These four OTs are short for "overtime", which means overtime. Four common types of overtime are routine overtime, weekend overtime, holiday overtime and night overtime.

Overtime at ordinary times refers to working overtime on weekdays, exceeding the prescribed working hours. Overtime on weekends means overtime on Saturdays and Sundays, overtime on legal holidays means overtime on legal holidays, and overtime at night means overtime at night.

Overtime may have negative effects on the body, including lack of sleep, physical fatigue and excessive mental stress. Excessive overtime may also lead to organ dysfunction, which has a serious impact on health.

In order to avoid the negative impact of overtime on health, we should adopt scientific and regular overtime methods and arrange working hours and rest hours reasonably. Proper physical exercise also helps to restore physical function.

Enterprises should take effective measures to avoid excessive overtime. The first step is to arrange the work plan reasonably to avoid overtime caused by improper work arrangement. Secondly, it is necessary to improve the system regulations, clearly stipulate overtime hours, and provide corresponding reward systems.

In addition, employees should be trained and educated to make them aware of the negative impact of overtime work on their health and be willing to work overtime as little as possible after completing their tasks, which is beneficial to their health.