Exercise as a coronary protective factor

A Randomized Single Dose Parallel Study on Enhancement of Nitric Oxide in Serum and Saliva with the Use of Natural Sports Supplement in Healthy Adults

Sports supplements that stimulate the production of nitric oxide (NO) are widely promoted agents in the sports nutrition domain, and nitric oxide plays an important role to enhance the cardiovascular and physical fitness of the sports participants. The purpose of the study is to investigate whether oral intake of a sports nutritional supplement (Fitnox) is able to increase nitrate (NO₃^-) and nitrite (NO₂^-) levels in blood serum and saliva of healthy adults. Fitnox is a unique blend of Kaempferia parviflora methoxy flavones, pomegranate peel polyphenols, and Moringa oleifera leaf saponins. Twenty-four healthy male adults were equally divided and underwent the double-blind, placebo-controlled clinical trial with a single oral dose of sports nutrition formulation (250 mg capsules); blood and saliva samples were analyzed at different time intervals by high-performance liquid chromatography (HPLC). After administration of Fitnox (250 mg capsule as single dose), NO₃^- and NO₂^- levels in serum and saliva were found to be significantly higher (p <.05) than in the placebo group in 24 hours. Pharmacokinetic parameters such as the area under the plasma concentration-time curve extrapolated to infinity (AUC_0-inf), AUC calculated to the last measured concentration (AUC_0-t), maximum drug serum concentrations (C_max), time of maximum concentration in serum observed (T_max), and time required for the concentration of the drug to reach half of its original value (T_half) were also statistically significant (p <.05) compared with the placebo. The results indicate that a single oral dose of Fitnox is able to increase the NO₃^- and NO₂^- levels considerably in the body relative to placebo for at least 12 hours. Therefore, Fitnox can improve the overall performance of sport participants and enhance physical endurance.

Combined incentives versus no-incentive exercise programs on objectively measured physical activity and health-related variables

Incentivized exercise program interventions have recently led to mixed findings with regard to increasing physical activity, attendance, and improving healthy lifestyles. However, in this area limited research exists on implementing a combined negative reinforcement strategy, using a "buy-in" and positive reinforcement system.

PURPOSE

To determine the effect of comparing a non-incentivized reward system with an incentivized reward system using combined positive and negative rewards on physical activity, attendance, and health and performance outcomes.

METHODS

15 Previously sedentary faculty and staff of a large public research university participated in two separate 12-week exercise interventions and wore a program accelerometer throughout the entire day during the 12weeks. During the first intervention, there were no incentives offered to participants. The second intervention consisted of an incentivized program. Positive reinforcements included various rewards for meeting achievements related to physical activity levels. A program rebate worth $25 for achieving 450miles was used as the negative reinforcement "buy-in" incentive.

RESULTS

A two-way repeated measures ANOVA demonstrated a main effect of time for percent body fat (p<0.001) and push-ups (p=0.018). All other variables revealed no differences between conditions or from pre to post testing. There was no difference between conditions with physical activity or attendance.

CONCLUSION

No differences in physical activity or health-related variables were found within the incentivized and non-incentivized conditions.

Aerobic exercise is promoted when individual performance affects the group: a test of the Kohler motivation gain effect

BACKGROUND

A key barrier to achieving recommended intensity and duration of physical activity is motivation.

PURPOSE

We investigated whether a virtually present partner would influence participants' motivation (duration) during aerobic exercise.

METHOD

Fifty-eight females (M(age) = 20.54 ± 1.86) were randomly assigned to either a coactive condition (exercising alongside another person, independently), a conjunctive condition (performance determined by whichever partner stops exercising first) where they exercised with a superior partner, or to an individual condition. Participants exercised on a stationary bike at 65 % of heart rate reserve on six separate days.

RESULTS

Across sessions, conjunctive condition participants exercised significantly longer (M = 21.89 min, SD = ±10.08 min) than those in coactive (M = 19.77 min, SD = ± 9.00 min) and individual (M = 10.6 min, SD = ±5.84 min) conditions (p < 0.05).

CONCLUSION

Exercising with a virtually present partner can improve performance on an aerobic exercise task across multiple sessions.

Assessment of Cardiovascular Risk Factors Among University Students: The Gender Factor

Background

Evidence indicates that the pathophysiological process of cardiovascular (CV) disease begins at early age, though the manifestations of the disease do not appear until middle age adulthood. Risk factors for CV disease, particularly lipoprotein profiles, are affected by physiological abnormalities, and lifestyle related issues. To evaluate prevalence of CV diseases risk factors among university students and to investigate relation between number of risk factors and body anthropometric, hematological and biochemical indices parameters.

Methods

In this cross sectional study, 348 students were randomly recruited. Blood glucose, cholesterol profile (total, HDL, and LDL cholesterol), and triglyceride were measured using standard protocols. Physical activity (PA) level was assessed using the short-form Arabic version of the International Physical Activity Questionnaires (IPAQ).

Results

The most commonly encountered CV disease risk factor was low levels of HDL-C, followed by physical inactivity, high levels TG, and obese BMI. When stratified by gender, females were less likely to have low HDL-C, and high TG, whereas, males were more likely to have overweight or obese BMI (P < 0.001). About 49% of the participants had at least one CV disease risk factor, where as the prevalence of having one, two and three or more CV disease risk factors were 35.7%, 9.3% and 4%, respectively. Additionally, the number of CV disease risk factors showed strong positive correlation with increases in body fat and bone percentages, glucose, total cholesterol, TG, LDL-C, BMI, and WHR (range of R²: 0.17 to 0.603). On the other hand, physical activity, percentages of body water and muscle, HDL-C showed inverse strong correlation with cardiovascular risk factors (range of R²: -0.239 to -0.412).

Conclusions

Results indicate the high prevalence of CV disease risk factors among university students, and stress the need for early intervention programs to counteract these risks.

