Katharina Meyer

Interval training in patients with severe chronic heart failure : analysis and recommendations for exercise procedures

This study analyzes a new exercise training procedure, which includes interval exercise training on cycle ergometer (IntCT) (30-s work phases/60-s recovery phases) and on treadmill (60-s work and recovery phases each). Training was applied for 3 wk in 18 patients with severe chronic heart failure (CHF) ((mean +/- SEM) age 52 +/- 2 yr, ejection fraction 21 +/- 1%). Peak VO2 was increased from 12.2 +/- 0.7 to 14.6 +/- 0.7 ml-kg-1 min-1 owing to training (P < 0.001). A specific steep ramp test (work rate increments 25 W.10 s-1) was developed to derive exercise intensity for work phases in IntCT, which was 50% of the maximum work rate achieved. Steep ramp test was performed at the start of the study to determine the initial training work rate, then weekly to readjust it. Since the maximum work rate achieved from this test increased weekly (144 +/- 10 W -->172 +/- 10 W-->200 +/- 11 W; P < 0.001), the training work rate also increased (72 +/- 4 W-->86 +/- 6 W-->100 +/- 7 W; P < 0.001). Physical responses to IntCT were measured. There was no significant change in heart rate, blood pressure, and ratings of perceived exertion (RPE) using a Borg Scale between the first and the third week of training (heart rate 88 +/- 3 b.min-1; blood pressure 115 +/- 4/80 +/- 2 mm Hg; leg fatigue 12 +/- 1; dyspnea 10 +/- 1). Mean lactate concentration (1.70 +/- 0.09 mmol-1-1) indicated an overall aerobic range of training intensity. When compared with the commonly used intensity level of 75% peak VO2 from an ordinary ramp test (work rate increments 12.5 W.min-1), the performed training work rate was more than doubled (240%; P < 0.0001) while cardiac stress was lower (86%; P < 0.01). Values of norepinephrine and epinephrine as well as of RPE corresponded to those measured at 75% peak VO2. Interval exercise training is thus recommended for selected patients with CHF as it allows intense exercise stimuli on peripheral muscles with minimal cardiac strain. Using a steep ramp test, training work rate can be determined and readjusted weekly during initial training period.

Eccentric Exercise in Coronary Patients: Central Hemodynamic and Metabolic Responses

PURPOSE With lengthening (eccentric) muscle contractions, the magnitude of locomotor-muscle mass and strength increase has been demonstrated to be greater compared with shortening (concentric) muscle contractions. In healthy subjects, energy demand and heart rate responses with eccentric exercise are small relative to the amount of muscle force produced. Thus, eccentric exercise may be an attractive alternative to resistance exercise for patients with limited cardiovascular exercise tolerance. METHODS We tested the cardiovascular tolerance of eccentric exercise in 13 coronary patients (ages 40-66) with preserved and/or mild reduced left ventricular function. Patients were randomly assigned to either an eccentric (ECC; N = 7) or a concentric (CON; N = 6) training group and trained for 8 wk. Training workload was increased progressively (from week 1 to 5) to an intensity equivalent to 60% [OV0312]O(2peak). RESULTS On average, maximum power output achieved with ECC was fourfold compared with CON (357 +/- 96 W vs 97 +/- 21 W; P < 0.005), whereas measures of oxygen uptake and blood lactate were significantly lower (P < 0.05 each), and ratings of perceived exertion were similar for ECC and CON. During a 20-min session of ECC and CON, central hemodynamics was measured by means of right heart catheterization. During ECC, responses of mean arterial blood pressure, systemic vascular resistance, pulmonary capillary pressure, cardiac index, and stroke work of the left ventricle on average were in the normal range of values and similar to those observed during CON. Compared with baseline, after 8 wk of training, echocardiographic left ventricular function was unchanged. CONCLUSION The results indicate uncoupling of skeletal muscle load and cardiovascular stress during ECC. For low-risk patients with coronary heart disease without angina, inducible ischemia, or left ventricular dysfunction, ECC can be recommended as a safe new approach to perform high-load muscular exercise training with minimal cardiovascular stress.

Exercise training in heart failure: recommendations based on current research.

