Why choosing rhythm may ward off chronic disease
After several days of being on-call this week as an obgyn, I’m reminded of how important our circadian rhythm really is.
Here is my call log from one of these nights on call:
4:57 pm
5:25 pm
6:35 pm
7:11 pm
8:04 pm
9:08 pm
10:54 pm
11:26 pm
1:18 am
1:36 am
3:08 am
The 3:08 am call was when I had to head to the hospital. As you can see, there is not a single two hour span between any of those calls. After that, I was awake for the day though I did take a short nap at some point.
What is the circadian rhythm?
Our circadian rhythm is our natural cycle of waking and sleeping, activity and rest, eating and fasting.
This is physiologic, meaning a normal function of the human body, in response to light. Light enters our eyes and affects something called the suprachiasmatic nuclei.
This part of our brain is responsible for sending signals to the rest of the body for sleep/wake cycles, temperature cycling, and hormone production.
Since our modern world typically involves artificial light, we can easily disrupt this entire system. We have limited exposure to natural daylight and increased exposure to artificial light especially at night.
That may seem harmless but it’s far from it. In fact, it’s a ubiquitous factor in our current chronic disease epidemic.
Any woman, but especially those in midlife, should be taking massive action to stave off chronic illness as long as we possibly can. Chronic illness has become so commonplace that we tend to accept it as fate when actually it doesn’t have to be, and frankly shouldn’t be.
What metabolic effects does circadian rhythm disruption have?
Insulin resistance
If you’ve noticed unexpected weight gain, you’re not alone. You may not have changed anything but the weight adds on. Maybe you’ve noticed a change in how your weight is distributed, it seems to be concentrated around your midsection.
This is due, in part, to insulin resistance. Insulin increases with the hormonal changes of menopause. When our body takes in energy (food), our cells either use it the energy or store it for later. The excess energy is stored as fat, sometimes even within the cells themselves. As this develops, our body is saturated and can’t take more glucose (sugar) out of our bloodstream for use or storage. In response to the high glucose, the body increases insulin levels. It’s really trying! Now we have high glucose, high insulin and cells full of fat.
Sleep disruption worsens this. After just five nights of four hours of sleep or less, insulin resistance increased 24% in one study. The stress hormone, cortisol, was increased. Thyroid hormone release was impaired. It’s metabolic havoc.
Feeding behavior
When I was a resident on a 24 hour shift, we often ordered take out. I would graze all night, not so much for hunger but because of fatigue.
There’s a chemical reason for this. With sleep deprivation, our hunger hormone called ghrelin is increased. Our feeling full hormone called leptin is decreased. I think of this like an intersection where the red light (leptin) won’t work and green lights (ghrelin) are on in all directions. We’ve lost the ebb and flow of hunger and fullness and we live in a world of constant food availability which results in a free for all, a feeding frenzy with no brakes.
Dietary choices
Sleep deprivation gives us more satisfaction from our food choices, even if they aren’t good choices. We’re more sensitive to the high. We feel rewarded.
This is in direct contrast to mindful eating where we should consider our choices, our portions, eat slowly and stop when we are 80% full.
In my world, not only did we eat take out on a 24 hour call, most people have some sort of “post call meal” that is their preference. I have one partner whose fix is Eggo waffles.
What chronic illnesses can result from insulin resistance?
Insulin resistance is the cornerstone of several metabolic disorders, including:
Diabetes mellitus
Hypertension
Obesity
Non-alcoholic fatty liver disease
Chronic kidney disease
Polycystic ovary syndrome
Alzheimer’s disease
Cancers such as breast, endometrial, pancreatic, colorectal
We’ve only scientifically known about insulin for about 100 years. In that short amount of time in the scheme of the human species, we have overwhelmed the human body to the extent that insulin can’t perform it’s usual function and we are riddled with disease.
This isn’t just about eating sugar, though that’s part of the story. Our sleep and our rhythm is inextricably tied to our metabolism and whether we can prevent or succumb to chronic disease.
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Some of the information contained in this article is the result of my training, medical knowledge, and personal experience without a specific source to be cited.
This is not medical advice.
