The more I learn, the more I know that I don’t know. And the more I learn, the more I realize how I screwed up this miraculously engineered body God gave me to live in. I learned a little about leptin and ghrelin last year when I was studying for my Fitness Nutrition certification. These two hormones regulate hunger. Leptin is released by fat cells and some other places. It decreases hunger. Ghrelin is released from the stomach lining and it’s job is to increase hunger.
And when we do not live optimally, the we may alter how things work.
A simple description of how leptin and ghrelin work and may not work…
Like almost everyone, I don’t get enough sleep. My biggest issue is that it takes me a several hours to unwind from my day. I really need to sit and do something to numb my brain for a couple hours. Teaching is a very high energy job. It doesn’t look that way, but imagine this…
You are at home and the door bell rings. You open the front door and 30 teenagers come into your living room and sit down. You’re expected to direct their activity for the next hour. (The phrase “herding cats” comes to mind.) You watch to make sure they are paying attention, redirecting them back when they lose attention, make sure they are writing notes, or doing the thing you need them to do. And while you’re explaining something mathematical, watch all the facial expressions looking for clues as to whether they understand. Some won’t be able to articulate what they do not understand. Or they will think they understand, so you have to ask questions to see if they really do. After about 55 minutes, the door bells rings again. Those 30 kids leave and 30 more come in and sit down. This happens every hour for the next six hours.
That’s my day. When I get home, I don’t want to talk. I don’t want to think. I want to eat and sit and watch Netflix for a couple hours. Pretty sure your job is similarly taxing.
So I started reading more about these hormones and sleep. Some things I found were general studies. Others did try to narrow a focus to my sub group – post menopausal overweight. Yes, I know I’m at a healthy weight now, but I was at an unhealthy weight for a lot longer, and while I know I’ve fixed a lot of things, I suspect that my endocrine system might still be ‘in repair’. Also, my clients tend to be busy middle aged women like me. I know that when I don’t get enough sleep, I feel hungrier. I’m sure we’ve all had that happen.
I’ve read conflicting things, which is to be expected. But overall, researchers are usually finding a connection.
“Furthermore, in this sample of overweight and obese post-menopausal women,sleep improvements did not cause greater weight loss in exercisers, nor did they moderate exercise-induced increases in ghrelin or decreases in leptin. Although our findings with baseline sleep are far from definitive, they are intriguing, and beg the question of whether exercise can ameliorate weight gain in women with sleep problems.” http://portalsaudebrasil.com/artigospsb/obes208.pdf
OK, that was from 2007. They couldn’t really find a predictable relationship between sleep, leptin, and ghrelin, but they suspect that regular exercise might reduce the negative effects of sleep deprivation with respect to the hormone fluctuations. That’s good news, I guess.
This one was published online just a few weeks ago. Didn’t read the whole article because I’d have to pay for it.
“…sleep duration is inversely associated with serum leptin and dietary energy intake in postmenopausal women.” Which basically means that we eat more when we don’t get enough sleep. http://onlinelibrary.wiley.com/doi/10.1002/oby.20683/abstract
From 2004, a study of 12 men with only two days of reduced sleep. That’s kind of a major limitation of the study in my opinion, but this is more representative of what’s out there as a whole…
“Short sleep duration in young, healthy men is associated with decreased leptin levels, increased ghrelin levels,
and increased hunger and appetite.” http://isites.harvard.edu/fs/docs/icb.topic197607.files/Due_Wk_11_Nov_28/SPIEGEL_2004.pdf
What they did mention in this study was that while the leptin levels of these men stayed level during the day, they fluctuated more at night. I read something – forgot where – that said our bodies regulate these hormones while we sleep. Maybe it’s more like ‘recalibrating’ than ‘regulation’. If we tinker with the way things are supposed to work, we may recalibrate incorrectly. I think as I get older, my body is more sensitive to things that aren’t calibrated correctly.
Sleep is so important for so many other things besides hunger that getting enough will always be a top priority for me now. It wasn’t a priority for too many years.