In April, I got the chance to accompany my wife to a conference on circadian rhythm and metabolic disease (she was presenting a groundbreaking poster on the role of circadian rhythm genes in sebocyte skin cells). The Chancellor of UCLA has a lab studying circadian rhythm science, and I got the chance to hear him speak about his research. The conference took place at the Bruin Woods retreat center in Lake Arrowhead, which was a beautiful location that featured many cool outdoors-y activities like hiking, kayaking, archery, rock climbing, etc. (too bad it wasn't summer time!), and the food was really good too.
While most of the talks were highly technical, I was able to follow some of them and learned a lot about the importance of the circadian rhythm in affecting practically all biological functions. On the flip side, I learned how irregularities in one's rhythm can disrupt and cause many common diseases, especially diabetes (irregular rhythm is stronger indicator of diabetes than weight/BMI!). What that means for you: go to sleep on time to stay healthy!
From an "eastern medicine" standpoint, these findings make sense, as the circadian rhythm is what allows us humans to stay in sync with nature around us. And I can see how in our 24/7, work-a-holic, always-online world, circadian rhythms and "synchronization with nature" can get more easily disrupted.
Below are some of the main lessons I took away from the conference sessions. Here's a recent WSJ article on the topic as well.
- Circadian rhythm regulated by SCN part of brain (across 2 hemispheres)
- 80,000 neurons stay in sync!
- VIP synchronizes, GABA desynchronizes
- Circadian rhythm expressed in most major organs (pancreas, liver, skin)
- Light from eye comes in and gives signal to brain
- Experiments use rat models, fat mice, skinny mice, mice with clock genes knocked out (poor mice!)
- Measure mouse activity by "wheel running" (funny concept; I tried to ask why mice like to run on the wheel but couldn't get a clear answer)
- Clock genes expressed in cells
- Bladder shrinks during the day and grows at night to enable comfortable sleep (cool!)
- Shift workers have higher risk of cancer (!!)
- Melatonin is protective of cancer (and bad circadian rhythm messes up melatonin)
- Messed up circadian rhythm leads to diseases (diabetes, hypertension, metabolic syndrome)
- Messed up circadian rhythm is a stronger indicator of diabetes than BMI (!!)
- High fructose corn syrup (like in soda) lowers mental function in mice
- Bad circadian rhythm + bad diet increases hypertension risk
- Circadian rhythm disturbance leads to metabolic disorders because of dyssynchrony between what body programmed to do and what body does (not in harmony with nature)
- Exercise at specific times on a daily basis can fix a broken circadian rhythm (used timed wheel access for mice)
- Circadian disorders affect memory and learned behavior
- Aging clock: reduction in wheel running amplitude in old mice
- Old adjust more slowly to new light schedules
- Phase advance forward increases mortality for old animals (eastward travel) but phase delay back doesn't (if you're old, try not to fly east!)
- Cool concept: "social jet lag" (going to sleep late Friday and Saturday is like flying west and then waking up early Monday is like flying east)