Having analyzed the data from literature, the authors suggested a single-number index for integral assessment of combined vibratory and force load during work with vibrating manually held device. The index considers the acceleration value and combination of grip and feed forces. The authors calculated average values of these forces and the resultant coupling force for various device weights. If the coupling force is considered, the risk of vibration disease varies in accordance with forecast model and demonstrates 1.06-1.1 up to 1.6-2.6 times increase depending on device weight. The index could be useful for hygienic certification of manually held devices.