We know that children are getting less physical activity, but a new
report from a top Psychologist suggests that the act of watching TV
itself has worrying effects on our health. Dr Aric Sigman, who reviewed 35
academic studies, calls television the “greatest unacknowledged health
scandal of our time”.
Our work in Ireland suggests that many Irish children spend more than
four hours per day watching TV. On this basis, the average child will have
spent a full year watching television by the time they are six years old.
Most children in Ireland spend more time watching TV than they spend in
school.
Television watching has a clear effect on human biology. It reduces the
levels of the brain hormone melatonin, which usually increase in the evening
as light levels fall. Staring at a bright screen for hours reduces the
production of melatonin. This may effect the body’s natural rhythm, keeping
you awake longer…and reduced levels of melatonin have even been linked to
early puberty in girls. The age at which girls reach puberty has been
getting younger since the 1950’s, and lower melatonin levels may be one
reason for this. Scientists have begun to link watching more television with
an earlier onset of puberty.
Dr Sigman, a member of the Institute of Biology and associate fellow of
the British Psychological Society, says that watching television also
damages sleep patterns, causes over-eating and increases the risk of type 2
diabetes “Television may induce us to eat more [by] causing our brain to
monitor external non-food cues — the television screen — as opposed to
internal food cues telling us that we have stuffed ourselves and can stop
eating.” Low attention spans and poor educational achievement could also be
linked to television viewing habits.
Dr Sigman, whose work is published in the latest edition of the
peer-reviewed journal Biologist, suggests that limiting TV time should be a
priority to improve children's well-being. Dr Sigman has recommended that
between the ages of three to five children should watch no more half an hour
of 'good quality programming' a day. This could be increased to an hour for
5 to12-year olds and an hour and a half for teenagers. The American Academy
of Pediatrics recommends that children younger than 2 years old should have
no screen time, and that older children should watch 1-2 hours per day at
most.
Scientific studies suggest:
 | Heavy television watching is likely to affect performance in school |
| Adults who watch lots of TV tend to have an increased risk of type II
diabetes and obesity |
| Watching lots of TV in mid-life has been linked to an increased risk
of Alzheimer’s Disease |
| Heavy TV watching may affect children's cognitive development |
| Children with a TV in their bedroom do less well in academic tests |
| Regular exposure to bright light from television suppresses production
of the key hormone melatonin - this suppression may cause early puberty in
girls |
| TV viewing in childhood and adolescence is linked with poor
educational achievement in later life |
| Children who watch lots of TV have a greater risk of becoming
overweight, and children with a TV in their bedroom are at an even greater
risk of this |
| Prolonged TV watching is associated with an increased risk of type II
diabetes, and limiting TV and computer games in children may help to
prevent type II diabetes |
| Girls who watch a lot of TV may be at an increased risk of getting an
eating disorder |
| TV watching has been linked to risk factors for atherosclerosis and
cardiovascular disease in adults |
| TV watching may result in daytime fatigue, with TV viewing in infants
and toddlers being linked to irregular sleeping patterns |
| Adolescents and young adults who watch lots of TV have a greater risk
of sleep problems |
| Melatonin is a powerful antioxidant, and reduced levels of melatonin
may increase the chance of mutations in cell DNA, which causes cancer |
| Slow metabolism - watching TV may slow the metabolism more than simply
doing nothing |
