Effects of exercise intensity on flow mediated dilation in healthy humans.

Previous studies have demonstrated conflicting results on the effects of acute exercise on FMD. The aim of the study was to examine brachial artery FMD before and after 3 bouts of acute exercise performed at different intensities. 10 healthy males (mean±SD age: 22±1 years) completed 30 min of cycling at 50, 70 and 85% maximal heart rate (HRmax). Brachial artery FMD and the shear rate area-under-the-curve (cuff deflation to peak dilation; SRAUC) were assessed pre- and immediately post-exercise using high-resolution echo-Doppler. A generalized estimating equation (GEE) analysis was used to estimate the effect magnitudes of exercise intensity and time (pre/post) on FMD, whilst controlling for the influence of baseline diameter and SRAUC. Both baseline diameter and SRAUC were elevated by exercise. With covariate-control of these variables, the decrease in brachial artery FMD was negligible after exercise at 50% HRmax (6.3±2.6 vs. 5.9±2.5%; 95%CI for difference: - 0.59-1.34%) with larger decreases in FMD after exercise at 70% (6.1±1.8 vs. 4.7±1.9%; 95%CI for difference: 0.08-2.58%) and at 85% HRmax (6.6±1.6 vs. 3.6±2.2%; 95%CI: 0.41-5.42%). In conclusion, even after accounting for exercise-mediated changes in shear and baseline diameter, our data indicate that a negative relationship exists between exercise intensity and FMD.

Effects of environmental heat stress (35 degrees C) with simulated air movement on the thermoregulatory responses during a 4-km cycling time trial.

The aim of the present investigation was to examine the influence of environmental heat stress (35 degrees C) on 4-km cycling time trial performance using simulated environmental conditions and facing air velocities that closely reflect competitive situations. Nine competitive cyclists (age 34 +/- 5 years, maximal oxygen uptake 61.7 +/- 8.6 ml . kg (-1) . min (-1)) completed a simulated 4-km cycling time trial in laboratory ambient temperatures (dry bulb temperatures) of 35 degrees C and 13 degrees C (relative humidity 60 %, air velocity 5.6 m/s). Mean performance time was reduced in 35 degrees C (390.1 +/- 19.6 s) compared to 13 degrees C (382.8 +/- 18.2 s) (95 % CI of difference = 4.0 to 10.6 s; p < 0.01). This was consistent with a decline in mean power output throughout the duration of exercise in 35 degrees C compared with 13 degrees C (p < 0.01). Mean skin temperature and mean body temperatures were elevated at rest and throughout the duration of exercise in 35 degrees C (p < 0.01). A higher level of muscle temperature was also observed at the onset and cessation of exercise in 35 degrees C (p < 0.01). The rate of heat storage (35 degrees C, 413.6 +/- 130.8 W . m (-2); 13 degrees C, 153.1 +/- 112.5 W . m (-2)) representative of the entire 4-km time trial was greater in the heat (p < 0.01). When expressed per kilometre, however, difference in the rate of heat storage between conditions declined during the final kilometre of exercise (p = 0.06). We conclude that the current decrements in self-selected work-rate in the heat are mediated to some extent through afferent feedback arising from changes in heat storage at rest and during the early stages of exercise which serve to regulate the subsequent exercise intensity in attempt to preserve thermal homeostasis.

Effects of dietary carbohydrate on delayed onset muscle soreness and reactive oxygen species after contraction induced muscle damage.

BACKGROUND: Delayed onset muscle soreness (DOMS) occurs after unaccustomed exercise and has been suggested to be attributable to reactive oxygen species (ROS). Previous studies have shown increased ROS after lengthening contractions, attributable to invading phagocytes. Plasma glucose is a vital fuel for phagocytes, therefore carbohydrate (CHO) status before exercise may influence ROS production and DOMS. OBJECTIVE: To examine the effect of pre-exercise CHO status on DOMS, ROS production, and muscle function after contraction induced muscle damage. METHOD: Twelve subjects performed two downhill runs, one after a high CHO diet and one after a low CHO diet. Blood samples were drawn for analysis of malondialdehyde, total glutathione, creatine kinase, non-esterified fatty acids, lactate, glucose, and leucocytes. DOMS and muscle function were assessed daily. RESULTS: The high CHO diet resulted in higher respiratory exchange ratio and lactate concentrations than the low CHO diet before exercise. The low CHO diet resulted in higher non-esterified fatty acid concentrations before exercise. DOMS developed after exercise and remained for up to 96 hours, after both diets. A biphasic response in creatine kinase occurred after both diets at 24 and 96 hours after exercise. Malondialdehyde had increased 72 hours after exercise after both diets, and muscle function was attenuated up to this time. CONCLUSIONS: Downhill running resulted in increased ROS production and ratings of DOMS and secondary increases in muscle damage. CHO status before exercise had no effect.

A comparison of the immediate effects of moderate exercise in the late morning and late afternoon on core temperature and cutaneous thermoregulatory mechanisms.

