cron-web.org

[A1CR]

Ramadan may provide a model for what happens to our
http://en.wikipedia.org/wiki/Biological_clock when we engage in
http://en.wikipedia.org/wiki/Fasting as occurs in
http://en.wikipedia.org/wiki/Ramadan in some CR regimen. A
previous paper examining the effects of Ramadan in the
http://tinyurl.com/y9vhrr paper, which described for
excerpts in
http://tinyurl.com/yzogf6 should provide relevant details.

Reilly T, Waterhouse J.
Altered sleep-wake cycles and food intake: The Ramadan model.
Physiol Behav. 2006 Oct 30; [Epub ahead of print]
PMID: 17081572

In this review the effects of diurnal fasting on normal
physiological
processes are considered. Ramadan is placed in a circadian
context, food and
fluid ingestion being displaced to the pre-sunrise and
post-sunset hours.
Over the holy month, negative energy balance is often
experienced, though
this deficit is not a universal finding. Responses to
exercise during the
day show influences consistent with hypohydration and an
increased reliance
on fat as a source of fuel for exercise. Muscle performance
and psychomotor
performance are impaired as the month of fasting progresses
but it is not
clear how circadian rhythms in responses to activity are
altered. For some
measures at rest there is a reduction in amplitude and a
delay in acrophase.
Health-related benefits are reflected in a rise in
high-density lipoprotein
cholesterol and individuals with predispositions for
coronary heart disease
are not at increased risk of cardiovascular disorders due to
fasting. The
physiological adjustments during the month have some
similarities to the
disturbances in circadian rhythms experienced in different
circumstances.
The Ramadan model provides an alternative to those for
ageing, nocturnal
shift-work and time-zone transitions in understanding the
links between
behaviour and endogenous circadian rhythms.