Blood lipid and lipoprotein adaptations to exercise: a quantitative analysis

Combination diet and exercise interventions for the treatment of dyslipidemia: an effective preliminary strategy to lower cholesterol levels?

At present, dyslipidemia is most commonly treated with drug therapy. However, because safety concerns regarding the use of pharmaceutical agents have arisen, a need for alternative nonpharmacological therapies has become increasingly apparent. The National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) recommends lifestyle therapies, which include a combination of diet and exercise modifications, in place of drug treatment for patients who fall into an intermediate range of coronary heart disease (CHD) risk. This review examined the cholesterol lowering efficacy of the following 2 NCEP-recommended combination therapies: 1) low saturated fat diets combined with exercise, and 2) nutritional supplementation, i.e., fish oil, oat bran, or plant sterol supplementation, combined with exercise, in the treatment of dyslipidemia. Combination therapies are particularly advantageous because diet and exercise elicit complementary effects on lipid profiles. More specifically, diet therapies, with some exceptions, lower total (TC) and LDL cholesterol (LDL-C) concentrations, whereas exercise interventions increase HDL cholesterol (HDL-C) while decreasing triglyceride (TG) levels. With respect to specific interventions, low saturated fat diets combined with exercise lowered TC, LDL-C, and TG concentrations by 7-18, 7-15, and 4-18%, respectively, while increasing HDL-C levels by 5-14%. Alternatively, nutritional supplements combined with exercise, decreased TC, LDL-C, and TG concentrations by 8-26, 8-30, and 12-39%, respectively, while increasing HDL-C levels by 2-8%. These findings suggest that combination lifestyle therapies are an efficacious, preliminary means of improving cholesterol levels in those diagnosed with dyslipidemia, and should be implemented in place of drug therapy when cholesterol levels fall just above the normal range.

Prevalence of physical activity among Chinese adults: results from the International Collaborative Study of Cardiovascular Disease in Asia

OBJECTIVES

Determining physical activity levels in the community provides a context for the development and implementation of programs aimed at increasing these activity levels. Therefore, we assessed overall, work-related, and leisure-time physical activity in a representative sample of Chinese adults, aged 35 to 74 years, using data from the International Collaborative Study of Cardiovascular Disease in Asia.

METHODS

Being physically active was defined as participating in 30 or more minutes of moderate or vigorous activity daily. Work-related and leisure-time physical activities were defined as being physically active and participating in any moderate or vigorous activity at work or during leisure time, respectively.

RESULTS

In rural and urban China, 78.1% and 21.8% of residents, respectively, were physically active; 75.8% and 16.5%, respectively, participated in work-related activity; and 28.9% and 7.9%, respectively, participated in leisure-time physical activity. In both rural and urban settings, younger adults, men, and southern residents were more likely to be physically active and to participate in work-related and leisure-time physical activity than older adults, women, and northern residents.

CONCLUSIONS

Intervention strategies to promote leisure-time physical activity, especially among urban residents, should be considered a major health priority in China.

The effects of 60 minutes of brisk walking per week, accumulated in two different patterns, on cardiovascular risk

BACKGROUND

Current ACSM guidelines recommend that adults should exercise for 20-60 min on 3-5 days.week(-1) (M.L. Pollock, et al., The recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness, and flexibility in healthy adults. Medicine and Science in Sports and Exercise, 30 (6) (1998) 975-991.). For individuals constrained by a busy lifestyle, an exercise prescription that delivers benefits with the minimum investment of time is attractive. The purpose of the present study, therefore, was to examine the effect of instructing sedentary individuals to undertake 20 min of brisk walking, in two different patterns, 3 days per week, on fitness and other cardiovascular disease (CVD) risk factors.

METHODS

Forty-eight subjects (31 women) mean (+/-SD) age 45.7 +/- 9.4 year were randomly assigned to either one 20-min walk (single bout), two 10-min walks (accumulated bouts) 3 days week(-1) for 12-week, or no training (control). Oxygen consumption (VO2), heart rate (HR), and ratings of perceived exertion (RPE) were measured during a 4-stage treadmill test at pre- and post-intervention. Body composition, resting blood pressure and fasting lipoproteins were also assessed. Thirty-two subjects completed the study.

RESULTS

There was a significant difference between single-bout and accumulated-bout walkers in the reduction of HR at stages 2 and 3 of the treadmill test from pre- to post-intervention (P < 0.05). There were no differences between groups for changes in VO2 or RPE from pre- to post-intervention. There were also no changes in body mass, adiposity, blood pressure, waist and hip circumferences, or lipid/lipoproteins.

