This preliminary evaluation addresses the potential health hazards associated with barium at levels that might leach from glazed ceramicware. A set of specialty ceramicware, consisting of five teacups and a pitcher, was examined for extractable barium. Exposure to barium that adults (18-44 years) might encounter using the vessels for coffee, tea, or orange juice was estimated. The exposure estimate was derived from values for intakes of the beverages and for the barium migration from glazed ceramicware test samples. An established reference dose (RfD) for barium exposure for the critical effect of hypertension was identified. The potential hazard associated with the leaching of barium from glazed ceramicware varied with the level of use. Consuming beverages in amounts up to the 95th percentile would not result in total barium intake in amounts that exceed the RfD; consuming large quantities (> 95th percentile) of beverages such as tea or coffee from glazed vessels might. This suggests that for a small portion of the population of users, intake of barium may be in quantities that warrant further consideration as a potential health hazard. Analyses of a broad sample of ceramicware and study of barium leaching behaviour under actual use conditions are needed to assess further the significance of these findings.

Vasodepressor effects of exercise are accompanied by reduced circulating ouabainlike immunoreactivity and normalization of nitric oxide synthesis

Our object was to evaluate the effects of regular mild exercise on blood pressure and on circulating level of ouabainlike factors (OLF) and of nitrate anion, an endproduct of nitric oxide (NO) in humans. We measured plasma ouabainlike immunoreactivity (OLI) and nitrate ions (NO3.) before and after mild exercise for 3 months' duration in 16 patients with essential hypertension, diabetes mellitus, obesity, or hyperlipidemia. Plasma OLI was measured using an amplified ELISA system with anti-ouabain antibody and biotinyl-tyramide. Serum NO3. was measured with high-performance liquid chromatography (HPLC) with an anion-exchange column. With the reverse phase HPLC system with an octa decylsilyl silicagel column, the elution volume of plasma OLI of a healthy volunteer matched that of authentic ouabain in a gradient elution system of acetonitrile/H2O. Plasma OLI levels decreased significantly by about 34% after mild exercise, and NO3. levels tended to be within the reference interval in normal volunteers. Body weight, diastolic and systolic blood pressure, serum triglyceride and acetylcholine esterase (a marker of the fatty liver) were significantly decreased (p < 0.01) after 3 months of regular mild exercise. The plasma OLI level was significantly correlated with plasma NO3., there was a trend toward a correlation with diastolic blood pressure (p = 0.06) before and after regular exercise. Regular mild exercise led to a decrease in plasma levels of OLI, and acetylcholine esterase activity and blood pressure in adult patients. Results suggest that changes in OLF production contribute to the blood pressure regulation seen in patients who exercise regularly.

Lifestyle modifications for hypertension. The many benefits are worth the effort

Any approach to antihypertensive therapy should include lifestyle modifications. In the beginning, emphasis should be on weight loss and exercise, along with moderation of alcohol use and cessation of smoking. Patients should be encouraged to consume fresh rather than processed (and thus high-salt) foods and to limit use of salt in cooking and at the table. Even if patients eventually require antihypertensive medications, lifestyle modifications should continue, since there is evidence that such measures minimize the number and dose of medications required.