Groningen active living model (GALM): stimulating physical activity in sedentary older adults; first results.

BACKGROUND: A significant proportion of older adults in The Netherlands does not regularly participate in leisure-time physical activity. The Groningen Active Living Model (GALM) was developed to change this situation for the better. In this article the first results with respect to the validation of the model are presented. METHODS: We obtained cross-sectional data from a sample of 392 potential participants. Scores on the potentially causal variables (self-efficacy, social support, perceived fitness, and enjoyment) and the stages of change give a first indication of the potential validity of the GALM behavioral change model. RESULTS: Seventeen percent of the subjects could be categorized as in the precontemplation stage, 42% in the contemplation/preparation stage, and 39% in the action/maintenance stage. Data with respect to stages of change were missing for 2% of the subjects. Scores on all potentially causal variables rose significantly from the precontemplation to the action/maintenance stage. Discriminant analysis resulted in a canonical correlation of 0.58 between the precontemplation and the contemplation/preparation stages and 0.59 between the contemplation/preparation and action/maintenance stages; respectively, 82.6 and 78.3% of the subjects had been classified correctly. CONCLUSIONS: The results found in this study support our hypothesis, as described in the conceptual theory of the GALM behavioral change model. For a more comprehensive validation of the model's action theory and conceptual theory, follow-up measurements are required.

Differential effects of high-frequency versus low-frequency exercise training in rehabilitation of patients with coronary artery disease.

OBJECTIVES: We sought to study the influence of frequency of exercise training during cardiac rehabilitation on functional capacity (i.e., peak oxygen consumption [VO2] and ventilatory anaerobic threshold [VAT]) and quality of life (QoL). BACKGROUND: Although the value of cardiac rehabilitation is now well established, the influence of the different program characteristics on outcome has received little attention, and the effect of frequency of exercise training is unclear. Functional capacity is regularly evaluated by peak VO2 but parameters of submaximal exercise capacity such as VAT should also be considered because submaximal exercise capacity is especially important in daily living. METHODS: Patients with coronary artery disease (n = 130, 114 men; mean age 52 +/- 9 years) were randomized to either a high- or low-frequency program of six weeks (10 or 2 exercise sessions per week of 2 h, respectively). Functional capacity and QoL were assessed before and after cardiac rehabilitation. Global costs were also compared. RESULTS: Compared with baseline, mean exercise capacity increased in both programs: for high- and low-frequency, respectively: peak VO2 = 15% and 12%, Wmax = 18% and 12%, VAT = 35% and 12% (all p < 0.001). However, when the programs were compared, only VAT increased significantly more during the high-frequency program (p = 0.002). During the high-frequency program, QoL increased slightly more, and more individuals improved in subjective physical functioning (p = 0.014). We observed superiority of the high-frequency program, especially in younger patients. Mean costs were estimated at 4,455 and 2,273 Euro, respectively, for the high- and low-frequency programs. CONCLUSIONS: High-frequency exercise training is more effective in terms of VAT and QoL, but peak VO2 improves equally in both programs. Younger patients seem to benefit more from the high-frequency training.

A Dutch version of the Social Support for Exercise Behaviors Scale.

We studied the reliability of a Dutch version of the Social Support for Exercise Behaviors Scale, originally developed by Sallis, Grossman, Pinski, Patterson, and Nader, using a sample of 461 older adults between 55 and 65 years of age. Cronbach alpha for the three subscales was calculated, respectively, as .69, .71, and .26, which are lower than the alphas reported in the original study. This may be due to the cultural differences between The Netherlands and the United States and differences between the samples of the two studies.

The Groningen Enjoyment Questionnaire: a measure of enjoyment in leisure-time physical activity.

The purpose of this study was to develop a short and easily used questionnaire to measure enjoyment in leisure-time physical activity. The first part of the study involved the questionnaire's composition. A set of 30 positively formulated potential items was generated and subsequently completed by 59 subjects. We used these results to trim the questionnaire to 10 items. In the second part of the study, the questionnaire was administered to 82 subjects and research was done into reliability and validity. The results indicate that the Groningen Enjoyment Questionnaire can be considered reliable and valid.