CONCLUSION

Brisk walking for 20 min on 3 days of the week fails to alter cardiovascular disease risk factors in previously sedentary adults.

Cardiac rehabilitation and secondary prevention of coronary heart disease: an American Heart Association scientific statement from the Council on Clinical Cardiology (Subcommittee on Exercise, Cardiac Rehabilitation, and Prevention) and the Council on Nutrition, Physical Activity, and Metabolism (Subcommittee on Physical Activity), in collaboration with the American association of Cardiovascular and Pulmonary Rehabilitation

This article updates the 1994 American Heart Association scientific statement on cardiac rehabilitation. It provides a review of recommended components for an effective cardiac rehabilitation/secondary prevention program, alternative ways to deliver these services, recommended future research directions, and the rationale for each component of the rehabilitation/secondary prevention program, with emphasis on the exercise training component.

Effects of exercise on the fatty-acid composition of blood and tissue lipids

This article reviews the effects of acute and chronic exercise on the fatty-acid composition of animal and human tissues (plasma, skeletal muscle, heart, adipose tissue, liver, artery and erythrocytes), as reported in 68 studies spanning four decades. The most consistently observed effect has been an increase in the relative amount of unsaturated, especially monounsaturated, non-esterified fatty acids in plasma of both animals and humans after acute exercise. Chronic exercise seems to increase the proportion of polyunsaturated fatty acids and omega6 fatty acids, while decreasing the proportion of monounsaturated fatty acids in animal and human adipose tissue. Additionally, chronic exercise seems to decrease the relative amount of unsaturated fatty acids in liver lipids of animals and humans. There is no consensus regarding the effect of exercise on the fatty-acid composition of lipids in any other tissue. In general, the effects of exercise are independent of nutrition and, regarding skeletal muscle, muscle fibre type. The available literature shows that, in addition to modifying the concentrations of animal and human tissue lipids, exercise also changes their fatty-acid profile. Unfortunately, the available studies are so much divided among exercise models, species and biological samples that a cohesive picture of the plasticity of the fatty-acid pattern of most tissues toward exercise has not emerged. Future studies should focus on determining the fatty-acid profile of separate lipid classes (rather than total lipids) in separate subcellular fractions (rather than whole tissues), examining tissues and organs on which no data are available and exploring the mechanisms of the exercise-induced changes in fatty-acid composition.

Position related analysis of the appearance of and relationship between post-match physical and mental fatigue in university rugby football players

OBJECTIVE

The relationship between physical and mental fatigue in rugby players after a match was examined, taking into account the position played.

METHODS

The Profile of Mood State (POMS) test, blood biochemical parameters, and serum opsonic activity were measured for 37 university rugby football players before and after a match.

RESULTS

There were no differences in parameter changes except for blood urea nitrogen (a marker for protein catabolism) between the forwards and the backs. Regarding correlation between physical and mental fatigue, in forwards, changes in POMS scores showed a positive correlation with changes in the levels of enzymes of skeletal muscle origin, such as glutamate oxaloacetic transaminase (GOT) and lactate dehydrogenase (LDH), and free fatty acid (FFA) level and white blood cell count (for example, in the Total Mood Disturbance (TMD) score, Spearman's correlation coefficient was 0.417 and p<0.05 with GOT, 0.413 and p<0.05 with LDH, 0.462 and p<0.05 with FFA, and 0.442 and p<0.05 with white blood cell count). In backs, changes in the POMS scores showed a positive correlation with changes in the levels of lipid related parameters such as FFA and total cholesterol (for example, as regards the TMD score, Spearman's correlation coefficient was 0.481 and p<0.05 with FFA, and 0.550 and p<0.05 with total cholesterol), and showed a negative correlation with change in blood glucose level (TMD score, -0.517 and p<0.05).

CONCLUSIONS

The different exercise loading of the position played during a rugby match may cause differences in the relationship between physical and mental fatigue.

[Blood pressure, heart rate and lipids in professional handball and water polo players]

INTRODUCTION

Blood pressure, heart rate and lipoprotein lipids are affected by family history, obesity, diet, smoking and physical activity habits. The aim of this paper was to estimate the values of blood pressure and heart rate in professional handball and water polo players before and after training and submaximal exercise test and to analyze the lipid state in these professional athletes in comparison with people who have never been in sports.

MATERIAL AND METHODS

The investigation included 30 professional handball players, 30 professional water polo players and 15 men who have never been in sports (control group). All groups were matched for age, smoking habits, family predisposition to arterial hypertension and dyslipidemia.

