We need to exercise more AND spend less time sitting

Lagos - It's well known that too much sitting time is
bad for our health. "What we didn't know was whether
the sitting time and health relationship was because
people were also exercising poorly," said senior author
Dr. David Alter of the Toronto Rehabilitation Institute-
University Health Network and Institute for Clinical
Evaluative Sciences, in a phone interview.
Two distinct factors
It turns out, he and his colleagues say, that sedentary
time and exercise time are two distinct factors when it
comes to health outcomes.
"Another way of saying it is just because one does their
30 to 60 minutes of exercise per day doesn't ensure
their health," Alter said. "These are two distinct factors,
we need both, we need exercise and need to be sitting
less."
The researchers analysed 47 studies that tracked
groups of people as they reported roughly how much
time they spent sitting around and not expending
much energy, as well as how often they exercised.
People who were the most sedentary were more likely
to be diagnosed with type 2 diabetes, breast, colon,
ovarian and other cancers, and cardiovascular disease
than people who spent less time sitting.
They were also 24 percent more likely to die during the
studies than those who spent the least time sitting.
The pattern tended to be more pronounced for people
who also reported less time exercising, the authors
reported in the Annals of Internal Medicine. But
regardless of physical activity level, prolonged
sedentary time was independently associated with bad
health outcomes.
A host of diseases
The studies "all seemed to show a similar result," Alter
said. "There is a strong and consistent link between
sitting time and a host of diseases."
Strategies for encouraging people to sit less are
different than those used to promote exercise, he said.
"There are very simple things we can do, every half an
hour get up for two to three minutes," he said. "You do
that and that's already nearly an hour less sitting per
day."
Standing burns twice as many calories as sitting, he
noted. People can also stand during commercial
breaks while watching TV or during the last 15 minutes
of a sporting event, he said.
These strategies don't replace daily exercise, Alter
stressed.
None of the studies in the review were randomised
controlled trials, so researchers can't yet say that
sitting directly causes disease, Alter said.
Elevated health risk biomarkers
There will need to be considerably more research done
to fill in those gaps and help develop guidelines for
sedentary behaviour, like there are for physical activity,
Neville Owen, programme head of Behavioural &
Generational Change at Baker IDI Heart and Diabetes
Institute in Melbourne, Australia, wrote in an editorial
published with the study.
Even among adults who meet the public health
guideline – that is, they walk at least 30 min a day –
"those who sit for prolonged periods have elevated
health risk biomarkers," Owen told Reuters Health by
email. "However, there is insufficient evidence yet to
know whether very highly active people who sit for
prolonged periods are also at risk."
Regardless, sitting time was most important for non-
exercisers, Alter said.
"Those that do not exercise and who sit a lot, the health
hazards are accellerated quite markedly," Alter said.
"If there is a priority population that I tune myself into,
it's the non-exercisers high-sitting-time people."
SOURCE: http://bit.ly/1i46lF7 Annals of Internal
Medicine,