Twelve healthy male subjects each undertook two bouts of moderate exercise (70% VO2max for 30 minutes) in the morning (08:00) and late afternoon (18:00) at least 4 days apart. Measurements were made of heart rate, core (rectal) temperature, sternum skin temperature, and forearm skin blood flow during baseline conditions, during the bout of exercise, and throughout a 30-minute recovery period. Comparisons were made of the changes of heart rate, temperature, and skin blood flow produced by the exercise at the two times of day. Student t tests indicated that baseline values for core temperature (37.15 degrees C +/- 0.06 degrees C vs. 36.77 degrees C +/- 0.06 degrees C) and sternum temperature (33.60 degrees C +/- 0.29 degrees C vs. 32.70 degrees C + 0.38 degrees C) were significantly (p < .05) higher in the late afternoon than the early morning. Two-way analysis of variance (ANOVA) indicated that the increases in core and sternum temperatures during exercise were significantly less (p = .0039 and .0421, respectively) during the afternoon bout of exercise compared with the morning, even though the work loads, as determined by changes in heart rate, were not significantly different (p = .798) at the two times of testing. There were also tendencies for resting forearm skin blood flow to be higher in the afternoon than in the morning and for exercise to produce a more rapid rise in this variable in the afternoon. The possible mechanisms producing these responses to exercise are discussed in terms of those that are responsible for the normal circadian rhythm of core temperature. It is concluded that the body's ability to remove a heat load is less in the early morning, when the circadian system is in a "heat gain" mode, than in the late afternoon, when heat gain and "heat loss" modes are balanced more evenly.

Lessons from the Oslo Study Diet and Anti-smoking Trial: a qualitative study of long-term behaviour change.

The aim of this study was to identify factors associated with sustainable behaviour change among persons at increased risk for future cardiovascular disease. A qualitative approach based on focus group interviews was used. Twenty-five men aged 62-71 years who participated in the Oslo Study Diet and Anti-smoking Trial were interviewed in four focus groups. The study identified five categories of factors linked to the process of lifestyle changes: the doctor-patient relationship, significant others, motivators, barriers, and empowerment. A strong personal attachment to the principal investigator of the Oslo Study was revealed. The relationship was described as friendly and supportive. The family based approach and the impact of spouses, in particular, was emphasized by the participants. Somatic symptoms and fear often acted as motivators to behavioural change. Individual feedback was also identified as an important motivator. Psychological resistance to external pressure, concerns regarding behaviour change, and benefits from current (unhealthy) behaviour were identified as barriers. Participants reported a process of empowerment and personal control as an important element of sustainable change. The importance of the unique relationship with a certain provider has implications for future healthcare planning. This factor may also limit the external validity of studies of human behaviour.

Teaching preventive cardiology: the consultation clinic.

Atherosclerotic heart disease is the principal cause of death in the United States and other industrial societies. Three major risk factors for developing coronary artery disease (hypertension, hypercholesterolemia, and smoking) are frequently seen in family practice patients. It is therefore important for family physicians to be able to assess an individual patient's overall heart disease risk and provide advice and counseling to reduce that risk. This article describes a teaching-consultation clinic in which family practice residents learn to assess cardiac risk in patients and develop counseling skills to manage that risk. The role of the family physician in relation to the cardiologist is also discussed. Medical Subject Headings (MeSH): preventive medicine, cardiology, residency.

Preventive medicine matrix as a residency curriculum development tool.

Preventive medicine has become a central issue in health care reform, but how best to teach and implement health promotion/disease prevention (HP/DP) in clinical practice is still undefined. This article describes the Preventive Medicine Matrix as a tool to help organize the complex and broad area of prevention into a workable curriculum for residency programs. The matrix is divided into life-cycle periods and HP/DP curricular topics. Using the matrix, a program can assess the areas it is addressing well and those that require emphasis. A major strength of the matrix is its flexibility, which allows modifications for the different needs of individual programs.

Effects of acute exercise on lymphocyte subsets and metabolic activity.

Lymphocyte subsets, their responsiveness to mitogen and their capacity for glutamine oxidation and glycolysis were assessed in seven subjects before and after an acute bout of interval exercise, the purpose being to establish whether exercise is associated with alterations in lymphocyte metabolic capacities. The subjects exercised at 112% of their maximal work capacity (as determined by pre-test) on a treadmill and performed 25 repeat tests, each of 1 min duration interrupted by 2 min rest periods. Venous blood samples were taken at rest and 3 min following completion of exercise. Acute exercise was associated with significant decreases in the percentage of T- (p < 0.01) and B-cells (p < 0.01) and an increase in the percentage of NK-cells (p < 0.05). These changes were accompanied by a significant decrease in the responsiveness of peripheral blood lymphocytes to the mitogen concanavalin A (p < 0.05). Acute exercise was also associated with profound changes in the metabolic capacities of peripheral blood lymphocytes: rates of 14CO2 production from [U-14C]glutamine (19%: p < 0.05) and lactate (27%: p < 0.05) production were increased significantly in response to interval exercise. Linear regression analysis revealed significant correlation between the exercise-mediated changes (%) in T- and NK-cells and changes (%) in both lymphocyte responsiveness to concanavalin A and metabolic capacity, particularly glutamine oxidation to CO2. One interpretation of these data is that acute exercise promotes a redistribution in lymphocyte subsets, and that it is this redistribution that is the basis of both the impairment in lymphocyte responsiveness to mitogens and the increase in lymphocyte metabolic capacity, especially glutamine oxidation.(ABSTRACT TRUNCATED AT 250 WORDS)

Accuracy of patient recall and chart documentation of falls.