Longevity of soccer players: an investigation of all German internationals from 1908 to 2006

Leisure-time physical activity is associated with better health and a reduced risk of all-cause mortality. It is unclear if this association is also present with a high level of physical activity as it is found in professional athletes. In a population-based retrospective cohort study, we compared the survival experience of all soccer players participating for Germany in international matches between 1908 and 2006 to that of the general population. To summarize survival experience, we calculated cumulative relative survival ratios (RSRs) from a life table. We included data of 812 international players, of which 428 (=52.7%) died during follow-up. In all 13 intervals, cumulative observed survival was smaller than cumulative expected survival, resulting in cumulative RSRs being <1. The cumulative RSRs are statistically significantly different from 1 in all but the last interval. This impaired survival experience of the internationals translates into a loss of median residual lifetime of 1.9 years [95% confidence interval: 0.6, 3.2] years at the entry time into the cohort. This loss is mainly driven by the mortality of internationals from the earlier half of the observation period. Reasons for this might be poorer medical care in former times, internationals being killed in action during World War II, and a changing distribution of causes of death during the 20th century.

Mechanisms of anthracycline cardiac injury: can we identify strategies for cardioprotection?

Anthracycline antibiotics have saved the lives of many cancer victims in the 50 plus years since their discovery. A major limitation of their use is the dose-limiting cardiotoxicity. Efforts focusing on understanding the biochemical basis for anthracycline cardiac effects have provided several strategies currently in clinical use: limit dose exposure, encapsulate anthracyclines in liposomes to reduce myocardial uptake, administer concurrently with the iron chelator dexrazoxane to reduce free iron-catalyzed reactive oxygen species formation; and modify anthracycline structure in an effort to reduce myocardial toxicity. Despite these efforts, anthracycline-induced heart failure continues to occur with consequences for both morbidity and mortality. Our inability to predict and prevent anthracycline cardiotoxicity is, in part, due to the fact that the molecular and cellular mechanisms remain controversial and incompletely understood. Studies examining the effects of anthracyclines in cardiac myocytes in vitro and small animals in vivo have demonstrated several forms of cardiac injury, and it remains unclear how these translate to the clinical setting. Given the clinical evidence that myocyte death occurs after anthracycline exposure in the form of elevations in serum troponin, myocyte cell death seems to be a probable mechanism for anthracycline-induced cardiac injury. Other mechanisms of myocyte injury include the development of cellular "sarcopenia" characterized by disruption of normal sarcomere structure. Anthracyclines suppress expression of several cardiac transcription factors, and this may play a role in the development of myocyte death as well as sarcopenia. Degradation of the giant myofilament protein titin may represent an important proximal step that leads to accelerated myofilament degradation. An interesting interaction has been noted clinically between anthracyclines and newer cancer therapies that target the erbB2 receptor tyrosine kinase. There is now evidence that erbB2 signaling in response to the ligand neuregulin regulates anthracycline uptake into cells via the multidrug-resistance protein. Therefore, up-regulation of cardiac neuregulin signaling may be one strategy to limit myocardial anthracycline injury. Moreover, assessing an individual's risk for anthracycline injury may be improved by having some measure of endogenous activity of this and other myocardial protective signals.

A randomized controlled trial evaluating the impact of knowledge translation and exchange strategies

Context

Significant resources and time are invested in the production of research knowledge. The primary objective of this randomized controlled trial was to evaluate the effectiveness of three knowledge translation and exchange strategies in the incorporation of research evidence into public health policies and programs.

Methods

This trial was conducted with a national sample of public health departments in Canada from 2004 to 2006. The three interventions, implemented over one year in 2005, included access to an online registry of research evidence; tailored messaging; and a knowledge broker. The primary outcome assessed the extent to which research evidence was used in a recent program decision, and the secondary outcome measured the change in the sum of evidence-informed healthy body weight promotion policies or programs being delivered at health departments. Mixed-effects models were used to test the hypotheses.

Findings

One hundred and eight of 141 (77%) health departments participated in this study. No significant effect of the intervention was observed for primary outcome (p < 0.45). However, for public health policies and programs (HPPs), a significant effect of the intervention was observed only for tailored, targeted messages (p < 0.01). The treatment effect was moderated by organizational research culture (e.g., value placed on research evidence in decision making).

Conclusion

The results of this study suggest that under certain conditions tailored, targeted messages are more effective than knowledge brokering and access to an online registry of research evidence. Greater emphasis on the identification of organizational factors is needed in order to implement strategies that best meet the needs of individual organizations.

Trial Registration

The trial registration number and title are as follows: ISRCTN35240937 -- Is a knowledge broker more effective than other strategies in promoting evidence-based physical activity and healthy body weight programming?

Psychosocial work conditions, unemployment, and leisure-time physical activity: a population-based study

OBJECTIVE

To investigate the association between psychosocial work conditions and unemployment, and low leisure-time physical activity.

DESIGN/SETTING/PARTICIPANTS/MEASUREMENTS

The 2000 public health survey in Scania is a cross-sectional postal questionnaire study with a 59% participation rate. A total of 5,180 persons aged 18-64 years who belonged to the workforce and the unemployed were included in this study. Logistic regression models were used to investigate the associations between psychosocial factors at work and unemployment, and low leisure-time physical activity. Psychosocial conditions at work were defined according to the Karasek-Theorell demand-control/decision latitudes into relaxed, active, passive, and job strain categories. The multivariate analyses included age, country of birth, education, economic stress, and social participation.

RESULTS

In total, 16.1% of men and 14.8% of women had low leisure-time physical activity. The job strain (high demands/low control) and unemployed categories had significantly higher odds ratios of low leisure-time physical activity among both men and women compared with the relaxed (low demands/high control) reference category. However, the significant differences between the job strain, the unemployed, and the relaxed categories disappeared in the multivariate models.

CONCLUSIONS

Respondents with job strain or unemployment have significantly higher odds ratios of low leisure-time physical activity than the relaxed category. However, after adjustments for education in particular the differences disappear. Nevertheless, the results suggest that the association between psychosocial work conditions, which are often dependent on education, and leisure-time physical activity may be interesting to study in more detail.