Groningen Active Living Model (GALM): stimulating physical activity in sedentary older adults.

BACKGROUND: A significant number of Dutch older adults can be considered sedentary when it comes to regular participation in leisure-time physical activity. Sedentariness is considered a potential public health burden-all the more reason to develop a strategy for stimulating older adults toward becoming more involved in leisure-time physical activity. The Groningen Active Living Model (GALM) is a behavioral change strategy for stimulating participation in leisure-time physical activity. METHODS: The GALM strategy is based on a process model of behavioral change in which behavioral change is seen as a multidimensional and dynamic process. The strategy has three phases: recruitment, introduction, and follow-up, and lasts 18 months. RESULTS: Preliminary results indicate that, up until the summer of 1998, about 4000 older adults were participating in 76 local GALM projects. Further research will be done to assess the validity of the model and its effects on the leisure-time physical activity pattern, ADL performance, and health in newly active older adults. CONCLUSIONS: The GALM strategy is a feasible strategy for stimulating leisure-time physical activity participation on a large-scale basis. The strategy is being implemented in The Netherlands on a nationwide basis.

Effect of high- versus low-frequency exercise training in multidisciplinary cardiac rehabilitation on health-related quality of life.

BACKGROUND: The authors examined the importance of the frequency of aerobic exercise training in multidisciplinary rehabilitation in improving health-related quality of life in the short run in patients with documented coronary artery disease. METHODS: Patients (114 males and 16 females; age range, 32-70 years) were randomized into either a high-frequency or a low-frequency exercise training program (10 versus 2 sessions per week, respectively) as part of a 6-week multidisciplinary cardiac rehabilitation program. The General Health Questionnaire and the RAND-36 were used to assess changes in psychological distress and subjective health status. RESULTS: After 6 weeks, high-frequency patients reported significantly more positive, change in "psychological distress" (P < 0.05), "mental health" (P = 0.05), and "health change" (P < 0.01), than low-frequency patients. Apart from changes in mean scores, individual effect sizes indicated that a significantly greater percentage of high-frequency patients experienced substantial improvements in "psychological distress" (P < 0.01), "physical functioning" (P < 0.05), and "health change" (P < 0.05), compared with low-frequency patients. In addition, deterioration of quality of life was observed in a considerable number of high-frequency patients (ranging from 1.7% to 25.8% on the various measures). CONCLUSIONS: The frequency of aerobic exercise has a positive, independent effect on psychological outcomes after cardiac rehabilitation. However, this benefit after high-frequency rehabilitation appears to be limited to a subgroup of patients. Further investigation is required to identify these patients. Results provide input into recent controversies regarding the role of exercise training in cardiac rehabilitation.

Change in self-efficacy during cardiac rehabilitation and the role of perceived overprotectiveness.

Self-efficacy (SE) is an important outcome following cardiac rehabilitation (CR) when claiming benefits to patients and improving existing programs. This study evaluated change in SE during 6 weeks of multidisciplinary CR with either a high or low-frequency exercise training program. The role of overprotectiveness of the spouse, as it potentially counteracts improvement in SE, was examined. Coronary patients (n = 114) were randomized into both types of program. Overprotectiveness (patient perception) was assessed prior to rehabilitation. Self-efficacy in the domains controlling symptoms (SE-CS) and maintaining function (SE-MF), were assessed prior to and immediately after rehabilitation. Three findings pertain to program improvement: (1) As predicted, the low-frequency program enhanced SE-CS more than the high-frequency program, suggesting that experiencing success in daily activities and active engagement of the patient seem more decisive factors in improving SE than the frequency of exercise. (2) Changes in SE in both programs fell short of clinical meaning, suggesting the need to use self-efficacy theory more vigorously. (3) Overprotectiveness significantly predicted adverse change in SE in the high-frequency program, suggesting the need to include counseling for cardiac couples in CR when applicable.