RESULTS

Between these groups there were statistically significant differences of blood pressure values and heart rate in the state of rest, after exercise test and after the training. There were also statistically significant differences of total cholesterol values, LDL cholesterol, triglycerides, HDL cholesterol, LDL cholesterol/HDL cholesterol ratio and total cholesterol/HDL ratio between these groups.

DISCUSSION

Differences between these groups can be explained by various values of body mass index, by activity of lipoprotein lipase in athletes, by body position during the sports activity, by thermoregulatory vasoconstriction in the water, and by effects of hydrostatic pressure and reflex mechanisms during swimming.

CONCLUSIONS

Cardiovascular reaction in professional athletes depends on the type of sports activity, body position and medium during training. Professional athletes have a lower atherogenic risk than non-sportsmen. Changes of blood pressure and heart rate after submaximal exercise test are not the same as changes after training.

Changes in cardiorespiratory fitness and coronary heart disease risk factors following 24 wk of moderate- or high-intensity exercise of equal energy cost

This study was designed to investigate the effect of exercise intensity on cardiorespiratory fitness and coronary heart disease risk factors. Maximum oxygen consumption (Vo(2 max)), lipid, lipoprotein, and fibrinogen concentrations were measured in 64 previously sedentary men before random allocation to a nonexercise control group, a moderate-intensity exercise group (three 400-kcal sessions per week at 60% of Vo(2 max)), or a high-intensity exercise group (three 400-kcal sessions per week at 80% of Vo(2 max)). Subjects were instructed to maintain their normal dietary habits, and training heart rates were represcribed after monthly fitness tests. Forty-two men finished the study. After 24 wk, Vo(2 max) increased by 0.38 +/- 0.14 l/min in the moderate-intensity group and by 0.55 +/- 0.27 l/min in the high-intensity group. Repeated-measures analysis of variance identified a significant interaction between monthly Vo(2 max) score and exercise group (F = 3.37, P < 0.05), indicating that Vo(2 max) responded differently to moderate- and high-intensity exercise. Trend analysis showed that total cholesterol, low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol, and fibrinogen concentrations changed favorably across control, moderate-intensity, and high-intensity groups. However, significant changes in total cholesterol (-0.55 +/- 0.81 mmol/l), low-density lipoprotein cholesterol (-0.52 +/- 0.80 mmol/l), and non-high-density lipoprotein cholesterol (-0.54 +/- 0.86 mmol/l) were only observed in the high-intensity group (all P < 0.05 vs. controls). These data suggest that high-intensity training is more effective in improving cardiorespiratory fitness than moderate-intensity training of equal energy cost. These data also suggest that changes in coronary heart disease risk factors are influenced by exercise intensity.

What is the relationship between exercise and metabolic abnormalities? A review of the metabolic syndrome

Prevention of the metabolic syndrome and treatment of its main characteristics are now considered of utmost importance in order to combat the epidemic of type 2 diabetes mellitus and to reduce the increased risk of cardiovascular disease and all-cause mortality. Insulin resistance/hyperinsulinaemia are consistently linked with a clustering of multiple clinical and subclinical metabolic risk factors. It is now widely recognised that obesity (especially abdominal fat accumulation), hyperglycaemia, dyslipidaemia and hypertension are common metabolic traits that, concurrently, constitute the distinctive insulin resistance or metabolic syndrome. Cross-sectional and prospective data provide an emerging picture of associations of both physical activity habits and cardiorespiratory fitness with the metabolic syndrome. The metabolic syndrome, is a disorder that requires aggressive multi-factorial intervention. Recent treatment guidelines have emphasised the clinical utility of diagnosis and an important treatment role for 'therapeutic lifestyle change', incorporating moderate physical activity. Several previous narrative reviews have considered exercise training as an effective treatment for insulin resistance and other components of the syndrome. However, the evidence cited has been less consistent for exercise training effects on several metabolic syndrome variables, unless combined with appropriate dietary modifications to achieve weight loss. Recently published randomised controlled trial data concerning the effects of exercise training on separate metabolic syndrome traits are evaluated within this review. Novel systematic review and meta-analysis evidence is presented indicating that supervised, long-term, moderate to moderately vigorous intensity exercise training, in the absence of therapeutic weight loss, improves the dyslipidaemic profile by raising high density lipoprotein-cholesterol and lowering triglycerides in overweight and obese adults with characteristics of the metabolic syndrome. Lifestyle interventions, including exercise and dietary-induced weight loss may improve insulin resistance and glucose tolerance in obesity states and are highly effective in preventing or delaying the onset of type 2 diabetes in individuals with impaired glucose regulation. Randomised controlled trial evidence also indicates that exercise training decreases blood pressure in overweight/obese individuals with high normal blood pressure and hypertension. These evidence-based findings continue to support recommendations that supervised or partially supervised exercise training is an important initial adjunctive step in the treatment of individuals with the metabolic syndrome. Exercise training should be considered an essential part of 'therapeutic lifestyle change' and may concurrently improve insulin resistance and the entire cluster of metabolic risk factors.

