Research on cardiology published by R.V. Maikala et al.

"The effects of varied seating posture conditions on cardiovascular responses in healthy women were studied during exposure to whole-body vibration (WBV). After an assessment of upper-body fitness, 14 healthy young women were exposed to 3, 4.5, and 6 Hz (at 0.9g(r.m.s.) in the vertical direction) on a vibration simulator for 3 separate days," scientists in the United States report (see also Cardiology).

"Each day the protocol consisted of 6 min of baseline without WBV (control), 8 min of WBV exposure to a single frequency either 'with' or 'without' backrest, 4 min of recovery, followed by 8 min of WBV at the same frequency with opposite backrest condition, and 4 min of recovery. Cardiac output was estimated by using the carbon dioxide rebreathing technique during three conditions: (1) control; and before completion of WBV session of sitting (2) 'with'; and (3) 'without' backrest during exposure to WBV. Statistical analysis revealed that pulmonary oxygen uptake responses were not influenced by the change in frequency but only by the posture. Although cardiac output reached equal levels during sitting 'without' backrest at 3 and 4.5 Hz (P > 0.05), the heart rate difference was significant between these frequencies (P 0.05), the greater increase in cardiac output (P

The researchers concluded: "Results from the present study are anticipated to further contribute to the understanding of the adverse health effects on human performance due to WBV."

Maikala and colleagues published their study in International Journal of Industrial Ergonomics (Cardiovascular ...