BACKGROUND: This 1-year prospective study examined the accuracy of patient recall of falls and fall injuries and completeness of chart documentation of these events. METHODS: One hundred ambulatory geriatric family practice patients reported falls weekly by postcard with telephone call follow-up. On a final postcard they reported their recall of falls and fall injuries in the preceding 3-, 6-, and 12-month periods. Patient charts were reviewed for fall documentation. RESULTS: For the 3-, 6-, and 12-month periods, respectively, 31 percent, 44 percent, and 89 percent of participants who had reported a fall recalled at least one fall. Sixty-eight percent of participants who had reported an injury recalled one at the year's end. The positive predictive value of recalling a fall was 92 percent and of recalling a fall injury was 72 percent for the 1-year period. Only 10 of 56 (18 percent) reported falls were documented in the patient's chart. CONCLUSIONS: Patients recalled falls and injuries in the previous 12 months well, but they were less accurate for recall periods of 3 and 6 months. Few reported falls were documented by the patient's physician. Awareness of falls can be increased by asking the patient about falls during the previous year and by documenting all reported and recalled falls.

Results of a work-site educational and screening program for hypertension and cancer.

Cardiovascular disease and cancer account for 68% of deaths in the United States each year. Office-based screening efforts to detect early or asymptomatic disease have been modestly successful at best, as neither patients nor physicians routinely follow American Cancer Society guidelines. The work site, representing a captive group of patients, is an alternative screening site. Eight hundred eighty-eight employees at 10 work sites were screened for hypertension and six types of cancer (oral, breast, rectal, colon, prostate, and testicular). Fifty-one employees with new onset or poorly controlled hypertension were identified, along with two early cancers (rectal, breast) and four malignant precursors. Potential dollar savings to employee, employer, and society were three times the cost of the screening program. Screening at the work site represents an efficient, cost-effective approach for the early detection of hypertension and cancer.

Prevalence and types of injuries in aerobic dancers.

A sample of 726 aerobic dancers was surveyed by questionnaire to document the prevalence, types, and severity of injuries experienced. Data were gathered on demographics, exercise behavior, and environmental conditions during a 1 week period. Most of the subjects (66%) engaged in aerobic dance classes at least every other day, with a mean exercise time of 195 minutes per week. Twenty-eight percent of the subjects had been exercising 1 to 2 years, and 26% had been exercising 2 years or longer. Forty-nine percent of the subjects reported a history of at least one injury related to aerobic dancing. Most of the injuries were to the shin (24.5%), lower back (12.9%), and ankle (12.2%). Among those subjects injured, 23% reportedly saw a physician because of their injury. The frequency with which subjects exercised was associated with a history of injury. Subjects who exercised fewer than four times per week reported fewer injuries (43%) than those who exercised four times per week (60%) or more (66%). This study is a first step toward providing data to help physicians counsel aerobic dancers regarding injury prevention.

Nuchal cord: an unusual manifestation.

This case report describes an unusual manifestation of nuchal cord--significant fetal neck compression without compromised cord blood flow. The physical signs and clinical outcome of this infant are reported.

Effects of clorazepate on breathlessness and exercise tolerance in patients with chronic airflow obstruction.

Five patients with severe chronic lung disease were given placebo or 7.5 mg of clorazepate, a benzodiazepine, at bedtime for two weeks using a double-blind cross-over study design. Exercise tolerance, arterial blood gases, pulmonary function tests, self-rated breathlessness, and self-administered depression and anxiety scores were similar during drug treatment, placebo treatment, and washout periods. Higher doses of clorazepate were not tolerated by three of five patients. Nonanxious patients with chronic lung disease seem not to benefit subjectively or objectively from a low-dose benzodiazepine regimen.

Implementation of recommended health maintenance activities in geriatric care.

To determine the extent to which health screening and preventive measures are actually documented in family practice, a random sample of 216 charts of established patients over 65 in seven practices was audited. Overall, a high rate of documentation (greater than 95%) was observed for blood pressure measurement. Intermediate rates of documentation (35% to 75%) were observed for oral cavity examination, smoking history, and skin examination. Low rates (less than 30%) were present for tetanus immunization, influenza immunization, stool occult blood testing, visual screening, hearing screening, mental status testing, social support description, and discussion of care preferences (living will). Several diagnoses for which screening was infrequently documented were recorded at rates approaching expected community prevalence figures, a finding that suggests widespread performance of informal or undocumented health screening in these practices. Recommended measures to increase the performance and documentation of preventive care include changes in the medical record, alterations in reimbursement, and delegation to nonphysician office staff.