Humans are genetically programmed with a circadian clock that is set to a 24-hour period and coordinated with the day-night/light-dark cycle. Our circadian clock regulates the circadian rhythm that monitors feelings of sleepiness and wakefulness. Any disruption in our circadian clock has colossal implications on health. A brand new study slated for publication in the journal Science details the ramifications of circadian clock malfunction on metabolism and cell health.
The Cell’s Energy-burning Process
Cells need energy to stay alive. Inside each of our cells are energy factories called mitochondria. Mitochondria control how much energy cells receive when we are resting and have no immediate glucose supply available from food. Our circadian clock works synergistically with mitochondria to activate the cell’s energy-burning process.
“Circadian clocks are with us on Earth because they have everything to do with energy,” said Joe Bass, M.D., lead researcher of the study and Charles F. Kettering professor and chief of the division of endocrinology, metabolism and molecular medicine at Northwestern University Feinberg School of Medicine and an endocrinologist at Northwestern Memorial Hospital. “If an organism burns its energy efficiently, it has a better chance of survival. Cells are most capable of using fuel when the clock is working properly.”
Researchers removed the circadian clocks in a group of lab mice and used a “stress test” to analyze how the clock regulates energy reserves in a fasting state. Mice with their circadian clocks intact showed no defects in mitochondria; however, mice without a circadian clock were unable to metabolize stored energy and had no reserves with which to prevent the depletion of ATP (the cell’s main energy source).
Researchers discovered that the circadian clock acts as the match that lights the cell’s energy furnace. At the tip of the circadian clock match is a compound called NAD+, and mitochondria contain an enzyme called Sirtuin 3. Sirtuin 3 acts as the flint that lights the match. This process is essentially what keeps cells alive during fasting states, such as sleep. Without a circadian clock, the mice had no NAD+ to turn on Situin 3 and activate energy burning during fasting.
Implications on Health
If your cells are not able to burn stored energy, then your body is unable to store burned energy (aka stored fat). The link between circadian rhythm and weight loss is undeniable, and a properly functioning circadian clock could hold the key to weight loss and management. The study also has promising implications for disease prevention, including diabetes. Researchers are enthusiastic that the findings might pave the way for therapies to treat metabolic disorders associated with circadian disruption. While science works to uncover more mysteries surrounding your circadian clock, you can practice good circadian rhythm by aligning with the natural light and dark cycles of the sun and moon. Try to get to bed and rise to wake a little bit earlier, and your circadian clock will be ticking dutifully and healthfully in no time flat.