In my previous post, I wrote about working with our 24-hour, circadian bio-rhythm. In this post, I address the other type of bio-rhythm I mentioned, ultradian bio-rhythms.
Ultradian rhythms, also known as rest-activity cycles, are of 90-120 minute duration. They are characterized by a 60-90 minute activity phase, followed by a 20 minute (approximately) resting phase. Graphically, they look like this:
We go through these ultradian cycles all day long, even in our sleep phase. As shown in the Circadian blog, here is the relationship between our circadian and ultradian bio-rhythms:
During the activity phase these are the periods during the day when you have highest mental and physical energy. During the waking phase the activity phase peaks are left-brain (left-brain cerebral hemisphere) dominant periods. During sleep, performance peaks represent the REM/ dream mode of consciousness periods. The resting phase is very important and to learn to become attuned to.
During the resting phase many important biochemical and physiological processes go along, replenishing our cells and getting our body ready for another activity cycle. Here are some of the more notable ones of the hormonal system:
| Hormone | Half-life*(min) | Release per day | Function |
| Cortisol | 16 | 19 | Released during stress |
| Growth hormone | 25 | 12 | Growth and healing |
| ß-endorphin | 13 | Neuropeptide that reduces pain | |
| Parathyroid hormone (PTH) | 22 | 12 | Regulates blood Ca++ levels |
| Insulin | 60 | 12 | Regulates glucose and energy levels |
| Adrenocorticotropic hormone (ACTH) | 19 | 40 | An anterior pituitary hormone that regulates activity of the adrenal cortex |
Cell division and DNA synthesis, etc. occur during the resting phase. So, while the mind-body is “resting,” our cells are down there taking care of important business during the resting phase. During the resting phase, left-brain dominance drops off, and the right-brain dominates. This shift is important because it allows us to access the more holistic, Gestalt side of our brain. The right brain is a non-linear, creative problem solver.
The right-brain doesn’t “communicate” in a verbal fashion like the left-brain. The right-brain is image driven. Durning the resting phase, we can access more readily that very powerful part of our brain. This is the place of imagery, archetypes, creativity, and insights. Not linear logic as occurs in our left brain, but rather non-linear jumps to solutions and understanding.
I have learned to pay attention to my ultradian cycles during my day, become very much aware when shifts occur bewtween my acting and resting phases, and leaned to take advantage especially of my resting phase. When I feel my energy drop off, I know I am entering a resting phase phase, and try to take a rest.
This is where my 20-minute power naps come in, for example. My early morning meditation sittings are also 20 minutes. It is a normal cycle for me. When I am struggling with problem solving, I welcome the resting phase as often it is during these period that solutions come to me.
I don’t have to lay down and think about the problem. Rather, I lie down, close my eyes, and relax my body-mind. I don’t have to focus on the problem, just let my left brain come up with ideas and possible solutions.