Exercise considerations in coronary artery disease, peripheral vascular disease, and diabetes mellitus

Physical inactivity is a risk factor for cardiovascular disease. Regular aerobic and resistance training increases exercise capacity and plays a role both in the primary and secondary prevention of cardiovascular disease. Patients with coronary artery disease, peripheral vascular disease, or diabetes mellitus must be considered individually when prescribing exercise because their clinical status can vary greatly. In addition, a majority of these patients have multiple comorbid disorders such as renal, neurologic, and retinal disease that may affect their ability to exercise safely. Therefore, a preparticipation medical evaluation is required. An exercise prescription should be tailored to each person's unique set of circumstances and reflect an effort to maximize the anticipated benefits while minimizing the risks.

Myocardial ischemia during physical exercise in patients with stable coronary artery disease: predictability and prevention

AIMS

We assessed whether exercise-induced myocardial ischemia during intensive group exercise sessions can be predicted in patients with coronary artery disease and stable angina pectoris.

METHODS AND RESULTS

Twenty-three patients underwent cardiac catheterization, 201-thallium scintigraphy, and exercise testing prior to participation in group training sessions. Heart rates and myocardial ischemia were documented by Holter monitoring. The individual training heart rate was calculated as a percentage of the maximal heart rate achieved during symptom-limited exercise testing. Myocardial ischemia occurred significantly more often during group exercise sessions (15 of 23 patients) than during treadmill testing (4 of 23 patients, P<0.001). Maximal heart rate (145+/-23 vs. 134+/-21 beats/min, P<0.004) and maximal plasma lactate concentrations (6.0+/-2.9 vs. 4.3+/-2.0 mmol/l, P<0.05) were significantly higher than during symptom-limited exercise testing. Ischemic episodes occurred significantly more often during jogging than during competitive ball games or interval training. Myocardial ischemia occurred in patients who exceeded their individual target training heart rates (43 of 44 episodes; P<0.001). Duration of ischemic episodes did not correlate with any marker obtained at the beginning of the study.

CONCLUSION

These data demonstrate that routine diagnostic procedures do not sufficiently identify patients at risk for exercise-induced myocardial ischemia. Ischemic events are only effectively prevented by choosing adequate types of exercise and, above all, by the strict adherence to individual target heart rates.

Preparation of a monoclonal antibody to N(epsilon)-(Hexanonyl)lysine: application to the evaluation of protective effects of flavonoid supplementation against exercise-induced oxidative stress in rat skeletal muscle

The monoclonal antibody to N(epsilon)-(hexanonyl)lysine (HEL), a novel adduct formed by the reaction of linoleic acid hydroperoxide and lysine, has been prepared and characterized. The obtained antibody specifically recognized the HEL moiety. Using the monoclonal antibody, we evaluated the protective effects of feeding eriocitrin, which is one of flavonoids in lemon fruit, on oxidative modification induced by exercise in rats. The supplementation of eriocitrin significantly suppressed the increase in HEL in the skeletal muscle by exercise. The result suggests that the determination of HEL may be a good method for evaluation of the protective effect of beneficial food factors against oxidative stress.

Aging, physical conditioning, and exercise-induced changes in hemostatic factors and reaction products

The influence of age on training-induced changes in resting and stimulated hemostatic potential was studied in three age categories (Cat I-III; 20-30 yr, 35-45 yr, and 50-60 yr, respectively) of sedentary men before and after 12 wk of training. Coagulation, fibrinolytic activity, and activation markers (reflecting fibrin formation and degradation) were determined. Physical conditioning resulted in a more pronounced increase in von Willebrand factor (vWF) and factor VIII clotting activity (FVIII:c) in Cat I and II and a more pronounced shortening of the activated partial thromboplastin time in all categories at maximal exertion and during recovery. Enhanced increases in tissue-type plasminogen activator (t-PA) antigen and activity and single-chain (sc) urokinase-type plasminogen activator (u-PA) at maximal exercise and 5 min of recovery were observed in all age groups after training. The effects on FVIII:c, vWF, and scu-PA were most pronounced in the youngest age group (Cat I). Increases in the marker of thrombin generation were highest in Cat III; no effect was seen on thrombin-antithrombin complex, plasmin-antiplasmin complex, and D-dimer in any of the age groups. We concluded that training enhances both coagulation and fibrinolytic potential during strenuous exercise. The effect on FVIII/vWF and t-PA/u-PA is most pronounced in younger individuals, whereas thrombin formation is most pronounced in older individuals.

Cardiac assessment of veteran endurance athletes: a 12 year follow up study

OBJECTIVES

Sustained aerobic dynamic exercise is beneficial in preventing cardiovascular disease. The effect of lifelong endurance exercise on cardiac structure and function is less well documented, however. A 12 year follow up of 20 veteran athletes was performed, as longitudinal studies in such cohorts are rare.

METHODS

Routine echocardiography was repeated as was resting, exercise, and 24 hour electrocardiography.

RESULTS

Nineteen returned for screening. Mean (SD) age was 67 (6.2) years (range 56-83). Two individuals had had permanent pacemakers implanted (one for symptomatic atrial fibrillation with complete heart block, the other for asystole lasting up to 15 seconds). Only two athletes had asystolic pauses in excess of two seconds compared with seven athletes in 1985. Of these seven, five had no asystole on follow up. Two of these five had reduced their average running distance by about 15-20 miles a week. One athlete sustained an acute myocardial infarction during a competitive race in 1988. Three athletes had undergone coronary arteriography during the 12 years of follow up but none had obstructive coronary artery disease. Ten of 19 (53%) had echo evidence of left ventricular hypertrophy in 1997 but only two (11%) had left ventricular dilatation. Ten athletes had ventricular couplets on follow up compared with only two in 1985.

CONCLUSIONS

Although the benefits of moderate regular exercise are undisputed, high intensity lifelong endurance exercise may be associated with altered cardiac structure and function. These adaptations to more extreme forms of exercise merit caution in the interpretation of standard cardiac investigations in the older athletic population. On rare occasions, these changes may be deleterious.

