Biomedical subjects

Prithwish Banerjee

Publications and source records attributed to Prithwish Banerjee.

5 recordsLinked to original sources

PubMed2005

Prolonged electrical muscle stimulation exercise improves strength and aerobic capacity in healthy sedentary adults.

This investigation evaluated training responses to prolonged electrical muscle stimulation (EMS) in sedentary adults. Fifteen healthy subjects (10 men, 5 women) with a sedentary lifestyle completed a 6-wk training program during which they completed an average of 29 1-h EMS sessions. The form of EMS used by the subjects was capable of eliciting a cardiovascular exercise response without loading the limbs or joints. It achieved this by means of inducing rapid, rhythmical contractions in the large leg muscles. A crossover study design was employed with subjects undergoing their habitual activity levels during the nontraining phase of the study. The training effect was evaluated by means of a treadmill test to determine peak aerobic capacity [peak oxygen consumption (Vo(2))], a 6-min walking distance test, and measurement of body mass index (BMI) and quadriceps muscle strength. At baseline, the mean values for peak Vo(2), 6-min walking distance, quadriceps strength, and BMI were 2.46 +/- 0.57 l/min, 493.3 +/- 36.8 m, 360.8 +/- 108.7 N, and 26.9 +/- 3.4 kg/m(2), respectively. After training, subjects demonstrated statistically significant improvements in all variables except BMI. Peak Vo(2) increased by an average of 0.24 +/- 0.16 l/min (P < 0.05), walking distance increased by 36.6 +/- 19.7 m (P < 0.005), and quadriceps strength increased by 87.5 +/- 55.9 N (P < 0.005); we did not observe a significant effect due to training on BMI (P > 0.05). These results suggest that EMS can be used in sedentary adults to improve physical fitness. It may provide a viable alternative to more conventional forms of exercise in this population.

Adaptation, Physiological↗

PubMed2005

Electrical stimulation of unloaded muscles causes cardiovascular exercise by increasing oxygen demand.

BACKGROUND: The development of new strategies to encourage increased levels of physical activity can help to reduce the incidence of cardiovascular disease. A new system of electrical muscle stimulation (EMS) has been developed that attempts to cause an increase in energy expenditure by mimicking the action of shivering in the body. The purpose of this study was to show that this form of EMS is capable of eliciting a cardiovascular exercise response in healthy adults. DESIGN: An observational study. METHODS: Ten healthy volunteers completed a maximal treadmill test and four EMS sessions using a hand-held EMS device that delivered current to the body via five silicone rubber electrodes on each leg. At each session subjects completed 3 min stimulation at each of four stimulation outputs (10, 20, 30 and 40% of maximum output) while cardiopulmonary gas exchange and heart rate (HR) were measured. Physiological responses at increasing levels of stimulation were evaluated. RESULTS: Average (+/-SD) HR and oxygen consumption (VO2) levels of 67+/-11 bpm and 4.7+/-1.2 ml/kg per min at rest, respectively, were increased to 186+/-10 bpm and 44.9+/-9.8 ml/kg per min at peak exercise intensity on treadmill testing. The electrical stimulation was generally well tolerated by the subjects. Subjects demonstrated statistically significant increases in all physiological variables measured with successive increases in stimulation intensity. Peak HR and VO2 at 40% stimulation intensity were 101+/-12 bpm and 14.9+/-4.3 ml/kg per min, respectively. CONCLUSIONS: These results demonstrate that this form of EMS is capable of producing a physiological response consistent with cardiovascular exercise at mild to moderate intensities. It achieves this without producing gross movement of the limbs or loading of the joints. This EMS-induced cardiovascular exercise response could be used to promote increased levels of physical activity in populations unable to participate in voluntary exercise.

Adaptation, Physiological↗

PubMed2004

Diastolic heart failure. Paroxysmal or chronic?

Heart failure with preserved systolic function is considered by some to be synonymous with diastolic heart failure (DHF). Although recent epidemiological studies have suggested that DHF constitutes 30-50% of all patients with heart failure, many cardiologists dealing with ambulant heart failure patients on a daily basis find that the vast majority of heart failure patients have systolic dysfunction. What could be the reasons for this? Referral bias and varying diagnostic thresholds and interpretation of results could be one important reason. Heart failure with preserved systolic function comprises a heterogeneous group of conditions: whilst some patients may truly have DHF, others may have heart failure due to subtle systolic dysfunction (noted on tissue Doppler imaging of the left ventricular long axis). Other patients actually have pulmonary disease, obesity or ischaemic heart disease, and have their symptoms attributed to 'diastolic heart failure' on the basis of 'abnormal' mitral diastolic flow indices that may, in fact, simply reflect aging. True DHF may be much less prevalent than suggested. A further possibility is that heart failure in patients with diastolic dysfunction might be paroxysmal rather than chronic. This group of patients may present predominantly to acute units like accident and emergency, coronary care units and intensive care units and are, therefore unlikely to figure prominently in the usual outpatient population of chronic systolic left ventricular dysfunction.

Acute Disease↗

PubMed2002

Diastolic heart failure: neglected or misdiagnosed?

Recent epidemiological studies suggest that 30% to 50% of patients with heart failure (HF) have preserved left ventricular (LV) systolic function. These patients, often presumed to have diastolic heart failure (DHF), appear to have lower short-term but similar long-term mortality when compared to patients with HF and LV systolic dysfunction. Rates of recurrent hospitalization and costs of care appear similar in the two groups of patients. Therefore, DHF may contribute significantly to the burden of disease caused by HF. Exertional breathlessness, the principal symptom of HF, has many causes, including obesity, pulmonary disease and myocardial ischemia. A diagnosis of DHF by exclusion, based on symptoms in the absence of important LV systolic dysfunction or major valve disease, is unsatisfactory. Unfortunately, as yet, no reliable definition with which to make a positive diagnosis of DHF has been agreed on, frequently rendering this diagnosis uncertain. Echocardiography has several limitations, whereas hemodynamic confirmation of DHF by cardiac catheterization is potentially complex and not practically feasible for many patients. Treatment of DHF remains empirical and unsatisfactory because of the lack of large-scale randomized controlled trials in this area. Currently, three large outcome studies on DHF are in progress along with other smaller trials. These should start to provide some of the answers we need to diagnose and effectively treat DHF.

Diastole↗

PubMedDate not supplied

Diastolic heart failure: a difficult problem in the elderly.

Heart failure with normal systolic function has been equated to diastolic heart failure (DHF). DHF appears to be quite common in the elderly, especially in elderly women with hypertension. Recent epidemiologic studies suggest that 30%-50% of patients with heart failure may have DHF. Morbidity for DHF is considerable and comparable to that of heart failure with left ventricular systolic dysfunction. Both groups of patients have similar rates of recurrent hospitalization and cost of care. Long-term mortality also appears to be similar in the two groups of patients. With the aging of the population, the numbers of patients with DHF will continue to rise and are likely to contribute significantly to the burden of disease caused by heart failure. Unfortunately, as yet, no reliable definition has been found for DHF. Currently the diagnosis of DHF is often made by exclusion, and treatment is empirical and unsatisfactory because of the lack of large-scale, randomized, controlled trials in this area; however, several large and other smaller trials are currently in progress that will hopefully provide some answers.

Aged↗