While the appearance of oscillation can be perceived immediately, the stress resulting from it depends not only on the intensity of the oscillation, but also on the duration of exposure. The figure shows the evaluated vibration intensities of equal intensities (effective value of vertical accelerations) as a function of the duration of exposure based on the criteria 'well-being', 'performance' and 'health'.
As a consequence, durations of exposure between 1 and 10 minutes lead to the same stress. If the exposure continues for a longer time, the stress remains the same, if the square of the evaluated vibration intensity K decreases with respect to the exposure time t (Figure in slide 18 with double logarithmic scale)
A K-value of 20 is considered as a limiting value, which impairs the well-being of humans even when the exposure is limited to short durations. When exposed to the same stress for more than 1.5 hours, impairments of performance increase, and a daily duration of exposure of more than 4 hours can lead to a negative impact on health.