A marathon run increases the susceptibility of LDL to oxidation in vitro and modifies plasma antioxidants

Physical activity increases the production of oxygen free radicals, which may consume antioxidants and oxidize low-density lipoprotein (LDL). To determine whether this occurs during strenuous aerobic exercise, we studied 11 well-trained runners who participated in the Helsinki City Marathon. Blood samples were collected before, immediately after, and 4 days after the race to determine its effect on circulating antioxidants and LDL oxidizability in vitro. LDL oxidizability was increased as determined from a reduction in the lag time for formation of conjugated dienes both immediately after (180 +/- 7 vs. 152 +/- 4 min, P < 0.001) and 4 days after (155 +/- 7 min, P < 0.001) the race. No significant changes in lipid-soluble antioxidants in LDL or in the peak LDL particle size were observed after the race. Total peroxyl radical trapping antioxidant capacity of plasma (TRAP) and uric acid concentrations were increased after the race, but, except for TRAP, these changes disappeared within 4 days. Plasma thiol concentrations were reduced after the race. No significant changes were observed in plasma ascorbic acid, alpha-tocopherol, beta-carotene, and retinol concentrations after the marathon race. We conclude that strenuous aerobic exercise increases the susceptibility of LDL to oxidation in vitro for up to 4 days. Although the increase in the concentration of plasma TRAP reflects an increase of plasma antioxidant capacity, it seems insufficient to prevent the increased susceptibility of LDL to oxidation in vitro, which was still observed 4 days after the race.

Influence of intensive physical training on urinary nitrate elimination and plasma endothelin-1 levels in patients with congestive heart failure

BACKGROUND

Congestive heart failure (CHF) is associated with increased peripheral vascular resistance. Exercise-induced shear stress may release endothelial relaxing factors, such as nitric oxide (NO), and inhibit the production of vasoconstrictors such as endothelin-1 (ET-1) thereby modulating vascular tone. We examined the effect of intensive training on ET-1 plasma concentrations and NO-metabolite elimination in patients with CHF after acute myocardial infarction.

METHODS

Seventeen patients with CHF after a myocardial infarction were randomized to an exercise group (n = 9), who performed physical training for 8 weeks, or a control group (n = 8) who received usual care. A physical examination, pulmonary function test, and a maximum exercise test were performed, and 24-hour urinary nitrate elimination and ET-1 in plasma were determined before and at the end of the study period.

RESULTS

Maximal oxygen uptake remained unchanged in controls (17.9 +/- 1.4 to 18.1 +/- 1.5 mL/(kg min) but increased in the exercise group (from 20.4 +/- 0.75 to 26.7 +/- 1.4 mL/(kg min). After 8 weeks the urinary nitrate elimination in controls was significantly decreased (1.25 +/- 0.20 to 1.03 +/- 0.22 mmol/24 hours; P < 0.001), while it was unchanged in the exercise group (1.26 +/- 0.23 to 1.39 +/- 0.28; P = 0.71). Plasma ET-1 levels did not change after 8 weeks (7.87 +/- 0.62 versus 7.57 +/- 0.75 and 7.13 +/- 0.6 versus 7.35 +/- 0.7 pg/mL for control and exercise groups, respectively).

CONCLUSION

In patients with CHF after acute myocardial infarction nitrate elimination decreases over the subsequent 2 months. This trend was reversed by training. Because nitrate elimination mirrors endogenous NO production, these results suggest that training may positively influence endothelial vasodilator function.

Increase in nitric oxide formation after chronic voluntary exercise in spontaneously hypertensive rats

The effect of chronic voluntary exercise on the plasma level of nitrate, a major stable metabolite of nitric oxide (NO) was studied in spontaneously hypertensive rats (SHR). Exercise consisted of spontaneous running in wheels for 3-35 days. Blood samples were collected after 3, 7, 14, 21 and 35 days of exercise and all samples were drawn after the running wheel had been locked during the preceding 12 h. The plasma nitrate level was significantly (P < 0.05) elevated in SHR after 35 days of exercise. Surprisingly after 7 days of exercise a significant (P < 0.001) decrease in the nitrate level in plasma was noted. Further research is needed to elucidate this biphasic change in nitrate seen in this study. The elevated level of plasma nitrate seen after 35 days of voluntary exercise was still present up to 36 h after termination of exercise. We conclude that exercise training in SHR elicits an enhanced formation of NO.

[Effect of physical activity on incidence of sudden cardiac death. Study of the Berlin-Reinickendorf and Berlin-Spandau population]

AIM

Our investigation examined the influence of regular physical activity and sudden extrenious situations on the incidence of sudden cardiac death (scd) in two different Berlin districts with a total population of 219,251 in the examined age-groups.

PATIENTS AND METHOD

All cases of scd which occurred outside of the hospital and were documented as been induced from ventricular fibrillation were examined over a time period of 18 months. For each case the amount of and the intensity of their regular physical activity was determined. In addition the stress of the sudden extrenious situations was survived. The study population was divided into various groups depending upon their level of regular physical activity. For each group the incidence of sudden cardiac death was determined. Then the relative risk for scd during strenuous activity compared to inactivity was determined for each group. The influence of preexisting disease was calculated.

RESULTS

77 patients with scd induced from ventricular fibrillation were included in our study. In the sedentary group we found an incidence of 4.69 scd per 10(5) person-years, in the group with a low level of regular physical activity we found an incidence of 4.25, in the group with a middle level of regular physical activity an incidence of 2.63 and in the most active group 0.92 scd per 10(5) person-years. We found the relative risk for scd during highly strenuous activity compared with inactivity to be 150 in the sedentary group as opposed to 4.0 in the most active group. The preexisting illness status of the case-groups had no influence on the outcome.

CONCLUSIONS

The results show that the risk of scd for all persons regardless of their levels of regular physical activity and their preillness status is higher during strenuous activity than during inactivity. The increase of the risk for scd during activity is the highest for persons with sedentary lifestyles, whereas the risk increase for persons with active lifestyles is minimal. The protective effect of regular physical activity for scd by far exceeds the risk increase of the actual strenuous situation.

