Ergonomics and health

Because of their small
and flat keyboard and trackpad pointing devices, prolonged use of laptops can
cause repetitive strain injury.[40] Usage of separate, external ergonomic
keyboards and pointing devices is recommended to prevent injury when working for
long periods of time; they can be connected to a laptop easily by USB or via a
docking station. Some health standards require ergonomic keyboards at
workplaces.

The integrated screen often causes users to hunch over for a
better view, which can cause neck or spinal injuries. A larger and
higher-quality external screen can be connected to almost any laptop to
alleviate that and to provide additional "screen estate" for more productive
work.

A study by State University of New York researchers found that
heat generated from laptops can raise the temperature of the scrotum when
balancing the computer on one's lap, potentially putting sperm count at risk.
The study, which included roughly two dozen men aged 21 to 35, found that the
sitting position required to balance a laptop can raise scrotum temperature by
as much as 2.1 °C (3.78 °F). However, further research is needed to determine
whether this directly affects sterility in men.[41]

A common practical
solution to this problem is to place the laptop on a table or desk, or to use a
book or pillow between the body and the laptop. Another solution is to obtain a
cooling unit for the laptop - these units are usually USB powered and consist of
a hard thin plastic case housing 1, 2 or 3 cooling fans (with the entire
assembly designed to sit under the laptop in question) which results in the
laptop remaining cool to the touch, and greatly reduces laptop heat buildup.

Heat from using a laptop on the lap can also cause skin discoloration on
the thighs.[42]