Impairment of exercise capacity and peak oxygen consumption in patients with mild left ventricular dysfunction and coronary artery disease.

AIMS: Most studies in chronic heart failure have only included patients with marked left ventricular systolic dysfunction (i.e. ejection fraction < or =0.35), and patients with mild left ventricular dysfunction are usually excluded. Further, exercise capacity strongly depends on age, but age-adjustment is usually not applied in these studies. Therefore, this study sought to establish whether (age-adjusted) peak VO2 was impaired in patients with mild left ventricular dysfunction. METHODS: Peak VO2 and ventilatory anaerobic threshold were measured in 56 male patients with mild left ventricular dysfunction (ejection fraction 0.35-0.55; study population) and in 17 male patients with a normal left ventricular function (ejection fraction >0.55; control population). All patients had an old (>4 weeks) myocardial infarction. By using age-adjusted peak VO2 values, a 'decreased' exercise capacity was defined as < or = predicted peak VO2 - 1 x SD (0.81 of predicted peak VO2), and a severely decreased exercise capacity as < or = predicted peak VO2 - 2 x SD (0.62 of predicted peak VO2). RESULTS: Patients in the study population (age 52+/-9 years; ejection fraction 0.46+/-0.06) were mostly asymptomatic (NYHA class I: n=40, 76%), while 16 patients (24%) had mild symptoms, i.e. NYHA class II. All 17 controls (age 57+/-8 years) were asymptomatic. Mean peak VO2 was lower in patients with mild left ventricular dysfunction (23.6+/-5.7 vs 27.1+/-4.6 ml x min(-1) x kg(-1) in controls, P<0.05). In 75% of the study population patients (n=42) age-adjusted peak VO2 was decreased (NYHA I/II: n=29/13) and in 18% of them severely decreased (n=10; NYHA I/II: n=6/4). In contrast, only three patients (18%) in the control population had a decreased and none a severely decreased age-adjusted peak VO2. CONCLUSION: In patients with mild left ventricular dysfunction, who have either no or only mild symptoms of chronic heart failure, a substantial proportion has an impaired exercise capacity. By using age-adjustment, impairment of exercise capacity becomes more evident in younger patients. Patients with mild left ventricular dysfunction are probably under-diagnosed, and this finding has clinical and therapeutic implications.

Training effects on peak VO2, specific of the mode of movement, in rehabilitation of patients with coronary artery disease.

Training effects on peak oxygen consumption (VO2), specific to the mode of movement, are well-known in exercise training of young, healthy adults. However, these specific training effects were never studied in patients with coronary artery disease, but may be important in the evaluation of training effects of cardiac rehabilitation programs. Exercise training programs dominated by, for example, cycling might improve peak VO2, measured during cycling, more than during treadmill testing. Therefore, the effects of an exercise training program dominated by cycling and of a program with both cycling and walking/jogging during a 6-weeks cardiac rehabilitation program were evaluated on both cycle ergometer and treadmill. Male patients (aged between 35 and 70 years) with coronary artery disease (history of myocardial infarction and/or angina pectoris and/or coronary artery bypass surgery) were randomly assigned to either a program dominated by cycling (Group I: n=18,mean age 53+/-6.7) or a program with both cycling and jogging (Group II: n=20, mean age 48+/-9.1). Before and after the program peak VO2 was measured on both cycle ergometer and treadmill. At baseline peak VO2 on treadmill was significantly greater than on cycle ergometer in both groups. Peak VO2 (both cycle and treadmill) increased highly significantly during both programs; in group I the increase of peak VO2 on cycle ergometer was greater than on treadmill (respectively, 28.1% versus 18.8%; p<0.05), in contrast to group II (respectively, 22.8% and 16.6%; n.s.). As a result, the difference between peak VO2 on treadmill and cycle ergometer decreased significantly more during the program in group I (p<0.05). These results suggest specific training effects in patients with coronary artery disease and should be considered outcome assessment and exercise prescription of cardiac rehabilitation programs.