Exercise metabolism in healthy volunteers taking celiprolol, atenolol, and placebo

OBJECTIVE

Previous studies have shown that beta 1 selective agents have fewer adverse effects on exercise metabolism than nonselective beta blockers, and this has been attributed to their reduced blockade of beta 2 receptors. This study aimed at determining whether a beta blocker with partial agonist activity at beta 1 and beta 2 receptors (celiprolol) was better than a conventional beta 1 receptor-blocker (atenolol) in prolonging exercise capabilities.

METHODS

After four days of treatment with celiprolol 200 mg, atenolol 50 mg, or placebo, 22 healthy volunteers exercised on a treadmill for two hours at 50% of their maximal oxygen uptake. Resting heart rate and blood pressure were recorded before and after exercise. During exercise, fat oxidation, plasma free fatty acids, glycerol, glucose, and ammonia were measured together with heart rate and perceived exertion.

RESULTS

Mean exercising heart rate was significantly lower in those taking either of the beta blockers than in those taking placebo, and significantly lower for those taking atenolol rather than celiprolol. Fat oxidation was significantly lower for those taking celiprolol (38.8 (SD 12.2)%, P < 0.01) and atenolol (36.6 (15.9)%, P < 0.01) compared with placebo (45.6 (14.1)%). For the first 15 minutes of exercise, fat oxidation was significantly lower for those taking atenolol (24.6 (12.8)%, P < 0.01) than celiprolol (29.6 (14.3)%). The rise in plasma free fatty acids and glycerol during exercise was also significantly attenuated by both beta blockers in comparison with the rise in those taking placebo (P < 0.01).

CONCLUSIONS

Both celiprolol and atenolol reduced fat oxidation compared with placebo. For the first 15 minutes of exercise fat oxidation was preserved by celiprolol, but not atenolol. This preservation of fat oxidation during the early part of exercise may confer some small benefit to patients who take beta blockers and intend to exercise regularly. However, we did not detect significant differences between atenolol and celiprolol in overall mean fat oxidation or perceived exertion in this study.

Both physical fitness and acute exercise regulate nitric oxide formation in healthy humans

We analyzed nitrate, a major stable end product of nitric oxide (NO) metabolism in vivo in plasma and urine from groups of healthy subjects with different working capacities. Resting plasma nitrate was higher in athletic subjects than in nonathletic controls [45 +/- 2 vs. 34 +/- 2 (SE) microM; P < 0.01]. In other subjects, both the resting plasma nitrate level (r = 0.53; P < 0.01) and the urinary excretion of nitrate at rest (r = 0.46; P < 0.01) correlated to the subjects' peak work rates, as determined by bicycle ergometry. Two hours of physical exercise elevated plasma nitrate by 18 +/- 4 (P < 0.01) and 16 +/- 6% (P < 0.01), respectively, in athletes and nonathletes, compared with resting nitrate before exercise. We conclude that physical fitness and formation of NO at rest are positively linked to each other. Furthermore, a single session of exercise elicits an acute elevation of NO formation. The observed positive relation between physical exercise and NO formation may help to explain the beneficial effects of physical exercise on cardiovascular health.

Effect of endurance training and seasonal fluctuation on coagulation and fibrinolysis in young sedentary men

The effect of 12 wk of submaximal training on hemostatic variables was studied in 20 young sedentary men (Tr) and 19 nontraining matched controls (Con). After training, a more pronounced increase in factor VIII coagulant activity (P < 0.01), reflected in a decrease in activated partial thromboplastin time (P < 0.01) during maximal exercise, was seen. Both basal plasminogen activator inhibitor 1 antigen (PAI-1 Ag) and activity (PAI-1 Act; P < 0.05), as well as basal and exercise-induced tissue-type plasminogen activator antigen (t-PA Ag; P < 0.05), were decreased after training. The overall effect on fibrinolysis was reflected in an increase in the t-PA Act/t-PA Ag ratio in the Tr group. In contrast, during the same period (February-June), the Con group demonstrated an increase in basal PAI-1 Ag and PAI-1 Act (P < 0.05), together with an increase in basal and exercise-induced t-PA Ag (P < 0.05). Both basal and exercise-induced t-PA Act were unchanged, but t-PA Act/t-PA Ag was decreased (P < 0.05) in the Con group. We conclude that physical training promotes both coagulation and fibrinolytic potential during exercise and may reverse unfavorable seasonal effects on fibrinolysis.

Modification of physical activity 5 months after myocardial infarction: relevance of biographic and personality characteristics

The relation between modification of physical activity, a risk factor for coronary heart disease, and personality characteristics was assessed in 166 survivors of a first myocardial infarction (MI). Physical activity was assessed before MI in retrospect and again 5 months after MI. Patients were divided into 3 categories according to their current daily-life physical activities: less active than before MI (n=24), equally active as before MI (n=82), or more active than before MI (n=60). A significant differentiation was found between patients who became less physically active than before MI and the other 2 categories. This less active category was characterized by feelings of disability, a low level of vigor, and feelings of anxiety. In addition, this patient group was on average older and more often female. The results were adjusted for participation in a cardiac rehabilitation program. Finally, the discussion recommends involving psychological intervention in the exercise program for the less active category of patients to diminish feelings of anxiety and disability and to improve vigor.

Oxygen uptake and its relation to physical activity and other coronary risk factors in asymptomatic middle-aged Japanese

PURPOSE

Low physical activity is considered to be an important risk factor for atherosclerotic coronary artery disease. However, few data are reported on the Japanese general population. The authors have studied whether oxygen uptake in physical fitness evaluation is a quantitative index for physical activity and whether or not it has a relation to coronary risk factors.

METHODS

Five hundred thirteen asymptomatic Japanese (40-64 years of age, 282 males and 231 females) were tested on a cycle ergometer for measurement of peak oxygen uptake (peak VO2) and oxygen uptake at anaerobic threshold (VO2AT). Physical activity was estimated by pedometer score. Data for oxygen uptake were adjusted by age or by age and body mass index (BMI), then its relationship to the following risk factors was investigated: physical activity, BMI, blood pressure, total cholesterol, HDL and LDL cholesterol, fasting blood glucose, and triglycerides.

