Ever get that sleepy feeling
around 3pm? You’re not alone, that’s your body’s circadian rhythm talking.
Most adults circadian rhythm
dips and rises at two different times, so adults' strongest sleep drive
generally occurs between 2:00-4:00 am and in the afternoon between 1:00-3:00
pm. There is some variation depending on the lifestyle choices of the individual,
including sleeping and waking hours as well as eating habits. The sleepiness experienced
during these dips may be more or less intense depending on whether they’ve had adequate
sleep in previous days.
The circadian biological
clock is controlled by a part of the brain called the Suprachiasmatic Nucleus
(SCN), a group of cells in the hypothalamus that respond to light and dark
signals. From the optic nerve of the eye, light travels to the SCN, signaling the
internal clock that it is time to be awake. The SCN signals to other parts of
the brain that control hormones, body temperature and other functions that play
a role in making us feel sleepy or awake.
In the mornings, with
exposure to light, the SCN sends signals to raise body temperature and produce hormones
like cortisol. The SCN also responds to light by delaying the release of other
hormones like melatonin, which is associated with sleep
onset and is produced when the eyes signal to the SCN that it is dark.
Melatonin levels rise in the evening and stay elevated throughout the night,
promoting sleep.[1]
In a perfect world we would sleep
when it’s dark and wake when it’s light, providing our bodies with 8-10 hours of quality sleep per night. Unfortunately, for many people this is quite a challenge
because of work, kids, school, etc. Adequate sleep is essential to overall health and that can not be emphasized enough. The impact of not getting
enough sleep is no laughing matter.
Based on this
study having a disrupted biological clock can promote weight gain
of 10 pounds per year due to a decreased metabolic rate and slowed secretion of
insulin. Thereby increasing health risk for type 2 diabetes
and obesity. So the question is how do we avoid the side effects of a sleep deficiency
or disrupted sleep cycle?
1. Aim for quality sleep by
creating a ritual for yourself. Limit light exposure before bed (no TV, or
computer screens) before bed, make sure your room is temperate (somewhere
between 65-70 degrees) for optimal sleep.
2. Make sure your room is DARK and/or
invest in a sleep
mask. This will also be helpful in taking naps when your body really needs one.
The best time to nap is between 1-3pm because of our circadian rhythm.
3. Avoid caffeine and alcohol in the evenings, when
the effect of either wear off your body will wake you. “Alcohol consumption, in excess or too close to bedtime,
diminishes the quality of sleep, often leads to more waking throughout
the night, and lessens time
spent in REM sleep and slow wave sleep in the later part of the night, the deepest
and most restorative phase of sleep.”[2]
4. Exercise during the day to fatigue your
body, most people find that on days they exercise they sleep better!
Life can make it challenging to get enough
quality sleep, and if you can’t sleep “normal” hours because of work it can be
very difficult to stay motivated to achieve your health and fitness goals. Implementing
some of the above strategies can help you to prioritize getting more quality
sleep and doing so should help you reach your goals with gusto! If you need
more help talking through your sleep strategies let’s talk!
Great post! My biological clock will forever be messed up with my work schedule. I think this is why I have gained so much weight since May. Brittany, I really hope I can lose the weight working out with you and making some adjustments to my diet.
ReplyDeleteThank you Sus! Sleep does have a huge impact on our body size & composition, you're schedule could be a likely culprit, but I think you will reach your goals as long you continue prioritizing quality sleep, nutrition and exercise! Over time hopefully your body will find a "new normal." Let's talk about some strategies on Friday!
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