Ten-metre walk, with or without a turn?

OBJECTIVE: To compare results obtained using different procedures to measure 10-metre walking time. DESIGN: Walking was timed over a straight 10 m, and over 5 m with return. Further, the time taken to turn was measured directly. SETTING: Rehabilitation department of a university hospital. SUBJECTS: Patients who had walking disability after stroke. RESULTS: In the group of 43 patients, the time taken to walk 5 m and return was 3.3 (SD 5.0)s longer than the time to walk 10 m straight, but there was a large variation with some patients walking faster. The measured time to turn in a second group of 27 patients was 3.2 (SD 1.6)s. The times taken to walk 10 m straight and 5 m and return, and the time taken to turn were all highly correlated (r = 0.69 or more). CONCLUSIONS: Timing walking over 5 m with a return is an acceptable alternative to the 10 m straight walk, but the actual time taken varies. On average, the walk with a turn is 3.2 s longer but in individual patients the difference may be much more or less. Sometimes the walk with a turn is even faster than that without.

Physical fitness related to age and physical activity in older persons.

OBJECTIVE: This study investigated physical fitness as a function of age and leisure time physical activity (LTPA) in a community-based sample of 624 persons aged 57 yr and older. METHODS: LTPA during the last 12 months was assessed through personal interviews. A wide range of physical fitness components was measured using performance-based tests. RESULTS: Physical fitness was associated with the interaction age by LTPA in only a few components, in a gender-specific way, with generally larger differences in fitness between active and less active persons with increasing age. All LTPA, including low intensity LTPA, is positively and age-independent associated with most physical fitness components. CONCLUSION: The importance of LTPA typically participated in by the general population lies not so much in the delaying of the motor aging process but rather in a general, age-independent, positive effect.

Effect of casein-based semi-synthetic food on renal acid excretion and acid-base state of blood in dogs.

Urinary acid excretion and blood acid-base state were determined in dogs fed a casein-based semi-synthetic food (SSF), to which different amounts of salts had been added, in comparison with feeding normal dog food. Net acid excretion (NAE) and inorganic acid excretion (IAE) increased during SSF feeding. IAE was higher than the acid load calculated from the sulphur and phosphorus content of the casein. This higher IAE appeared to be due to the presence of calcium and magnesium phosphate in the diet, because calcium and magnesium may be in part precipitated as carbonate, leaving phosphate to be absorbed as phosphoric acid. Acid excretion decreased by addition of CaO. When no neutral Na+ and K+ salts were added, the increase in NAE was accompanied by a metabolic acidosis. K+ was more effective in attenuating the acidosis than Na+. On the basis of these findings a diet can be made which imposes a known acid load, and provides stable baseline values. Hence, any additions that influence the acid-base balance can be properly studied. The data obtained in these and future studies utilising this diet may be of help in optimising the composition of nutrient solutions to be used in the care of critically ill patients.

The relationship between comfortable and most metabolically efficient walking speed in persons with unilateral above-knee amputation.

Walking is most efficient when the least energy is spent over a certain distance. In six normal male subjects and 11 males with above-knee amputation the comfortable self-selected walking speeds and the most metabolically efficient walking speeds were determined. For that purpose energy expenditure was measured per second and per meter at six incremental walking speeds. Heart and step rate were registrated also at each walking speed. The results showed that in subjects who have not undergone amputation the comfortable walking speed is the same as the most efficient walking speed. However, in the above-knee amputee group, the comfortable walking speed is lower than the most efficient walking speed. When both groups walked at their own efficient walking speed they had the same energy expenditure per second.

Pitfalls in acid/base experiments with conscious dogs.