Healthy aging: health promotion and disease prevention

Successful aging includes the ability to perform functional tasks. This ability to perform functional tasks, or functional ability, is influenced by musculoskeletal and cardiovascular functioning and the presence and severity of symptoms of chronic disease. Empirical evidence indicates that musculoskleletal and cardiovascular functioning and symptoms of chronic disease in later life are strongly related to lifestyle choices involving physical activity and nutritional intake. Previous researchers have demonstrated that increases in physical activity and appropriate changes in nutritional intake can be effective interventions to prevent and treat symptoms of chronic disease and improve musculoskeletal and cardiovascular functioning. As a result of this evidence, several organizations have developed physical activity and nutritional intake recommendations aimed at maintaining or increasing the functional ability of older adults. These physical activity recommendations include engaging in cardiorespiratory, flexibility, strength, and balance training 3 to 5 days per week. Broad nutritional recommendations for older adults include a low-fat, plant-based diet including fruits, vegetables, whole grains, 8 glasses of water per day, and a vitamin and mineral supplement.

Physical Fitness and Reverse Cholesterol Transport

BACKGROUND

Physical exercise is associated with a decreased risk of cardiovascular disease, which may be partly caused by the effect of exercise on the lipoprotein profile. The most consistent effect of exercise on lipoprotein metabolism is an increase in high-density lipoprotein (HDL).

METHODS AND RESULTS

Parameters of reverse cholesterol transport (RCT) in 25 endurance-trained male athletes were compared with 33 age-matched males enjoying an active lifestyle. VO2max was higher in athletes than in controls (53.4+/-1.2 versus 38.8+/-1.0 mL/min per kg; P<0.01). The following differences in parameters of RCT were found: (1) plasma HDL cholesterol and apoA-I levels were higher in athletes compared with controls (1.7+/-0.1 versus 1.4+/-0.1 mmol/L; P<0.001; and 145+/-2 versus 128+/-3 mg/dL; P<0.001, respectively). Both correlated with VO2max up to the value of 51 mL/min per kg; (2) prebeta1-HDL was higher in athletes than in controls (54+/-4 versus 37+/-3 microg/mL; P<0.001) and correlated positively with VO2max; (3) lecithin cholesterol: acyltransferase activity was higher in athletes (29.8+/-1.2 versus 24.2+/-1.4 nmol/microL per hour; P<0.005); and (4) the capacity of plasma to promote cholesterol efflux from macrophages was higher in athletes (18.8%+/-0.8% versus 16.2%+/-0.3%; P<0.03).

CONCLUSIONS

The likely reason for higher HDL concentration in physically fit people is increased formation of HDL from apoA-I and cellular lipids.

Effects of exercise on the physical condition of college rugby players during summer training camp

OBJECTIVES

To determine the effects of exercise training on physical condition in 25 college rugby players during a summer training camp, and to compare these variables by the different players' positions.

METHODS

Changes in body composition parameters and blood biochemistry were examined before and after a summer training camp.

RESULTS

Body weight and percentage body fat did not change significantly during the camp. There were significant decreases in levels of serum total cholesterol, triglycerides, phosphate, uric acid, and immunoglobulin G and M. In contrast, there were significant increases in levels of serum potassium, markers of renal, hepatic, and muscular damage (BUN, GOT, GPT, LDH, CK), and complement C4. Comparison of the changes in biochemical parameters between rugby players playing in different positions showed a significant increase in serum albumin level in the forwards, and significant decreases in serum triglyceride and sodium levels in the backs. The magnitude of change in serum LDH during the camp was significantly greater (p<0.05) for the forwards than for the backs.

CONCLUSIONS

These data suggest that, in rugby players attending a 20 day camp, exercise training resulted in muscular damage, loss of electrolytes due to sweating, and changes in immune function. Backs exhibited a higher rate of fat metabolism and loss of electrolytes than forwards, possibly because they did more running during the camp. In contrast, forwards experienced more physical contact, performed more physically strenuous exercise, and exhibited higher levels of muscular damage and tissue protein degradation.

