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Boosting immune system 5​

Such added stress increases the
production of the hormone cortisol in
the body, which in turn can suppress
the immune system. Calming
activities minimize stress, reduce
cortisol production and enhance the
immune system’s function.
Practicing mindfulness and
stepping away from what’s causing
anxiety can help us stay grounded.
(See “Managing stress,” on page 7).
Exercises that have calming or
meditative qualities, such as qi gong
and yoga, also are beneficial and can
easily be done at home. Video calls
can help us stay connected to loved
ones and reduce the stress of not
being able to get together in person.
Sleep
The interaction between the immune
system and sleep is a two-way street.
When your immune system response
kicks in, it changes your sleep. You
may find yourself sleeping longer, for
example, as your immune system
stages an attack against a virus.
On the flip side, when you don’t get
enough sleep, your immune system
can be altered. When you’re not
sleeping well, you may notice that you
get sick more easily. Getting adequate
sleep can help support the way your
immune system functions by
increasing the number of immune
cells circulating in your body.
Sleep has been associated with
reduced infection risks, improved
infection outcomes and better
vaccination responses. Getting
adequate sleep before receiving a
vaccination can double the immune
response in humans. Animal studies
have shown that increasing the length
of sleep positively affects infection
outcomes.
Lack of sleep appears to be a trigger
of low-grade inflammation and related
diseases. Studies in humans on the
relationship between sleep and
infection link shorter sleep duration
with increased risk of pneumonia and
respiratory infections. The amount of
sleep the immune system needs to
function properly is very individual.
But if suboptimal sleep is leaving you
tired and run-down, it’s likely that
your immune system is feeling the
same effects. (See “Breaking the
disrupted sleep cycle,” page 8.)
Slow and steady
It would be really great if we all could
make major lifestyle changes with a
little willpower and a flip of the
switch. But we might as well be honest
— that expectation isn’t logical or
reasonable. It sets us up for
disappointment and reinforces the
negative mindset many of us have
about our ability to change.
When we set big goals for ourselves
that require sudden, drastic changes
to our daily lives, those changes might
last for a day or two but not much
longer. We might be able to maintain
an austere diet, an intense fitness plan
or a dramatic sleep program for a
while. But these extreme behaviors
usually don’t become enduring habits.
In moments of stress or exhaustion,
we quickly regress to our old habits
because they’re easier and they’re
what we’re used to. The next morning,
we wake up with a feeling of failure
that discourages us from reaching our
earlier goals.
Something I frequently ask patients to do is walk 10,000 steps every day. This
has been a popular trend for a while now and it’s a good one. You can even
download apps on your phone or wear activity monitors that help you measure
your steps. But why 10,000 steps?
Because that’s right around the number that achieves the greatest reduction
in premature deaths before the effects start to level off. A JAMA study
published in 2020 showed that increasing daily steps reduced the mortality
rate from any cause, but more specifically from heart disease and cancer.
The average American walks just under 5,000 steps a day. In the study,
making the change from 4,000 daily steps to 8,000 steps led to the steepest
decline in mortality. After about 8,000 steps for women and 12,000 steps for
men, the benefits started to plateau. Older adults benefited the most since
they’re at the highest risk. The study also showed that walking fewer steps, but
speeding up every so often, can provide about the same benefit as walking
more steps at a steady rate.
Steps per day and mortality rate in U.S. adults over 40
DOES COUNTING STEPS HELP?
Steps per day
25
15
5
20
10
0
0 2K 4K 6K 8K 10K 12K 14K 16K
Mortality rate*
*Per 1,000 adults a year
Based on JAMA. 2020;323:1151.
Understanding Immune System Health 4