Arterial pH and blood gases were measured at intervals in conscious dogs after their first human contact of the day. Blood was sampled through an indwelling catheter in the aorta without disturbing the animals. It appeared that in the first 90 min arterial PO2, oxygen saturation and haemoglobin concentration significantly declined. PCO2 and pH changed less consistently when the acid/base status of the dogs was normal, but when a non-respiratory acidosis was present there was a significant decrease in pH and a significant increase in PCO2. Arterial pH and blood gases were also measured before and after feeding the animals. It appeared that an appreciable metabolic alkalosis developed within 2 h after a meal. The "alkaline tide" was accompanied by a trend to higher values for PCO2. It is concluded that, after a period of seclusion, renewed human contact causes behavioural changes in a dog, which may result in appreciable transitory changes in arterial pH and blood gas values. Blood sampling from conscious dogs should therefore take place after a proper period of habituation; preferably, a few samples should be taken at intervals to check that a steady state has been reached. If possible, blood should be collected before feeding; in any case the relationship in time of blood sampling to feeding should be constant throughout.

Influence of changes in cardiac output on the acid-base status of arterial and mixed venous blood.

While maintaining the arterial CO2 tension constant near the normal level of the dog (4.3 kPa), we studied the influence of decreasing cardiac output on both the arterial and mixed-venous blood acid-base status in anaesthetized, artificially ventilated dogs. Cardiac output was manipulated by applying positive end-expiratory pressure (PEEP), and by beta-adrenergic blockade to suppress a compensatory heart rate response. The systemic vascular response was attenuated by alpha-adrenergic blockade. Metabolic rate remained virtually unchanged when cardiac output decreased. Under these conditions a fall in cardiac output led to a shift of the arterial acid-base status in the direction of a metabolic acidosis. The changes occurring in the mixed-venous blood resembled those of an in-vivo CO2 bufferline, with the shift being such as if a respiratory acidosis was developing.

Inhibition of carbonic anhydrase in dog plasma.

Using a pH stat method, we measured the activity of carbonic anhydrase (CA) from dog erythrocytes in the presence of various amounts of dog plasma. A plasma factor appeared to be able to inhibit about 86% of the total CA activity, corresponding to the relative activity of CA II. Naiodoacetate was shown to inhibit the total CA activity up to about 13%, corresponding to the relative activity of CA I. C1- inhibited the total CA activity up to about 20%, presumably mainly through its strong influence on Ca I. It is concluded that with a degree of haemolysis of up to 3%, no appreciable plasma CA activity will occur.

Permeability of the human placenta to bicarbonate: in-vitro perfusion studies.

The effect of maternal acidosis on fetal acid-base balance was studied in a dual circuit perfusion of a single cotyledon in normal, term, human placentas. Both the fetal and maternal (intervillous) circulations were perfused with a Krebs-Ringer solution adjusted to pH values between 7.35 and 7.45. After a control period, the perfusate in the maternal circulation was replaced by an acidified medium (mean pH 7.06) for 30 min. This was followed by a second control period of 30 min during which the acidified maternal perfusate was replaced with the original medium. During the 30 min of maternal acidosis, fetal vein pH was not significantly altered despite the large decrease in maternal artery pH, but there was an efflux of total CO2 (tCO2) from the placenta into the maternal circulation which was not matched by an influx of tCO2 from the fetal circulation. The tCO2 transferred was in the form of bicarbonate rather than dissolved CO2, but the maximal rate of tCO2 transfer of in the form of bicarbonate was lower than the rate of placental transfer of tCO2 necessary in vivo. It is probable therefore that bicarbonate does not play a major role in placental CO2 transfer but the placental tissue bicarbonate pool may play an important part in buffering the fetus against changes in maternal pH or blood gas status.

On the reliability of the Henderson-Hasselbalch equation in routine clinical acid-base chemistry.

This paper deals with the variability of the practical coefficient of the first ionisation equilibrium of carbonic acid as related to the CO2 in the liquid phase (Henderson-Hasselbalch equation) (Formula: see text) and that of the practical coefficient of the first ionisation equilibrium of carbonic acid as related to the CO2 in the gas phase (modified Henderson-Hasselbalch equation) (Formula: see text).