Targeting the metabolic syndrome with exercise: evidence from the HERITAGE Family Study

PURPOSE

To determine the efficacy of exercise training in treating the metabolic syndrome.

METHODS

The sample included 621 black and white participants from the HERITAGE Family Study, identified as sedentary and apparently healthy (no chronic disease or injury). The metabolic syndrome was defined as having three or more risk factors according to the guidelines of the National Cholesterol Education Program, including elevated waist circumference, blood pressure, triglycerides, blood glucose, and low HDL cholesterol. The presence of the metabolic syndrome and component risk factors were determined before and after 20 wk of supervised aerobic exercise training.

RESULTS

The prevalence of the metabolic syndrome was 16.9% in this sample (105/621) of apparently healthy participants. Of the 105 participants with the metabolic syndrome at baseline, 30.5% (32 participants) were no longer classified as having the metabolic syndrome after the exercise training. Among the 32 participants who improved their metabolic profile, 43% decreased triglycerides, 16% improved HDL cholesterol, 38% decreased blood pressure, 9% improved fasting plasma glucose, and 28% decreased their waist circumference. There were no sex or race differences in the efficacy of exercise in treating the metabolic syndrome: 32.7% of men, 28.0% of women, 29.7% of black, and 30.9% of white participants with the metabolic syndrome were no longer classified as having the syndrome after training.

CONCLUSION

Aerobic exercise training in patients with the metabolic syndrome can be useful as a treatment strategy and provides support for a role for physical activity in the prevention of chronic disease.

Blood lipids of cardiac patients after acute exercise on land and in water

OBJECTIVE

To compare the effect on lipids of a single bout of high-intensity interval training performed on land and in water in a group of cardiac patients involved in an intensive cardiac rehabilitation program.

DESIGN

Single-group, quasiexperimental, crossover design.

SETTING

Swimming pool at a cardiac rehabilitation hospital in Australia.

PARTICIPANTS

Ten men, ages 55 to 77 years, with ischemic heart disease.

INTERVENTION

Subjects performed 15 minutes of interval arm ergometer work at 65% to 75% of attained heart rate, as determined by treadmill testing on land and in water on the same day. Each patient had his own exercise prescription.

MAIN OUTCOME MEASURES

At each endurance phase, the number of revolutions and rate-pressure product (RPP) during the final minute of work were taken. Fasting bloods were taken at baseline and after maximum exercise, and lipid profiles were determined; differences were analyzed by paired t test.

RESULTS

No significant differences in revolutions or RPP were observed, which indicates that workload and heart work were similar in all experiments. There were no significant changes in total, low-density lipoprotein cholesterol, triglyceride, or apolipoproteins A-I or B after exercise (paired t test). High-density lipoprotein cholesterol (HDL-C) was increased significantly by exercise on land. In 6 patients with low baseline HDL-C (<0.9 mmol/L), HDL-C was increased only on land.

CONCLUSIONS

A single bout of high-intensity interval training was more effective in improving HDL-C when performed on land than in water.

Lifestyle determinants of high-density lipoprotein cholesterol: the National Heart, Lung, and Blood Institute Family Heart Study

BACKGROUND

While genetic factors are major determinants of high-density lipoprotein cholesterol (HDL-C), environmental factors also play a role. The latter include 3 modifiable lifestyle factors: alcohol consumption, physical activity, and smoking.

METHODS

We compared the relative effects of alcohol, physical activity, and smoking on HDL-C levels, using data from 2309 subjects (1226 women and 1083 men), aged 25 to 91 years, from randomly selected families participating in the National Heart, Lung, and Blood Institute Family Heart Study.

RESULTS

Alcohol consumption was associated with the largest increment in HDL-C (an increase of 9.0-13.1 mg/dL from nondrinker to highest categories); physical activity with a more modest increment (an increase of 3.0-3.3 mg/dL from lowest to highest categories); and cigarette smoking with a large decrement in women (a decrease of 9.9 mg/dL) and a modest one in men (a decrease of 2.6 mg/dL) between nonsmoker and > or =20 cigarettes per day categories. The 3 lifestyle behaviors plus age, body mass index, education, and current estrogen use explained 22.4% and 18.2% of the total variance of HDL-C for women and men, respectively. Alcohol accounted for 28.6% of this variance among women and 50.1% among men; smoking accounted for 6.7% and 3.3%, respectively, and physical activity for 2.7% and 3.6%, respectively, among women and men. Age, body mass index, education, and current estrogen use explained the remaining 62.0% and 43.0%, respectively, of the variance attributed to environmental factors.

