How to Hack your Circadian Rhythm to Improve Your Health
The importance of our sleep-wake cycles on our overall health is an extremely relevant topic that is becoming more and more understood. As humans, we evolved to use this regulatory clock to tell our bodies when to sleep, eat, and perform activities. What’s more important is that our bodies have adapted to provide optimal physiological function at certain times of the day. Understanding how this clock works and implementing strategies to use it as an advantage is essential to optimize function and increase health.
Our sleep-wake cycle, or circadian rhythm is an innate function of human physiology. It is controlled primarily by melatonin, which is released in response to the time of day, our activities throughout the day, and the amount of light that we are exposed to. It tells our body when to sleep, when to eat, when to move, and controls factors to optimize these functions at a particular time of day. We now know that our circadian rhythm also has functions which control every part of the body like metabolism, hormone release, digestion, and energy levels.
When we disrupt this clock through unhealthy lifestyle habits it can lead to many problems down the road. A primary example of this is night shift workers, who have been shown to have an increased risk of diabetes, cardiovascular disease, and cancer (1).
There is no doubt that a normal circadian rhythm is extremely important for optimal function. However, many of us are disrupting this with poor sleep schedules, eating at the wrong time, and other unhealthy lifestyle choices.
Strategies to Optimize Circadian Rhythm
There are many strategies that can be implemented in order to allow the circadian rhythm to work for us rather than against us. These strategies have been shown to be a benefit for many things including weight loss, lowering disease risk, increasing longevity, and improving performance.
Intermittent Fasting
Just like our circadian sleep-wake cycles, the way we digest foods and burn energy has been shown to be on a similar interconnected clock. Humans are built to utilize energy from food to fuel activity at specific times throughout the day (primarily the daytime) in order to ensure higher levels of performance at optimal times. For example, during the daytime we use more blood sugar for energy (higher metabolism), have increased movement of food through the gut, and have more blood flow to the intestines for digestion; showing that our bodies are adapted to have a higher metabolism during the day (1).
In the same way that our bodies are programmed to consume calories during the day in order to efficiently utilize energy, we are also built to fast for a period overnight. This may be seen in studies that show nighttime eating to be associated with poor sleep, insulin resistance, and an increased risk of chronic diseases (2). This may be due to the disruption of our normal circadian rhythm from eating at abnormal times (night eating) (3).
In addition to this, poor sleep-wake cycles may be detrimental to our metabolism and cause an increase in hunger. A study in shift workers who have an altered circadian rhythm showed that this is also associated with abnormal appetite-regulating hormones which may lead to increased caloric intake (4).
The link between our circadian rhythm and food intake goes beyond these reactions. Our healthy gut bacteria may be directly influenced by intermittent fasting to have an effect on metabolism and decrease the risk of obesity. This reaction also goes both ways as jet lag and circadian rhythm have been associated with an “obese gut bacteria” which may cause metabolic complications like glucose intolerance and obesity.
Intermittent fasting may be an excellent strategy to promote an optimal circadian rhythm, returning the body to how it is meant to metabolize energy. To read more about the types and benefits of intermittent fasting, check out my article here.
Eat Less Meals
A very common nutrition myth is that in order to be healthy we must eat several small meals and snacks throughout the day to avoid being hungry. This eating pattern is unnatural and will likely only increase hunger and cravings.
1-3 meals in a smaller period of time (8-12 hours), also known as time-restricted feeding, gives our body a chance to efficiently utilize the energy for activity while limiting weight gain and improving our circadian rhythm (1).
Exercise at An optimal time
As previously mentioned, our circadian clock regulates many systems in the body (like hormones) to promote optimal performance at certain times throughout the day.
One study that looked at how the time of day that exercise is performed affects performance found that men training in the evening gained more more muscle mass (5). This is likely due to the hormonal regulation which is controlled by our circadian rhythm (6)
Another study which looked at exercise before breakfast (fasted cardio) compared to exercise after meals found that those who perform fasted cardio burn more fat throughout the day (7).
These studies may indicate that we are able to use our circadian rhythm to our advantage depending on goals; if looking to burn fat the morning may be the best time for exercise while the evening may be best for muscle growth and performance.
Improve Sleep
Due to the fact that our circadian rhythm is directly correlated with overall health, performance, and metabolism, getting more high-quality sleep is essential for optimal health. Our body is designed take cues from our senses to regulate our sleep-wake cycles including our previous meal, the amount of light we are exposed to, and how much sleep we need.
By limiting meals before bed, avoiding blue light before bed, and practicing good sleep hygiene we are able to normalize our circadian rhythm and optimize health. To read more about strategies to improve sleep quality check out my article here.
Reduce Stress
We already know that stress is a major factor in our overall health and vitality. Abnormal levels of long-term stress may have a detrimental effect on our health by causing excess cortisol production which leads to a dysfunction in our hormonal system (7).
Our bodies are designed to have a stress response as a protective mechanism against danger (think saber-tooth tigers and bear attacks). Our stress response becomes abnormal when our fight-or-flight system is constantly being activated by long-term daily stressors (think work, bills, anxiety, etc.).
Through this hormonal dysfunction, long-term unnecessary stress may cause our circadian rhythm to become abnormal and our sleep quality and health to deteriorate (7). This is a main reason why long-term stress may cause symptoms like fatigue, weight gain, brain fog, and other negative consequences.
We may reduce stress and improve our circadian rhythm and health by implementing many relaxation strategies. Yoga, mindfulness meditation, exercise, and certain lifestyle changes are excellent ways to reduce chronic stress and promote wellness.
The bottom Line:
Our circadian rhythm plays a vital role in our overall health and well-being. It coordinates almost every system in our body and is meant to allow us to perform optimally. When it becomes imbalanced through poor lifestyle habits, we may see a decline in overall wellbeing.
There are many strategies to implement in order to improve our circadian rhythm and improve longevity, performance, wellness, and decrease the risk of many chronic diseases. By implementing these strategies to normalize our circadian rhythm, this can allow us to fully optimize our lives.