RESULTS

Subjects in the highest peak VO2 quartile walked significantly more than those in the lowest quartile in both males and females. Those in the highest quartile showed lower BMI, lower blood pressure, lower triglyceride, and higher HDL cholesterol. The same relationship was observed for VO2AT.

CONCLUSIONS

Higher fitness level determined by peak VO2 or VO2AT is related to higher physical activity and lower coronary risk factors in the asymptomatic middle-aged Japanese. These data provide support for exercise prescription in the primary prevention of coronary heart disease in Japan.

Acute effects of beta blockade and exercise on mood and anxiety

OBJECTIVE

To measure the previously reported beta blocker induced adverse changes in mood state and anxiety measures, and to determine if prolonged aerobic exercise attenuates such mood modifications.

METHODS

After 4 days of drug treatment with comparable doses of propranolol (40 and 80 mg), metoprolol (50 and 100 mg), or placebo, mood (POMS) and anxiety states (STAI) were assessed in healthy volunteers, before and after 1 h of treadmill walking exercise at 50% maximum oxygen uptake.

RESULTS

Compared to placebo, resting "tension", "depression", and "total mood disturbance" were significantly higher on propranolol 80 mg, but all were reduced with exercise. "Fatigue" and "confusion" were also higher on propranolol, and were unaffected by exercise. "Fatigue" was also higher than placebo after exercise on metoprolol 100 mg. "Anxiety" was unaffected by drug treatment or exercise.

CONCLUSIONS

The evidence that beta blockers, and particularly propranolol, have adverse effects on mood was confirmed. It would be preferable to prescribe a beta blocker which does not adversely alter mood states. However, exercise significantly reduced the measures of "tension" and "depression" which were adversely increased by propranolol. Exercise prescription may therefore not only be compatible with beta blockade, but a highly desirable adjuvant therapy.

Adherence in the training levels comparison trial

In the Training Levels Comparison Trial, 197 male coronary heart disease patients were randomized to low or high intensity training with target heart rates, which corresponded to 50% and 85% of the VO2max achieved on the previous exercise test, respectively. Patients were to exercise at their assigned intensity level at three 1-h long supervised sessions per week for 2 yr. This paper reports on two components of adherence: attendance at exercise sessions and achievement of heart rates in the target range. During the first year of training, the average percent of exercise sessions attended (mean +/- SE) for the low intensity group (64.0 +/- 2.5%) was significantly higher than for the high intensity group (55.5% +/- 2.7%). At the end of 1 yr of training, 54% and 37% of the low and high intensity patients, respectively, achieved heart rates within 5 beats.min-1 of their target heart rates. Although the low intensity program was preferable to achieve maximum attendance, attenders on the high intensity program achieved higher heart rates. These results suggest that to maximize the achieved heart rate, it would be optimal to motivate a cardiac rehabilitation patient to train at the high intensity level for a prolonged period of time.

Physical fitness and perceived stress. Relationships with coronary artery disease risk factors

This study evaluated the relationship between two biochemical risk factors for coronary artery disease, serum lipids and dehydroepiandrosterone-sulfate (DHEA-S), and both fitness and perceived stress among a cohort of senior male Army officers (N = 331). The participants underwent a number of assessments gauging their fitness [exercise tolerance as measured by maximum ventilatory oxygen uptake (MVO2)], psychological well-being, and biochemical cardiovascular risk factors. Perceived stress was significantly and inversely related to DHEA-S levels, even after adjusting for age, though no relationship was found between perceived stress and serum lipids. Significant correlations were found between MVO2 and high-density lipoprotein cholesterol and inversely between MVO2 and triglycerides. Overall, the study's findings are generally consistent with the view that psychological stress and physical activity have opposite effects on parameters that affect cardiovascular status.

Exercise metabolism during 1 hour of treadmill walking while taking high and low doses of propranolol, metoprolol, or placebo

Aerobic exercise and beta-blocking drugs are regularly prescribed as treatment for hypertension and as a prophylactic for patients at risk from coronary heart disease and for those recovering from an infarct. Some beta blockers, particularly non-beta 1-selective drugs, may make exercise more difficult, possibly by interfering with substrate metabolism during exercise. This study examined the effects of low and high doses of a beta 1-selective blocker, metoprolol, and a non-selective beta blocker, propranolol, on exercise metabolism. The study involved 20 healthy subjects (10 men, 10 women) who walked on a treadmill at 50% of their maximal oxygen uptake for 1 h on five occasions, separated by 7 days. On each of the five occasions they received one of the following treatments, given in random order: placebo, metoprolol 50 mg, metoprolol 100 mg, propranolol 40 mg, or propranolol 80 mg, all taken twice daily. Fat oxidation, expressed as a percentage of total energy expenditure, was significantly lower than with placebo for all of the active treatments except metoprolol 50 mg (placebo: 42.7 +/- 11.6%; metoprolol 50 mg: 38.7 +/- 14.1%, p = NS; metoprolol 100 mg: 36.3 +/- 13.7%, p = 0.05; propranolol 40 mg: 31.2 +/- 9.3%, p = 0.01; propranolol 80 mg: 29.5 +/- 10.9%, p = 0.01); and significantly lower with propranolol than with metoprolol (propranolol 40 mg: p = 0.0036; propranolol 80 mg: p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of patients at risk during swimming by Holter monitoring

