[Epidemiology of running-induced complaints of joggers. Berne runner study '84]

In a sample of 4358 male joggers (= 76.1% of the participants in a popular 16 km race in Berne 1984) 45.8% of joggers sustained running-related injuries during a one year period. 14.2% sought medical help and 2.3% missed work because of jogging injuries. The most important factor in running-related injuries is (average) weekly mileage. Joggers see the doctor less often than the reference population, although this difference cannot be attributed directly to jogging. Increasing mileage is associated with more frequent visits to the doctor, and this increased frequency of medical consultations is due entirely to jogging-related injuries.

Jogging: cardiovascular benefits and risks

The cardiovascular benefits and risks of jogging are frequently debated. This article presents information on the effects of jogging and other aerobic exercise on heart rate, cardiac output, tissue oxygen consumption and blood pressure. The indirect effects of jogging on cardiac risk factors, such as serum lipids, blood clotting and glucose metabolism, are discussed. Along with the positive outcomes from jogging, the risks to the cardiovascular system are presented. These risks include a sudden drop in blood pressure at the cessation of intense jogging, cardiac arrhythmias and ischemia. The primary care nurse practitioner can play an important role in prescribing a level of exercise that is safe and will enhance physical fitness, particularly cardiovascular fitness. Guidelines for prescribing an exercise program for a variety of patient populations are reviewed, and the need for exercise monitoring by the individual is stressed.

The effect of exercise on non-restricted caloric intake in male joggers

This study examined the effects of both increasing and decreasing normal energy expenditure over periods of one week on the self-reported caloric intake of seven male joggers (22-27 years). The three levels of energy expenditure were: no exercise, regular exercise and double exercise. Despite significant difference in energy expenditure across conditions, self-reported caloric intake did not differ significantly, suggesting that energy intake was not affected by short-term changes in energy expenditure.

Profound hypophosphataemia in patients collapsing after a "fun run"

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Special ergometric techniques and weight reduction

Several physiological and psychological benefits can be achieved with exercise training provided an adequate exercise threshold is reached. In recommending exercise regimens to obese individuals, it is important to consider the exercise intensity, frequency, and duration that is most likely to lead to the desired benefits of exercise training. The special problems that some obese individuals may encounter with exercise training should also be considered. Walk/jog and stationary cycling are the two most commonly recommended modes of exercise. Aquatic exercise, due to the buoyancy and thermal properties of water, may be especially suitable as a method of exercise for obese individuals. In addition to swimming, cycling exercise and aerobic dance can be performed in a water environment.

The effects of internal versus external information processing on symptom perception in an exercise setting

The purpose of our study was to determine the effects of internal versus external attentional focus on symptom perception and performance in an exercise setting. Fifteen introductory psychology undergraduates ran 1 mile under each of three experimental conditions: "word-cue," in which subjects were required to focus externally by listening for a target word heard repeatedly over headphones; "breathing," in which subjects were directed to attend to their own breathing and heart rate; and a control. Results indicated that participants reported significantly less symptomatology, particularly exercise-relevant symptoms, in the word-cue condition than in the breathing or control conditions. The findings are discussed with reference to previous theory in this area, and methodological differences between this and earlier research are delineated.

Exercise in coronary heart disease

Population levels of habitual activity have probably contributed to both the recent epidemic of cardiovascular disease and its waning. Evidence supporting the exercise hypothesis can be drawn from comparisons of individuals with differing levels of occupational and leisure activity. Both suggest that regular, endurance-type activity may halve the incidence of cardiac morbidity and mortality. This is an important prophylactic benefit, although Bradford Hill's criteria of a causal association have yet to be fully satisfied. Following the onset of clinical disease, both uncontrolled and randomised controlled trials suggest that progressive exercise rehabilitation improves prognosis by a useful 20 to 30%, but formal statistical proof is again difficult for technical reasons. Although over-enthusiastic vigorous physical activity can cause an immediate rise of cardiovascular events, this disadvantage is substantially outweighed by long term gains from regular physical activity. Classical epidemiology has proven its case by the experimental step of removing exposure to the causal agent. It is difficult to carry out such an analysis linking physical activity with the recent epidemic of ischaemic heart disease, although the recent waning of the disease may be attributed in part to an increase of habitual physical activity in many western nations. Evidence linking exercise to the prevention of clinical disease ('secondary prevention') is derived from large scale surveys of groups with supposed differences in occupational activity, athletic participation, active leisure pursuits or overall lifestyle. The majority of occupational comparisons have shown advantages to active workers in terms of deaths from cardiac disease, sudden death, cardiac morbidity, ECG abnormalities, and cardiac abnormalities at postmortem. However, concerns have been raised with regard to the accuracy of job classification, the intensity of occupational activity relative to active leisure, the adequacy of disease classification, and confounding influences due to differences of social class, stress and potential alienation. Studies comparing athletes and non-athletes have been faulted on grounds of initial selection for sport by body-build and uncertainties regarding continuing differences of endurance activity between recognised university athletes and their classmates. In general, no advantage of life expectancy has been seen in athletes, Karvonen and associates reported a 4 to 5 year advantage of longevity in Finnish cross-country skiing champions, although this might be attributable to other facets of their lifestyle.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of exercise and physical fitness on the pituitary-thyroid axis and on prolactin secretion in male runners