CONCLUSIONS

This study suggests that, among lifestyle behaviors, alcohol consumption is the more important correlate of HDL-cholesterol.

Physical activity and its effects on lipids

Physical activity is an important component of weight control, and is widely recommended to prevent and treat obesity-related complications such as diabetes and coronary heart disease (CHD). Although the cardiovascular benefits of increased physical activity are likely multifactorial, much of the attention has been focused on the known high-density lipoprotein (HDL) cholesterol-raising properties of regular physical activity. Physical activity, however, can also reliably lower triglycerides and favorably affect both low-density lipoprotein (LDL) and HDL particle sizes. Limited data on resistance exercise suggest that this type of physical activity may reduce LDL cholesterol. Although these lipid effects are modest and variable, they are likely to be particularly important in reducing the morbidity and mortality from CHD on a population level, and may be especially important in patients with atherogenic dyslipidemia.

HIV Lipodystrophy Syndrome: A Primer

Treatment with highly active antiretroviral therapy (HAART) has been implicated in the development of anthropomorphic and metabolic abnormalities termed HIV lipodystrophy syndrome (or LDS). This primer offers a comprehensive overview of LDS including epidemiology, hypothesized etiologies, and clinical consequences. The evidence-based literature is reviewed for current treatment strategies including discontinuation of specific antiretrovirals, pharmacological management of dyslipidemia and insulin resistance, exercise training, facial augmentation, liposuction, and hormonal therapy. Patient education, counseling, and adherence are discussed.

Effects of creatine supplementation and exercise training on fitness in men 55-75 yr old

effect of oral creatine supplementation (CR; 5 g/day) in conjunction with exercise training on physical fitness was investigated in men between 55 and 75 yr of age (n = 46). A double-blind randomized placebo-controlled (PL) trial was performed over a 6-mo period. Furthermore, a subgroup (n = 20) completed a 1-yr follow-up. The training program consisted of cardiorespiratory endurance training as well as moderate resistance training (2-3 sessions/wk). Endurance capacity was evaluated during a maximal incremental bicycle ergometer test, maximal isometric strength of the knee-extensor muscles was assessed by an isokinetic dynamometer, and body composition was assessed by hydrostatic weighing. Furthermore, in a subgroup (PL: n = 13; CR: n = 12) biopsies were taken from m. vastus lateralis to determine total creatine (TCr) content. In PL, 6 mo of training increased peak oxygen uptake rate (+16%; P < 0.05). Fat-free mass slightly increased (+0.3 kg; P < 0.05), whereas percent body fat slightly decreased (-1.2%; P < 0.05). The training intervention did not significantly change either maximal isometric strength or body weight. The responses were independent of CR. Still, compared with PL, TCr was increased by approximately 5% in CR, and this increase was closely correlated with initial muscle creatine content (r = -0.78; P < 0.05). After a 1-yr follow-up, muscle TCr was not higher in CR than in PL. Furthermore, the other measurements were not affected by CR. It is concluded that long-term creatine intake (5 g/day) in conjunction with exercise training does not beneficially impact physical fitness in men between 55 and 75 yr of age.

Obesity-associated activation of angiotensin and endothelin in the cardiovascular system

The renin-angiotensin system (RAS) and the endothelin system have been implicated in the pathogenesis of human cardiovascular and renal diseases, and inhibition of the RAS markedly improves morbidity and survival. Obesity in humans is associated with an increased risk for the development of hypertension, atherosclerosis and focal-segmental glomerulosclerosis, however the exact mechanisms underlying these pathologies in obese individuals are not known. This article discusses the clinical importance of obesity and the current evidence for local activation of the renin-angiotensin system and its interactions with the endothelin system in obesity and the cardiovascular pathologies associated with it.