A review of methods used for exercise training in stable chronic heart failure patients (CHF) shows a lack of standardization to guide prescription. Previous recommendations have been adopted from fitness training or rehabilitation studies. A model for use in CHF patients requires specific guidelines which respect the various manifestations of this illness. Pathology and exercise tolerance of patients with CHF allow only a few selected activities to be performed, such as walking and cycle ergometer training. Although the steady state method has usually been applied for aerobic exercise, the interval method has been shown to cause greater exercise stimuli to peripheral muscle than that obtained during steady state training methods without inducing greater cardiovascular stress. There is no consensus at present as to an optimal parameter for measuring intensity. An intensity of 40-80% peak oxygen consumption (VO(2)) has been applied successfully. A heart rate reserve of 60-80% or 75% of peak heart rate was used as a guide to exercise intensity without consideration of the impaired force-frequency relationship in myocardial performance. Because intensity, duration, and frequency of exercise are closely interrelated, initial exercise should be kept at 40-50% peak VO(2) with exercise duration of > 3-5 min x session performed several times daily. Progression should be followed in this order: duration, then frequency, then intensity. Resistance training can be recommended when small muscle groups are involved, using short bouts of work phases and small numbers of repetitions. To increase respiratory muscle strength and endurance, resistive inspiratory muscle training at intensity 25--35% maximum inspiratory pressure, and performed 20-30 min x d(-1), is recommended. On the basis of currently available research, supervised inpatient training programs should be preferred. Future research should be performed with respect on statistically sufficient, randomized, and controlled long-term studies that compare different training modes, intensities, frequency/duration ratios, and rates of progression.

Short-term reproducibility of cardiopulmonary measurements during exercise testing in patients with severe chronic heart failure ☆ ☆☆ ★

Eleven men with severe chronic heart failure (peak cardiac index 4.0 +/- 0.2 L/m2/min), six on a heart transplantation waiting list, were prospectively assessed. To determine reproducibility of cardiopulmonary and hemodynamic variables for clinical purposes during ramp bicycle ergometry, the patients underwent two ramp bicycle ergometer tests (3 minutes unloaded, work rate increments of 12.5 W/min) with a 1-week interval between tests. Oxygen uptake (VO2) carbon dioxide production (VCO2), and ventilation were measured breath by breath, and calculations were performed to determine gas exchange ratio, oxygen pulse, ventilatory equivalents of oxygen and carbon dioxide, and end-tidal partial pressure for oxygen and carbon dioxide. Additionally, heart rate, blood pressure, and lactate levels were assessed. Measurements were performed at submaximum work rate levels of 25 W, 50 W, and 75 W at ventilatory threshold and at peak work rate. At all measurement points, the coefficient of variation for cardiopulmonary variables was between 1.4% and 7.1% for submaximum work rate levels, between 1.2% and 4.4% at ventilatory threshold, and between 2.4% and 7.1% at peak work rate. For heart rate, blood pressure, and lactate levels, coefficient of variation was between 2.7% and 5.7% for submaximum work rate levels, between 1.4% and 6.1% at ventilatory threshold, and between 1.2% and 5.5% at peak work rate. The data suggest high reproducibility for duplicate measurements of cardiopulmonary and hemodynamic variables during ramp bicycle ergometry in patients with severe chronic heart failure. The results may be used to determine whether any variable in a single patient is significantly different from that obtained in a previous exercise test or if the change is within experimental error.

Delayed VO2 kinetics during ramp exercise: a criterion for cardiopulmonary exercise capacity in chronic heart failure.

