This is not strictly breastfeeding related, but is thought provoking in
relation to new motherhood [certainly a sleep depriving time of life] and
why women do the mothering instead of the men.

Gail S. Hertz, MD, IBCLC
[log in to unmask]

Mild sleep deprivation alters hormonal activity

SAN FRANCISCO (Reuters Health) - Just a few hours of sleep deprivation
could impair daily functioning and affect hormonal levels in the body,
researchers reported here Saturday at the annual meeting of the Endocrine
Society.

"Even modest sleep restriction affects hormones," said Dr. Alexandros
Vgontzas, a professor of psychiatry at Pennsylvania State University in
Hershey.

While severe sleep deprivation has been repeatedly shown to have harmful
effects on mental and physical functioning, many scientists do not believe
mild amounts of curtailed sleep will do much damage. "They believe it is no
big deal," Vgontzas noted.

"We decided to mimic real life by restricting normal sleep by two hours for
a week."

Vgontzas and colleagues at the National Institutes of Health studied 25
young healthy men and women who agreed to spend 12 consecutive days in a
sleep laboratory.

The first four nights, they were allowed to sleep for up to eight hours.
The remaining nights, the study participants were woken after they slept
for six hours.

After a week of mild sleep deprivation, the researchers measured changes in
study participants' quality of nighttime sleep, daytime drowsiness,
hormonal activity as measured by continuous blood sampling and hourly
performance on a vigilance test.

After one week of sleep deprivation, as expected, the study participants
fell asleep faster and slept more deeply, a sign of the body's attempt to
adapt to the sleep loss.

And during the daytime, the sleep-deprived individuals showed more signs of
sleepiness and performed worse on a vigilance test.

In addition, researchers found that sleep deprivation affected hormonal
levels.

Men and women had a 40% to 60% average increase in the inflammatory marker
interleukin-6 (IL-6), while men alone showed a 20% to 30% increase in
another marker for inflammation, tumor necrosis factor (TNF).

Both IL-6 and TNF are cytokines, which are proteins the body releases in
response to injury.

"Women seemed to fare better; they were more resilient," Vgontzas noted. In
addition to not producing higher levels of TNF, they were able to sleep
more soundly, getting 70 minutes of deep sleep, or rapid eye movement (REM)
sleep, compared to the 40 minutes obtained by men.

The findings indicate that getting a full night's rest of eight hours on
top of a base of six or so hours is not a nice bonus, but necessary,
Vgontzas said.

"There is no 'optional' sleep," he said. "Those two to three hours are
important for functioning during the day."

In addition, the finding that lack of sleep may stimulate an increase in
chronic, low-level inflammatory response is worrisome, because that state
has been linked to conditions such as high blood pressure, heart disease
and most recently, diabetes, Vgontzas said.

"Restriction of sleep a few hours is a major risk for public safety," he
warned.

By Melissa Schorr
Copyright 2002 Reuters Limited.
http://www.reutershealth.com/archive/2002/06/24/eline/links/20020624elin028.
html

             ***********************************************
The LACTNET mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software together with L-Soft's LSMTP(TM)
mailer for lightning fast mail delivery. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html