The ballistocardiogram in overweight young adults

The ability to record the mechanical function of the heart is the principal value of the ballistocardiogram. In young healthy individuals the ballistocardiogram is consistently normal. Since overweight is apparently an important factor in the development of degenerative heart diseases, a study was undertaken to correlate excess weight in otherwise healthy young students with their respective ballistocardiograms, obtained on a direct-body ballistocardiograph.

Effects of exposure of obese rats to simulated high altitudes

Osborne-Mendel rats became obese when fed a high fat diet for 6–15 months. Obese rats and stock-fed rats were exposed 6 1/2 hours a day, 5 days a week to 18,000 or 25,000 feet simulated altitude for from 4 to 6 months. Both groups of rats developed the same degree of polycythemia and had the same mortality rate. The obese rats lost more weight from altitude exposure and also showed a slightly higher incidence of cardiovalvular thickening and cardiac vegetations, particularly among those that died. The mean heart weight of unexposed obese rats was 50% greater than that of stock-fed rats; the heart weights of both groups increased about 70% following 191 days of exposure. In acute altitude tests at 33,500 feet simulated altitude, both Osborne-Mendel and Sprague-Dawley rats on the high-fat diet, irrespective of the degree of obesity, died within 86 minutes. Sixty per cent of the stock-fed rats survived for a longer period. Some of the heaviest Osborne-Mendel rats on the high-fat diet died within 3 minutes at this altitude. Preoxygenation prevented these early deaths, but neither preoxygenation nor a slow rate of ascent (500 ft/min) had any effect on the high mortality of rats on a high-fat diet exposed to altitude.