ABSTRACT
OBJECTIVE: To investigate the effect of physical training (PTr) on upper leg muscle area, muscle strength and muscle endurance expressed as upper leg muscle function (ULMF) in relation to exercise performance in CHF. DESIGN: Randomised to a training (TG) or control group (CG). SETTING: Outpatient cardiac rehabilitation centre of community hospital. PATIENTS: 77 CHF patients (59 men and 18 women), NYHA class II/III, age 59.8+/-9.3 years, LVEF 27+/-8%. Sixteen patients dropped out during the intervention period, 61 patients (M/F:46/15) completed the study. INTERVENTION: PTr (combined strength and endurance exercises) four times per week, twice supervised and twice at home, during 26 weeks. MAIN OUTCOME MEASURES: LVEF, body composition, daily physical activity, exercise performance, upper leg muscle area and isokinetic leg muscle variables. RESULTS: Workload and peak oxygen consumption decreased in the CG (-4.1% and -4%) but increased in the TG (+5% and +4%) following PTr (p<0.05, ANOVA repeated measures). Hamstrings area decreased in the CG and did not change in the TG (p<0.05, ANOVA repeated measures). ULMF improved in the TG, but remained unchanged in the CG (+13.0% and 0.0, respectively, p<0.05; ANOVA repeated measures). At baseline and after intervention nearly 60% of the variance in maximal workload was explained by ULMF and quadriceps muscle area (multiple regression analysis). CONCLUSIONS: In CHF patients, home-based training in conjunction with a supervised strength and endurance training program is safe, feasible and effective and does not require complex training equipment. Physical training prevented loss of hamstrings muscle mass and improved exercise performance by enhancing muscle strength and endurance.
Subject(s)
Exercise Therapy , Exercise/physiology , Heart Failure/rehabilitation , Muscle, Skeletal/physiology , Female , Hand Strength , Humans , Isometric Contraction , Leg , Male , Middle Aged , Multivariate Analysis , Physical EnduranceABSTRACT
BACKGROUND: Chronic heart failure (CHF) is characterized by symptoms like fatigue, dyspnoea and limited exercise performance. It has been postulated that maximal exercise performance (Wmax) is predominantly limited by skeletal muscle function and less by heart function. AIM: To study the interrelation between most relevant muscle and anthropometrical variables and Wmax in CHF patients in order to develop a model that describes the impact of these variables for maximal exercise performance. DESIGN: In 77 patients with CHF Wmax was assessed by incremental cycle ergometry until exhaustion (20 Watt/3 min). Peak torque (strength) and total work (endurance) for the quadriceps and hamstrings were assessed by isokinetic dynamometry. Isometric strength was measured by hand dynamometry. Relevant muscle areas were calculated by computerized tomography scan. RESULTS: Significant correlations between Wmax and isokinetic muscle parameters (peak torque and total work) ranged from 0.41-0.65 (P<0.01). Other significant relationships (P<0.01) with Wmax were obtained for age (r=-0.22), gender (r=0.45), fat free mass (FFM) (r=0.51), quadriceps muscle area (r=0.73), hamstrings muscle area (r=0.50), upper leg muscle function (i.e., a combination of muscle strength and muscle endurance) (r=0.71) and isometric strength (r=0.63). Multiple regression analysis showed that upper leg muscle function and quadriceps muscle area could predict 57% of the variance in Wmax. CONCLUSION: Muscle strength and muscle endurance, combined with quadriceps muscle area are the main predictors of maximal exercise performance in patients with CHF.
Subject(s)
Exercise Tolerance/physiology , Heart Failure/physiopathology , Adipose Tissue/physiology , Aged , Anthropometry , Chronic Disease , Exercise Test , Female , Humans , Isometric Contraction/physiology , Leg/physiology , Male , Middle Aged , Multivariate Analysis , Muscle, Skeletal/physiology , Physical Endurance/physiology , Sex Factors , Statistics as Topic , Stroke Volume/physiologyABSTRACT
OBJECTIVE: To examine the effect of a sports drink during strenuous exercise on duodenal motility and gastrointestinal symptoms. METHODS: In a cross-over design, seven male triathletes performed two 170-min run-bike-run tests at about 70% peak oxygen uptake (O(2peak)), with either a 7% carbohydrate (CHO) sports drink or tap water. Antroduodenal motility (phase III of the migrating motor complex; MMC) was measured with an ambulant manometry system. The effect of the two exercise trials on the first appearance of the MMC was assessed in the postprandial period. RESULTS: Exercise heart rate, percentage O(2peak) and loss of body mass did not differ significantly between the two trials. After the start of the exercise, the expected time before the first phase III occurrence, based on the actual energy intake of the last meal in the morning before exercise (1048 +/- 294 kcal), a fixed gastric emptying rate and a lag phase for solid food, was 183 +/- 113 min (mean +/- standard deviation [SD]). The real time period between the start of the exercise with CHO and the first phase III was 63 +/- 61 min, which was significantly shorter than that observed with tap water (152 +/- 59 min). Both real time periods were shorter than the expected time period of 183 +/- 113 min (P < 0.05). During exercise, the number of subjects with a phase III was higher with CHO than with tap water (n =6 v. n =1; P < 0.05). Also, the median number of phases III per hour with CHO was higher than with tap water (0.4 v. 0.0; P < 0.05). During cycling, significantly more phases III per hour (0.9) were measured than during running (0.2). All subjects reported one or more gastrointestinal symptoms during exercise, however, without a clear association with the mode of exercise or supplementation. CONCLUSIONS: Prolonged exercise results in gastrointestinal symptoms and a significant interruption of postprandial motility. Only the latter phenomenon depends on the mode of exercise and supplementation.