Cardiac arrest during swimming accounts for a considerable number of deaths during physical exercise in patients with coronary artery disease. A link between ST-segment depression and cardiac arrest has been observed in previous studies. In this study, exercise-induced myocardial ischemia was assessed in 23 patients with coronary artery disease by bipolar Holter monitoring during swimming, jogging, and treadmill testing. During treadmill testing, Holter monitoring and standard electrocardiograms were simultaneously recorded. Detection of ST-segment depression during swimming was standardized in a group of normal volunteers (n = 7). All patients with silent myocardial ischemia (n = 8) documented by thallium-201 scintigraphy had ST-segment depression during treadmill testing and swimming when recorded by Holter monitoring, whereas the standard electrocardiogram during treadmill testing was negative in 5 patients. Heart rate at 1 mm ST-segment depression was significantly lower during swimming (110 +/- 11 beats/min) than during treadmill testing (documented by standard electrocardiogram) (133 +/- 23 beats/min, p < 0.002) and jogging (125 +/- 21 beats/min, p < 0.03). However, there was no significant difference in heart rate at onset of angina pectoris in symptomatic patients, suggesting a delayed sensation of ischemic symptoms during swimming. The only clinical event in our group during 8 years of swimming occurred during this study. One patient with silent myocardial ischemia developed ST-segment depression during swimming that degenerated into ventricular fibrillation, requiring resuscitation. Therefore, Holter monitoring can be considered a valuable addition in identifying patients with silent myocardial ischemia during swimming, and thus identifying patients at risk for exertion-related life-threatening ventricular tachyarrhythmias.

Physical conditioning decreases norepinephrine-induced vasoconstriction in rabbits. Possible roles of norepinephrine-evoked endothelium-derived relaxing factor

BACKGROUND

Physical activity can reduce sympathetic tone and may be beneficial to human health. Whether the vascular responses to norepinephrine (NE), an adrenergic vasoconstrictor, could be altered by chronic exercise was unclear. We therefore conducted this study to investigate the effects of endurance exercise training on NE-induced vasoconstrictive response in healthy rabbits. Possible mechanisms were also studied.

METHODS AND RESULTS

Twenty-four male New Zealand White rabbits were used for this study. They were divided into two groups: control and training. The training group was trained on a treadmill with running speed of 0.88 km/h at a 0 degree grade for 10 to 60 minutes per day, for 5 days a week for a total of 8 weeks. At the end of the experiments, thoracic aortae (3 mm long) were isolated. The vascular tension was measured with a force transducer. The dose-response relation of NE-induced vasoconstriction was determined and compared for control (n = 5) and trained (n = 6) groups. To verify the possible involvement of endothelium-derived relaxing factor (EDRF) in the alteration of NE-induced vasoconstriction after exercise training, we compared the vascular responses to NE in endothelium-intact, N omega-nitro-L-arginine (L-NNA, 10(-4) mol/L)-pretreated, or denuded vessel segments (n = 4 for each experiment of each group). EDRF release in the presence or absence of NE was also evaluated by the increased tension induced by hemoglobin (10(-5) mol/L), an EDRF scavenger (n = 6 for the control group and n = 8 for the trained group). In addition, vascular responses to some specific adrenergic agonists (ie, phenylephrine, an alpha 1-agonist, and clonidine, an alpha 2-agonist) were also studied to see if a specific adrenergic receptor was involved (n = 4 for each experiment of each group). Our results indicated that (1) [NE]ED50 of the thoracic aorta was elevated by exercise training; (2) in the presence of NE, EDRF release from the thoracic aorta, assessed by addition of hemoglobin or L-NNA, was higher in the trained group than in the control group; (3) both phenylephrine (10(-8) mol/L) and clonidine (10(-6) mol/L) could evoke vasorelaxation that would be inhibited by L-NNA; and (4) in addition to causing vasoconstriction, NE could stimulate EDRF release, possibly via alpha 1- and alpha 2-receptors of endothelial cells.

CONCLUSIONS

Our data suggest that exercise training may decrease NE-induced vasoconstrictive response and may increase NE-stimulated EDRF release.

Dyslipidemias and the secondary prevention of coronary heart disease

Dyslipidemias in patients with coronary heart disease confer a greater risk of ischemic cardiac events than comparable dyslipidemias in people free of disease. A major dyslipidemia can be diagnosed in more than 80% of patients with established premature coronary heart disease. These dyslipidemias constitute not only elevations of low-density lipoprotein cholesterol (hypercholesterolemia) but also indicate abnormalities in the metabolism of triglyceride-rich lipoproteins, high-density lipoproteins, and lipoprotein(a). Clinical trials have demonstrated that therapy to lower low-density lipoprotein levels can delay angiographic progression of coronary stenoses and reduce recurrent cardiac event rates. These clinical benefits from low-density lipoprotein cholesterol lowering may occur as early as 6 to 12 months after initiation of therapy. Intervention strategies for dyslipidemias are directed toward lowering the low-density lipoprotein cholesterol fraction to 90 to 100 mg/dl. This approach begins with dietary modification, weight loss, smoking cessation, and aerobic exercise. Patients with hypercholesterolemia refractory to nonpharmacologic intervention require lipid-lowering agents. The choice of lipid-lowering medications is influenced by concomitant abnormalities of lipoprotein metabolism, such as hypertriglyceridemia or hypoalphalipoproteinemia. Treatment of primary dyslipidemias other than hypercholesterolemia may be warranted in the presence of other cardiac risk factors; however, a broader spectrum of clinical trial data is needed to support or refute this contention.

Effects of exercise training on the chemical composition of plasma LDL

The purpose of the present study was to determine the effects of exercise training on the chemical composition of plasma low-density lipoprotein (LDL). Thirteen men (mean age +/- SE, 47.2 +/- 1.5 years) were examined before and after 14 weeks of endurance-oriented exercise training (3 to 4 d/wk, 30 to 45 min/d). Although calculated plasma LDL concentrations remained unaltered (3.49 +/- 0.24 versus 3.65 +/- 0.23 mmol/L), changes in the chemical composition of LDL (increased LDL free cholesterol, cholesterol ester, and phospholipid content) were associated with a reduction in adiposity, umbilical girth, and basal plasma insulin and glucose concentration with training intervention. Increases in LDL molecular weight and particle diameter were associated with a reduction in fat mass, plasma triglyceride concentration, and basal plasma glucose concentration with physical activity. The LDL lipid-to-protein ratio also increased (P < .01) with training by 7%, primarily due to an increase in LDL free cholesterol content (P < .01). These findings indicate the formation of LDL particles that are more cholesterol enriched and protein poor with exercise training, which provides additional evidence for the cardioprotective effect of long-term physical activity.