Impact of the Pro12Ala polymorphism of the PPAR-gamma2 gene on serum triacylglycerol response to n-3 fatty acid supplementation

Serum lipid responses to dietary modification are partly determined by genetic factors. The objective of the present study was to investigate the influence of the Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-gamma2 (PPAR-gamma2) gene on serum lipid and lipoprotein responses to n-3 fatty acid supplementation. A total of 76 men and 74 women (age 49+/-8 years, body mass index 26.5+/-3.0 kg/m(2)) participated in a controlled multi-center study. Subjects were randomly assigned to consume either fish oil supplements (3.6g n-3 fatty acids/day containing 2.4 g of EPA and DHA) or placebo capsules containing olive oil for 3 months. At baseline, the Pro12Ala polymorphism was not associated with serum total and lipoprotein lipid concentrations or lipoprotein lipase activity in the fasting state. After the 3-month study period, carriers of the Ala12 allele presented a greater decrease in serum triacylglycerol concentration in response to n-3 fatty acid supplementation than did subjects with the Pro12Pro genotype when the total dietary fat intake was below 37 E% (p=0.003) or the intake of saturated fatty acids was below 10 E% (p=0.006). Changes in serum total cholesterol, serum LDL cholesterol and HDL cholesterol concentrations were similar among the genotypes in the n-3 fatty acid supplementation group and in the placebo group. In conclusion, the Pro12Ala polymorphism of the PPAR-gamma2 gene may modify the inter-individual variability in serum triacylglycerol response to n-3 fatty acid supplementation.

National Cholesterol Education Program: Adult Treatment Panel III--new recommendations for lifestyle and medical management of dyslipidemia

In the 1990s a number of randomized controlled trials provided compelling evidence for the importance of aggressively managing hypercholesterolemia. Control of low-density lipoprotein cholesterol reduces cardiac events and stroke in at risk individuals without known cardiac disease and in patients with coronary heart disease. The National Cholesterol Education Program Adult Treatment Panel has published 3 sets of guidelines. The most recent expanded definitions of those at risk by defining new risk categories and increased the numbers of persons who could benefit from more intensive cholesterol-lowering. These new definitions moved millions of people into more intensive treatment categories compared to previously published guidelines. This article focuses on the latest National Cholesterol Education Program guidelines for identification and treatment of persons with or at risk for coronary heart disease.

Single session exercise stimulates formation of pre beta 1-HDL in leg muscle

Physical activity can raise the level of circulating HDL cholesterol. Pre beta 1-HDL is thought to be either the initial acceptor of cellular cholesterol or virtually the first particle in the pathway of the formation of HDL from apolipoprotein A-I and cellular lipids. We have therefore sought to identify pre beta 1-HDL in arterial and venous circulations of exercising legs in healthy individuals and in subjects with stable Type 2 diabetes mellitus. Blood samples were taken simultaneously from the femoral artery and vein before and after 25 min cycling exercise. The major findings were, first, that exercise significantly increased plasma concentration of pre beta 1-HDL (20% increase, P < 0.05) and second, that the pre beta 1-HDL concentration was significantly higher in the venous compared with the arterial blood both before and after exercise in both diabetics and controls. In the combined population, formation of pre beta 1-HDL at rest was 9.9 +/- 5.2 mg/min and exercise enhanced pre beta 1-HDL formation 6.6-fold in both groups.

Lifestyle intervention of hypocaloric dieting and walking reduces abdominal obesity and improves coronary heart disease risk factors in obese, postmenopausal, African-American and Caucasian women

BACKGROUND

There are few empirical data to support the claim that weight loss improves coronary heart disease (CHD) risk factors in postmenopausal women; nor is it known if there are racial differences in changes of body fat distribution, lipids, glucose tolerance, and blood pressure with weight loss. This study determined the efficacy of a lifestyle weight loss intervention in reducing total and abdominal obesity and improving CHD risk factors in obese Caucasian and African-American postmenopausal women.

METHODS

Body composition (dual-energy x-ray absorptiometry), abdominal fat areas (computed tomography scan), lipoprotein lipids, insulin, glucose tolerance, and blood pressure were measured before and after 6 months of hypocaloric diet and low-intensity walking in 76 overweight or obese (body mass index > 25 kg/m(2)), Caucasian (72%) or African-American (28%), postmenopausal (age = 60 +/- 5 years) women who completed the study.

RESULTS

Absolute amount of body weight lost was similar in Caucasians (-5.4 +/- 3.6 kg) and African Americans (-3.9 +/- 3.6 kg), but Caucasian women lost relatively more fat mass (p <.05). Both groups decreased their subcutaneous abdominal fat, and Caucasian women decreased their visceral fat area, but there were no racial differences in the magnitude of abdominal fat lost. The intervention decreased triglyceride and increased high-density lipoprotein and high-density lipoprotein 2 cholesterol in both races, and it decreased total and low-density lipoprotein cholesterol in Caucasian women (p <.05-.0001). Fasting glucose and glucose area during the oral glucose tolerance test decreased (p <.0001) in Caucasian women, whereas insulin area decreased in both Caucasian (p <.01) and African-American (p <.05) women. Blood pressure decreased the most in women with higher blood pressures at baseline. Changes in lipids, fasting glucose and insulin, their responses during the oral glucose tolerance test, and blood pressure were not different between racial groups.