PURPOSE Kinetics of VO2 at onset of constant work rate exercise was previously shown to be slowed in patients with chronic heart failure (CHF) compared with that in healthy normals. Because bicycle ergometry with ramp protocol is usually used for exercise testing with CHF patients, it would be of practical importance if it can be shown that a delay in the time interval of linear increase of VO2 (TILIV) to work rate occurs after beginning ramp exercise. Data of central hemodynamics (CHF) and noninvasive cardiopulmonary parameters (CHF, normals) should also correlate with VO2 delay time if this parameter is related to cardiopulmonary exercise capacity. METHODS Fifteen males with CHF (mean +/- SEM: age 52 +/- 2 yr; ejection fraction 32 +/- 4%; peak cardiac index 3.9 +/- 0.3 L x m(-2) x min(-1)) and 28 healthy males (50 +/- 1 yr) were assessed. During ramp bicycle ergometry (3 min unloaded, work rate increments of 12.5 W x min(-1)), VO2 was measured breath by breath. RESULTS After the onset of ramp exercise, there was a difference in the TILIV between patients and normals (83.7 +/- 3.6 vs 66.8 +/- 2.9 s; P < 0.001). Significant differences between both groups were also found for VO2 at ventilatory threshold (VT) (10.1 +/- 0.1 vs 15.2 +/- 0.7 mL x kg(-1) x min(-1); P < 0.0001), VO2 at VT relative to predicted VT (58 +/- 4 vs 97 +/- 4%; P < 0.0001), peak VO2 (13.2 +/- 1.0 vs 34 +/- 1.4 mL x kg(-1) x min(-1), P < 0.001), and increase of systolic blood pressure (36 +/- 7 vs 71 +/- 5 mm Hg; P < 0.0001). In CHF, the TILIV correlated significantly with peak cardiac index and VO2 at VT (r = -0.71; P < 0.005 each), relative value of VO2/kg at VT (r = -0.61; P < 0.03), peak VO2/kg (r = -0.63; P < 0.01), and increase of systolic blood pressure (r = -0.52; P < 0.02). In the normals only VO2/kg at VT correlated significantly with TILIV (r = -0.41; P < 0.03). In patients, stepwise regression analysis identified three predictors which could explain 79% of the variance of TILIV: VO2/kg at VT (r2 = 0.51), peak cardiac index (r2 = 0.20), and peak VO2/kg (r2 = 0.08). CONCLUSION TILIV, determined at the onset of ramp exercise, is prolonged in CHF patients compared with that in normals and reflects severity of functional impairment because of reduced cardiac index and aerobic capacity. TILIV can provide information about changes in cardiopulmonary exercise capacity and thus can be used for follow-up and treatment studies in CHF.

Verbesserung der aeroben Kapazität bei chronischer Herzinsuffizienz : Welche Trainingsmethode ist geeignet ?

Bislang existieren keine standardisierten Richtlinien zur Methodik eines körperlichen Trainings für Patienten mit schwerer chronischer Herzinsuffizienz. Patienten, die in der Vergangenheit in Trainingsstudien involviert wurden, zeigen eine große Variabilität der kardialen und funktionellen Einschränkungen, bei mittleren Werten der Ejektionsfraktion zwischen 18 und 35% und der peak VO2 zwischen 12,2 und 25,4 ml/kg/min. Zur Bestimmung der Trainingsbelastung wurde eine VO2 zwischen 40 und 70% der peak VO2 und/oder eine Herzfrequenz zwischen 60 und 80% der maximalen Herzfrequenz gewählt. Ferner variierten die Häufigkeit (zwischen 3- und 7x pro Woche) und die Dauer des Trainings (zwischen 20 und 60 min/Trainingseinheit) stark. Das Ausdauertraining wurde ausschließlich in der kontinuierlichen Dauermethode angewandt. Wir entwickelten eine neue Intervall-Trainingsmethode, die intensive Belastungsreize auf die periphere Muskulatur erlaubt, die kardiale Belastung jedoch gering hält. Nach nur 3 Wochen dieses Intervalltrainings zeigte sich die Verbesserung der aeroben Kapazität in einer Größenordnung, wie sie erst nach längeren Trainingsphasen bei Anwendung der Dauertrainingsmethode berichtet wurde. Zur Bestimmung der Belastung für die Belastungsphasen des Intervalltrainings wurde ein spezifischer steiler Rampentest entwickelt. Eine Analyse der akuten körperlichen Reaktionen während des steilen Rampentests und während des Intervalltrainings ergab, daß beide Belastungsformen selbst für solche Patienten tolerabel waren, die eine Ejektionsfraktion von nur 13%, einen maximalen Herzindex von nicht mehr als 1,6 l/m2/min oder eine peak VO2 von lediglich 8,5 ml/kg/min aufwiesen. Standardized guidelines for exercise training for patients with chronic congestive heart failure (CHF) have not been established. In the past CHF patients involved in exercise training studies demonstrated a wide range of cardiac and functional impairment, with an ejection fraction between 18 and 35% and a peak VO2 between 12.2 and 25.4 ml/kg/min on average. For determination of training intensity, a VO2 between 40 and 70% of peak VO2 and/or training heart rate between 60 and 80% of peak heart rate was used. There was also a wide range for frequency (between 3 and 7 times per week) and duration of training (between 20 and 60 min per session). For aerobic exercise training only continuous training methods were applied. We have developed a new interval training method which allows intense exercise stimuli on peripheral muscles with minimal cardiac strain. After only three weeks of training, the improvement in aerobic capacity was similar to that reported after longer training periods using continuous methods. To determine work rate for work phases of interval training, a special steep ramp test was developed. By analysis of acute physical responses to this testing procedure and to the interval training, both were proven to be tolerable in CHF patients, even if their ejection fraction is as low as 13%, or peak cardiac index not greater than 1.6 l/m2/min, and peak VO2 less than 8.5 ml/kg/min.