The effects of acute exercise and thyrotropin-releasing hormone on the pituitary-thyroid axis were examined in men placed into three well-defined categories of physical fitness. There were 20 sedentary men, 22 joggers (running four to 20 miles per week) and 18 marathoners (running 30 to 100 miles per week) who participated. During treadmill exercise, the mean VO2 max differed among all groups, being 38.5, 45.0, and 60.3 mL/kg . min in the sedentary, jogger, and marathon groups, respectively. Serum was obtained before, immediately after, and one hour after exercise for measurement of thyroxine (T4), triiodothyronine (T3), reverse T3, thyrotropin (TSH), and prolactin. Basal values of all hormones did not differ among the groups. Maximal short-term treadmill exercise produced no change in serum T4, T3, reverse T3, or TSH. Prolactin rose significantly by a similar amount in all three subject groups. On a separate day, ten individuals from each group received thyrotropin releasing hormone (TRH; 500 micrograms IV). Neither the peak TSH response nor the total TSH secreted during two hours after TRH differed among groups. The mean total prolactin secretion in the joggers and marathoners was 48% and 45% greater, respectively, than in the sedentary men. Five subjects in each group also underwent a TRH test immediately postexercise. Similar to the results on the nonexercise day, the integrated TSH response to TRH was similar in all three groups, whereas the integrated PRL response to TRH was increased by 52% and 78% in the two conditioned groups. Post-TRH sera from one subject in each group were fractionated on a Sephadex G-100 column.(ABSTRACT TRUNCATED AT 250 WORDS)

Psoas muscle hypertrophy: mechanical cause for "jogger's trots?"

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Physical fitness in aging men

Of 56 middle-aged male joggers (mean age 43.3 yr), 38 were measured for maximal oxygen uptake (VO2max) and 18 for cardiac output at a heart rate of 170 bpm (Q170). Each Q170 was divided by subject body surface area to yield cardiac index (CI170). A treadmill protocol was used to elicit maximal exercise during measurement of VO2max. The bicycle ergometer was employed when measuring Q170. For maximal exercise, termination was upon subject-declared fatigue. In subjects measured for VO2max, heart rate at 3.5 miles/h and 5% treadmill grade (HRsubmax) as well as heart rate at maximal exercise (HRmax) were noted. Heart rates were monitored electrocardiographically. A modified Douglas bag technique was applied when sampling expired air for determination of VO2max. Carbon dioxide rebreathing was used to estimate Q170. Data were grouped according to age (43 yr and older; 42 yr and younger). There were significant (P less than 0.05) positive relationships between VO2max and HRmax and between HRsubmax and age. Significant negative relationships existed between HRmax and HRsubmax, and between CI170 and 10 km running time. There were no significant differences (P greater than 0.05) between means achieved by the age groups. The overall mean for VO2max was 43.36 ml/kg per min and for Q170 33.53 1/min. Findings suggest that men who remain physically active retain youthful characteristics of cardiorespiratory function.

Health locus of control of joggers and nonexercisers

To gain a better understanding of why some people engage in regular leisure-time physical exercise while others remain sedentary, the Multidimensional Health Locus of Control scale was distributed to 123 younger joggers and 93 nonexercisers. Analysis of the responses indicated that the joggers scored significantly higher on the internal subscale than did the nonexercisers. No significant differences were found on the Chance and Powerful Others subscales. The disparity of these results from those of other studies of the relationship between locus of control and exercise suggest that an exercise specific locus of control scale needs to be developed. The confound of age with exercise and locus of control requires clarification.

Insulin sensitivity in joggers: evaluation by mini-dose insulin infusion test

Insulin sensitivity in seven joggers was evaluated by a minidose insulin infusion test. The results were compared to those of 22 healthy nonjoggers with a mean body weight within +/- 115% of ideal body weight. The mean increase over base line of the individual steady-state insulin levels were delta 25 microU/ml (range 15-42 microU/ml) for controls and delta 16 microU/ml (range 11.2-23.4 microU/ml) for the joggers. The smaller incremental rise in insulin concentration most likely is due to an increased insulin turnover. The declines in glucose concentrations from 10 min after the infusion began to a nadir were similar in controls (28 +/- 2.4 mg/dl) and in the joggers (33.7 +/- 3.6 mg/dl). However, the insulin sensitivity index, defined as the rate of plasma glucose decline divided by the increment rise in insulin, was clearly higher in the joggers (0.098 +/- 0.009 vs 0.057 +/- 0.005, P less than 0.05). We conclude that the joggers as a group are more sensitive to insulin. The simplicity of a mini-dose insulin infusion should be useful in longitudinal studies where the effect of physical training on insulin sensitivity may be of interest.

Jogging in middle age

The risks and possible cardiovascular benefits of beginning a programme of jogging in middle age are critically reviewed. A lifelong habit of vigorous exercise results in lower incidence rates of ischaemic heart disease. There is, however, no direct evidence that the same is true when sedentary middle-aged people decide to begin exercise. Exercise can have a beneficial effect on the risk factors for ischaemic heart disease but whether this reduces the likelihood of death from ischaemic heart disease remains unproven. There are approximately 12 sudden deaths per 100 000 male joggers in the USA attributable to jogging annually, while almost a third of all joggers report a musculoskeletal injury in a 12-month period.

Exercise-associated solar purpura in an atypical location

Solar purpura localized to the malar region occurred in a 41-year-old jogger after a six mile run. This eruption is another example of the dermatoses experienced by athletes.

Jogger's fracture and other stress fractures of the lumbo-sacral spine

The posterior rings of the lower lumbo-sacral vertebrae are subject to stress fractures at any part - pedicle, pars, or lamina. The site of fracture is apparently determined by the axis of weight bearing. The three illustrative clinical examples cited include a jogger with a laminar fracture, a ballet dancer with pedicle fractures, and a nine-year-old boy with fractures of pars and lamina. Chronic low back pain is the typical complaint with stress fractures of the lower lumbo-sacral spine. Special imaging techniques are usually needed to demonstrate these lesions, including vertebral arch views, multi-directional tomography, and computed tomography (CT).