An Effective Dose
of NatureThere’s no question that
natural environments
can relieve stress. But
how much outdoor
time is required to reap
this benefit? A Univer-
sity of Michigan team
led by ecologist Mary-
Carol Hunter asked
people to sit or stroll
anywhere that made
them feel they were
interacting with nature,
for however long they
could afford (10 min-
utes minimum), at least
three times a week for
eight weeks. On aver-
age, each outing prod-
uced a 21.3 per cent
per hour drop in the
stress hormone cortisol
(beyond its usual daily
ebb). When nature
experiences lasted 20
minutes or longer, the
cortisol reduction was
bigger than what could
be explained by mere
chance. “So now the
medical community
can ‘prescribe’ dura-
tions that are based
on objective findings,”
Hunter said.Why Workplace
Gratitude MattersFew of us have more
gruelling jobs than
nurses, who work long
shifts caring for people
who aren’t always at
their most polite. Over
three months, a sample
of nurses in Oregon
reported how often
they received gratitude
on the job. During
weeks when they were
thanked more, they felt
more satisfied with
their accomplishments,
which tended to predict
better sleep, fewer
headaches and health-
ier eating. This would
suggest that getting
commended for a job
well done boosts not
only your morale but
also your physical well-
being. So keep an eye
out for chances to
express appreciation for
others’ efforts: it could
help make workers
happier and healthier.How Much Coffee
Is Risky?Drinking coffee is gen-
erally considered safe or
even mildly beneficial,
but that doesn’t mean
there’s no such thing
as overdoing it. A large
observational study
from Australia found
that java fans who drank
more than six cups per
day saw a 22 per cent
increase in the risk of
cardiovascular disease,
compared to those who
drank one or two cups.
(The term “cup” might
have meant different
things to different
respondents but was
presumably around 250
millilitres.) Fortunately,
the body has ways of
telling us it’s reached
its limit. “A lot of people
self-regulate their intake
if they experience jitteri-
ness, headaches, a fast
heartbeat or trouble
sleeping,” said lead
author Elina Hyppönen.
“This helps protect us
from adverse effects.”rd.ca 23(H
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