Left ventricular function during interval and steady state exercise.

PURPOSE Interval training (INT) is a commonly used method of exercise training in both athletic and clinical populations. Although we generally understand left ventricular (LV) function during steady state (SS) exercise, there are no data regarding LV function during INT. METHODS We studied eight healthy, physically active volunteers during upright cycle ergometry during 15 min of both SS and INT, at the same average power output (90% individual anaerobic threshold), using first pass radionuclide ventriculography. During INT (60s/60s), measures of LV function were made during work (220 W) after 4 and 12 min and during recovery (120 W) after 7 and 15 min. These were compared with the average of four temporally matched measures made during SS (170 W). RESULTS During INT, LV ejection fraction increased from rest (67 +/- 6%) to 77 +/- 5, 80 +/- 5, 77 +/- 5 and 79 +/- 4% after 4, 7, 12, and 15 min, respectively. During SS, LV ejection fraction was not significantly different at rest (70 +/- 4%) or during exercise (76 +/- 4, 79 +/- 4, 80 +/- 3, and 81 +/- 3%) after 4, 7, 12, and 15 min, respectively. Other measures of LV function (HR, BP, LV volumes, cardiac output, systemic vascular resistance, peak emptying, and filling rates) were likewise similar during temporally matched measurements during INT and SS. CONCLUSIONS Although there were the expected transitions of ejection fraction with work and recovery, the overall hemodynamic picture during INT was very similar to SS. These data suggest that LV function during INT is not substantially different to that during SS.

Prevention of obesity and physical inactivity–a socio-cultural challenge

Over the past 10 years, the prevalence of obesity has markedly increased in European countries (WHO 2004). In parallel, sedentary lifestyles and insufficient physical activity are common in about two-thirds of adult populations (WHO 2002). As obesity is the result of an imbalance between energy intake and energy expenditure, both eating and exercise patterns must be taken into account. The question is: How can we treat the obesity epidemic and begin to reduce the prevalence of obesity and physical inactivity within the populations concerned? What we do know is that simply providing advice about health-relevant behaviour does not necessarily mean that it will be followed. The complex nature of obesity and sedentary lifestyles makes it difficult to identify the multiple underlying causes of unhealthy behaviour, and this might be the reason why expensive population-based interventions have not been too successful to date. Both obesity and sedentary lifestyles are a consequence of socio-cultural systems that have developed over the past century, particularly since World War II. Never before have people of the Western world had such unrestricted access to large quantities of food, and fat and sugar have been the cheapest sources of calories. There are two sides to this coin: On the one hand, almost everyone, even people in low income brackets, has an adequate daily supply of energy; on the other hand, the social inequalities in diet are becoming increasingly obvious. Grocery stores that sell at low-price levels are less likely to offer low-fat foods and tend to stock a smaller range of higher quality fresh fruit and vegetables than those shops that sell at higher price levels. This implies that the impact of socio-economic factors on obesity may be mediated in part by the low cost of energy-rich foods. Moreover, industry’s marketing incentives promote obesity amongst the poorer sectors of society using concepts such as “buy one, get one free”. The larger the portions, the cheaper the relative price of the product. Nowadays, employees spend long hours sitting at their desks and working overtime instead of going home on time, being physically active and aiming for a better work–life balance. Moreover, people can move more quickly and easily from place to place–without having to expend any or very much energy to do so–than ever before. By 2015, the number of cars on the road is expected to grow by 10%– using Germany and Switzerland as an example–and the intensity of traffic is predicted to increase by up to 24%. Car manufacturers are exploiting these developments and marketing a new concept of “in-car living”. The car will become an interim space for working and eating. In the USA, nowadays 10% of all meals are eaten in the car and the trend is growing. Physical inactivity throughout the whole day is becoming increasingly prevalent, and physical activity as a necessity for health is becoming obsolete. Obesity and a sedentary lifestyle have a societal and an environmental rationale. As a consequence, both aspects must be addressed when looking for solutions. There are positive examples of solutions in other areas, such as using safety belts when driving, wearing helmets when riding bicycles and creating non-smoking public spaces. An important step towards the modification of social norms and the resulting changes in behaviour is to raise awareness among individuals and population groups. New, effective political J Public Health (2008) 16:1–2 DOI 10.1007/s10389-007-0155-8

