Vibration - Health Effects

Vibration-induced health conditions progress slowly. In the beginning, it usually starts as a pain. As the vibration exposure continues, the pain may develop into an injury or disease. Pain is the first health condition that is noticed and should be addressed in order to stop the injury.

Vibration-induced white finger is the most common condition among the operators of hand-held vibrating tools. The symptoms of vibration-induced white finger are aggravated when the hands are exposed to cold.

Vibration can cause changes in tendons, muscles, bones and joints, and can affect the nervous system. Collectively, these effects are known as hand-arm vibration syndrome. Workers affected by hand-arm vibration syndrome commonly report:

• attacks of whitening (blanching) of one or more fingers when exposed to cold
• tingling and loss of sensation in the fingers
• loss of light touch
• pain and cold sensations between periodic white finger attacks
• loss of grip strength
• bone cysts in fingers and wrists

The development of hand-arm vibration syndrome is gradual and increases in severity over time. It may take a few months to several years for the symptoms of hand-arm vibration syndrome to become clinically noticeable.

Hand-arm vibration exposure affects the blood flow (vascular effect) and causes loss of touch sensation (neurological effect) in the fingers.

General symptoms include:

• tingling and loss of sensation (numbness) in the fingers
• general pain
• loss or lack of dexterity, difficulties completing tasks that require handling small items 
• sleep disturbances
• difficulty working in damp or cold conditions
• pain in fingers when they recover from blanching, as well as pain and cold sensations between episodes

A common method that is used to classify vibration-induced white finger is the Stockholm Workshop classification scale.

Source: Gemne, G., et al. Scandinavian Journal of Work, Environment and Health. Vol. 13, no. 4 (1987). p. 275-278. And: American Conference of Governmental Industrial Hygienists (ACGIH). 2016 TLVs® and BEIs®. p. 190-194 and 198-204.

The severity of hand-arm vibration syndrome depends on several other factors, such as the characteristics of vibration exposure, work practice, personal history and habits. Table 2 summarizes these factors.

Hand-arm vibration syndrome is also known as Raynaud's phenomenon of occupational origin. Vibration is just one cause of Raynaud's phenomenon. Other causes are connective tissue diseases, tissue injury, diseases of the blood vessels in the fingers, exposure to vinyl chloride, and the use of certain drugs. The resulting reduced blood flow can produce white fingers in cold environments.

Whole-body vibration can cause fatigue, stomach problems, headache, loss of balance and "shakiness" shortly after or during exposure. The symptoms are similar to those that many people experience after a long car or boat trip. After daily exposure over a number of years, whole-body vibration can affect the entire body and result in a number of health disorders. Studies of bus and truck drivers found that occupational exposure to whole-body vibration could have contributed to a number of circulatory, bowel, respiratory, muscular, and back disorders. The combined effects of body posture, postural fatigue, dietary habits, and whole-body vibration are the possible causes for these disorders.

Many studies have reported decreased performance in workers exposed to whole-body vibration.

As in all occupational exposures, individual sensitivity to vibration varies from person to person.

Three important factors affect the health effects that can result from exposure to vibration:

• the threshold value or the amount of vibration exposure that results in no adverse health effects
• the dose-response relationship (how the severity of the ill health effects is related to the amount of exposure)
• latent period (time from first exposure to appearance of symptoms)

The threshold value of vibration is the level below which there is no risk of vibration syndrome. In other words, it is the maximum intensity of vibration to which most healthy workers can be exposed every workday for their entire full-time employment without developing numbness, paleness or chill of fingers. Workers will not be likely to develop vibration-related injuries or disease if their exposure to vibration is maintained at sufficiently low levels.

What has been observed is that the number of affected people increases as the intensity and duration of vibration exposure increases. This type of exposure-response relationship indicates a possible link between health effects and the total amount of vibration energy entering the hands or body. Depending on the intensity of exposure, the symptoms may appear months or years after the start of the exposure.

Since most vibrating machines and tools produce noise, a vibration-exposed worker is likely to be exposed to noise at the same time. Studies of hearing loss revealed that, for equal noise exposure, those with vibration-induced white finger had greater hearing loss than those without vibration-induced white finger. The reason for this effect is not clear.

Canada, British Columbia,  Manitoba, New Brunswick,  Northwest Territories, Nunavut, Quebec, Saskatchewan, and Yukon are the jurisdictions in Canada that have specifically mentioned vibration exposure within their occupational health and safety regulations in terms of worker health or musculoskeletal effects. Nova Scotia and Ontario cover vibration by adopting requirements for protection from physical agents. Prince Edward Island states that they include vibration as part of the employer's duties under the general duty clause.  Alberta and Newfoundland do not explicitly state vibration or physical agents, but exposure would be regulated under the employer's general duty clause to provide a safe workplace. Most jurisdictions do not regulate a specific limit to vibration exposure, but rather state that workplaces must control for vibration where it can cause health or musculoskeletal effects.   To confirm requirements, always check with your local jurisdiction. 

The American Conference of Governmental Industrial Hygienists (ACGIH) has published exposure recommendations for the prevention of hand-arm and whole-body vibration.