Relative risk of factors for coronary heart disease in population with low cholesterol levels

We studied the odds ratios of seven leading risk variables in a population essentially having a 'low' cholesterol concentration. In a cross-sectional population-based study of 3689 Turkish adults 20 years of age or over, 90 men and 83 women were diagnosed to have definite or suspected coronary heart disease. The criteria were based on history, cardiovascular examination and on Minnesota coding of electrocardiograms. Potential risk factors studied were: plasma total cholesterol (> or = 240 mg/dl), fasting triglycerides (> or = 200 mg/dl), diabetes mellitus, hypertension (asystolic > or = 160 mmHg, diastolic > or = 95 mmHg, or both, or subjects reporting to take antihypertensive medication), smoking currently or in the past, obesity (body mass index > or = 30 kg/m2), and physical inactivity. Hypertension and lack of physical exercise constituted the most important risk factors in both sexes being valid for all age groups and having high attributable risks; odds ratios in men and women, respectively, were 3.16 and 2.6 for hypertension, and 2.16 and 3.49 for physical inactivity. Hypertriglyceridemia followed these factors in men with an odds ratio of 2.15. In women an additional significant factor was obesity (odds ratio 1.76), while diabetes and hypercholesterolemia revealed to be significant only in those aged 20-59 years, and smoking in women aged 30-59 years. Among men, smoking was a borderline significant risk factor for coronary disease, whereas hypercholesterolemia did not prove to be so. These findings, somewhat at variance with those of industrialized nations, may have significance for policy of cardiovascular disease prevention in third-world populations.

Physical conditioning can modulate endothelium-dependent vasorelaxation in rabbits

To investigate whether exercise training can modulate endothelium-dependent vasorelaxation, male New Zealand White rabbits were divided into either control or training groups. The training animals were trained on a treadmill with a running speed of 0.88 km/hr on a 0 degree grade for 10-60 minutes/day, 5 days/week for 8 weeks. After exercise training, the resting heart rate was lowered (p < 0.05). At the end of the experiments, three vessel segments, i.e., the thoracic aortas, the pulmonary arteries, and the common carotid arteries, were isolated and precontracted with norepinephrine. Acetylcholine-stimulated endothelium-derived relaxing factor (EDRF) release was assessed by bioassay in the presence of indomethacin (10(-5) M). Basal release of EDRF was examined by the addition of hemoglobin. In addition, the relaxing responses of the thoracic aortas and pulmonary arteries to A23187, a calcium ionophore, and to sodium nitroprusside, a direct vasodilator of vascular smooth muscle, were compared between control and trained groups to further investigate possible underlying mechanisms. The results indicated that after exercise training 1) both the thoracic aorta and pulmonary artery, but not the carotid artery, became more sensitive to acetylcholine-induced vasorelaxation; 2) no significant differences in basal release of EDRF between control and trained rabbits were observed; and 3) there were no significant differences in the vascular responses to A23187 or sodium nitroprusside between the two groups. Our data suggest that exercise training may enhance endothelium-dependent vasodilation to acetylcholine via the stimulated EDRF release and that this elevated sensitivity to acetylcholine may not be caused by the alteration of the relaxing response in vascular smooth muscle.

Acute and delayed effects of prolonged exercise on serum lipoproteins. II. Concentration and composition of low-density lipoprotein subfractions and very low-density lipoproteins

To investigate the effects of a single period of prolonged exercise on lipoprotein concentration and composition, 13 healthy endurance-trained men were examined before and after (1 h, 20 h) a cross-country run [30 km, time: 130 (SD 7.4) min]. The data show that following acute exercise, serum triglyceride (TG) concentration were reduced (36%) as a consequence of a reduced number (31%) of very low density lipoprotein (VLDL) particles. Changes in composition of VLDL were present but less evident. In contrast to this, acute exercise did not induce significant changes in the average concentration of individual low-density lipoprotein (LDL) subfractions. However, changes in dense LDL [density (d) > 1.044 g.ml-1] concentration were significantly correlated to changes in serum TG: a reduction of dense LDL occurred in subjects with large reductions in serum TG. In addition, LDL composition changed significantly. Immediately (1 h) after exercise the TG content of all LDL subfractions was reduced. These reductions were significant in large (d = 1.006-1.037 g.ml-1) and small LDL (1.044-1.063 g.ml-1). It can be concluded therefore from our study that acute exercise primarily altered the composition of LDL subfractions while their concentration remained stable.

Association between heart rate and atherogenic blood lipid fractions in a population. The Tromsø Study

BACKGROUND

Prospective epidemiological studies indicate that elevated heart rate may carry increased risk for coronary heart disease. Little is known about the relation between heart rate and serum lipid and lipoprotein concentrations in the general population.

METHODS AND RESULTS

We assessed anthropometric and life-style determinants of heart rate and examined the association between heart rate and serum lipid and lipoprotein concentrations in a cross-sectional study of 9,719 men and 9,433 women 12-59 years old. Stratified and multivariate analyses were used to detect possible modification of effect and to control for confounding variables. Heart rate was positively associated with male sex and smoking, decreased with body height and physical activity, and showed a U-shaped relation to body mass index. In both sexes, there was a significant progressive increase in age-adjusted levels of total cholesterol, non-high density lipoprotein (HDL) cholesterol, and triglycerides and a decrease in HDL cholesterol with heart rate. Men with heart rate greater than 89 beats per minute had 14.5% higher non-HDL cholesterol and 36.3% higher triglyceride levels than men with heart rate less than 60 beats per minute. The corresponding differences in women were 12.5% and 22.2%. The associations remained significant when anthropometric and life-style factors were controlled for. The slopes relating total and non-HDL cholesterol level to heart rate were steeper with advancing age.

CONCLUSIONS

Increases in heart rate correlate with higher levels of atherogenic serum lipid fractions in the general population. Alterations in aortic impedance and/or autonomic influences may underlie these associations.