Influence of different exercise protocols on functional capacity and symptoms in patients with chronic heart failure

This study compares hemodynamic, metabolic, and gas exchange responses, catecholamine levels, and symptoms in 35 male patients with chronic heart failure (CHF) ([mean +/- SD] age 53 +/- 11 yr; ejection fraction 24 +/- 11%) during three differently graded exercise test protocols. On three consecutive days patients performed cycle ergometry supine, with prolonged steps (prol BE) and right heart catheterization, ramplike cycle ergometry sitting (ramp BE), and ramplike treadmill walking (TMW). As in routine clinical practice, the prol BE was terminated when pathologic central hemodynamics and/or increased symptomology occurred, and ramp BE and TMW due to increased symptomology and/or physicians decision. During prol BE at ventilatory threshold (VT) the VO2 (8.6 +/- 1.8 ml.kg-1.min-1) was lower than during ramp BE (9.3 +/- 2.1 ml.kg-1.min-1) (P < 0.017) and TMW (11.8 +/- 2.3 ml.kg-1.min-1) (P < 0.0001). Prol BE, ramp BE, and TMW also differed significantly with respect to ventilation (22 +/- 7 l.min-1; 26 +/- 6 l/min-1; 29 +/- 7 l.min-1; P < 0.01) and heart rate (100 +/- 15 beats.min-1; 103 +/- 18 beats.min-1; 110 +/- 16 beats.min-1; P < 0.017). No differences were found in lactate levels, catecholamine levels, and ratings of leg fatigue and dyspnea. At test termination, the peak VO2 during prol BE (100.8 +/- 3.3 ml.kg-1.min-1) was lower than during ramp BE (13.3 +/- 4.1 ml.kg-1.min-1) (P < 0.0001) and TMW (14.7 +/- 3.4 ml.kg-1.min-1) (P < 0.0001). Peak norepinephrine value during ramp BE (4.531 +/- 2.788 nmol.l-1) was higher than during prol BE (3.707 +/- 2.262 nmol.l-1) (P < 0.001). Among the three tests, no significant differences were found for peak values of heart rate, lactate, and ratings of dyspnea. Although the VO2.kg-1 at VT was significantly higher during ramp BE and TMW compared to prol BE (P < 0.001), the values expressed as a percent of peak VO2.kg-1 were significantly lower (70 +/- 4%; 72 +/- 6%; 79 +/- 3%; P < 0.017). A systematic effect on aerobic capacity with reduced peak values during ramp BE and TMW was demonstrated when test termination was based primarily on pathological findings of central hemodynamics from prol BE.

Gesundheit in der Schweiz—Nationaler Gesundheitsbericht 2008

katharina.meyer@bfs.admin.ch In der Gesundheitsdiskussion der letzten Jahre ist man haufig davon ausgegangen, dass viele der neuen chronischen Erkrankungen in erster Linie durch individuelles Verhalten ausgelost werden, ganz nach der Vorstellung: Wer schlecht isst oder sich zu wenig bewegt, wird krank und ist letztlich selbst dafur verantwortlich. Die Forschung zeigt jedoch immer deutlicher, dass der Gesundheitszustand des Einzelnen auch von ausseren Einflussen bestimmt wird. Dazu zahlen soziookonomische Faktoren wie Bildung, Beruf und Einkommen bzw. soziokulturelle Determinanten wie ethnische Herkunft oder gesellschaftlicher Status. Wie gesund eine Gesellschaft ist, hangt also sowohl von individuellen als auch von gesellschaftlichen Bedingungen ab.