CONCLUSIONS

Weight loss achieved through a lifestyle intervention of energy restriction and increased physical activity is an equally effective therapy in African-American and Caucasian obese, postmenopausal women for improving glucose and lipid CHD risk factors.

Lipids, lipoproteins, and exercise

PURPOSE

Dose-response relationships between exercise training volume and blood lipid changes suggest that exercise can favorably alter blood lipids at low training volumes, although the effects may not be observable until certain exercise thresholds are met.

METHODS AND RESULTS

Plasma triglyceride reductions are often observed after exercise training regimens requiring energy expenditures similar to those characterized to increase high-density lipoprotein cholesterol (HDL-C). Thresholds established from cross-sectional and longitudinal exercise training studies indicate that 15 to 20 miles/week of brisk walking or jogging, which elicit between 1,200 to 2,200 kcals of energy expenditure per week, is associated with triglyceride reductions of 5 to 38 mg/dL and HDL-C increases of 2 to 8 mg/dL. Exercise training seldom alters total cholesterol and low-density lipoprotein cholesterol (LDL-C) unless dietary fat intake is reduced and body weight loss is associated with the exercise training program, or both. Thus, for most individuals, the positive effects of regular exercise are exerted on blood lipids at low training volumes and accrue so that noticeable differences frequently occur with energy expenditures of 1,200 to 2,200 kcals/week.

CONCLUSIONS

It appears that weekly exercise caloric expenditures that meet or exceed the higher end of this range are more likely to produce the desired lipid changes. Regarding hyperlipidemic disorders, the primary means for intervention is pharmacologic, whereas diet modification, weight loss, and exercise, although important, are viewed as adjunctive therapies. Because much is known about the exercise training-induced plasma lipid and lipoprotein modifications as well as the mechanisms responsible for these changes, rehabilitation professionals can better develop a comprehensive medical management plan that optimizes pharmacologic, reduced dietary fat intake, weight loss, and exercise interventions.

Exercise and cardioprotection

A wealth of data indicates that performing regular exercise is an important lifestyle modification to prevent cardiovascular disease. Although not fully understood, the cardioprotection by regular exercise may be exerted synergistically through improvement in many risk factors associated with cardiovascular disease. Just as important are the direct effects of exercise on the myocardium, resulting in cardioprotection against ischemia-reperfusion (I-R) injury. Cardioprotective countermeasures against myocardial I-R injury may include the development of collateral coronary arteries, induction of myocardial heat shock proteins, and improved cardiac antioxidant capacity. Improving our understanding of the molecular basis for exercise-induced cardioprotection will play an important role in developing optimal exercise interventions to protect the heart from ischemic injury.

Exercise training and blood lipids in hyperlipidemic and normolipidemic adults: a meta-analysis of randomized, controlled trials

OBJECTIVE

To determine the effectiveness of exercise training (aerobic and resistance) in modifying blood lipids, and to determine the most effective training programme with regard to duration, intensity and frequency for optimizing the blood lipid profile.

DESIGN

Trials were identified by a systematic search of Medline, Embase, Science Citation Index (SCI), published reviews and the references of relevant trials. The inclusion criteria were limited to randomized, controlled trials of aerobic and resistance exercise training which were conducted over a minimum of four weeks and involved measurement of one or more of the following: total cholesterol (TC), high density lipoprotein (HIDL-C), low density lipoprotein (LDL-C) and triglycerides (TG).

SUBJECTS

A total of 31 trials ( 1833 hyperlipidemic and normolipidemic participants) were included.

RESULTS

Aerobic exercise training resulted in small but statistically significant decreases of 0.10 mmol/L (95% CI: 0.02, 0.18). 0.10 (95% CI: 0.02, 0.19), 0.08 mmol/L (95% CI: 0.02, 0.14), for TC, LDL-C, and TG, respectively, with an increase in HDL-C of 0.05 mmol/L (95% CI: 0.02, 0.08). Comparisons between the intensities of the aerobic exercise programmes produced inconsistent results; but more frequent exercise did not appear to result in greater improvements to the lipid profile than exercise three times per week. The evidence for the effect of resistance exercise training was inconclusive.

CONCLUSIONS

Caution is required when drawing firm conclusions from this study given the significant heterogeneity with comparisons. However, the results appear to indicate that aerobic exercise training produced small but favourable modifications to blood lipids in previously sedentary adults.