Are you burning the candle at both ends?
Sacrificing sleep for a little more time at your desk or due to an overload of household chores?
Ignoring your circadian rhythm is one of the worst things you can do for your health and your overall productivity. It minimizes efficiency and sets you up for a host of health problems.
Emerging research shows that humans have “clock” genes in every organ in the body, which have a powerful effect on our daily reality. Matching your activities to your circadian rhythms is one of the best ways to improve your health and life—but fewer and fewer people are taking advantage of this tool!
This article will give you an overview of circadian function with ten reasons to get with the program and live in a way that sets you up for peak success.
What Does The Natural Circadian Rhythm Look Like?
The circadian process is controlled primarily by the release of hormones. When you wake up in the morning, you get a surge in cortisol that increases blood pressure and gives you energy. Exposure to light shuts off melatonin production (a hormone that induces sleep), resetting the clock for the day. Sex hormone secretion occurs around 9 am and testosterone peaks.
The body warms up through the middle of the day, and reaction time and physical performance peak between 2:30 and 6 pm. Athletic performance, strength, and power output are highest and risk of injury is lowest during this time. Protein synthesis peaks around 5 pm, which means that if you can train right before that, you’ll experience greater muscle growth and faster recovery.
As sunset approaches, body temperature peaks and the hormone leptin is elevated, which will suppress hunger and signal the brain to burn fat when you sleep. Leptin also upregulates the thyroid and triggers changes in mitochondria to produce heat in the body to keep you warm during the night.
Melatonin is secreted around 9 pm getting you ready for sleep. It downregulates neural function, allowing the brain to heal. Once you go to sleep, prolactin and growth hormone are released to burn fat overnight for energy and the reduction of any inflammation.
There are large individual differences in the actual timing of circadian rhythms, which is most influenced by your unique chronotype. Chronotype refers to whether you are more of a “lark”, or morning person, or an “owl”—an evening person. Most people experience shifts in their tendency across their lifetime, such that they are larks as very young children, owls as teenagers, and larks again as they enter their golden years.
Beyond this pattern, people of any age can be larks or owls, however, it’s also possible to completely alter the system via our daily habits such that we experience peak alertness at the wrong times or become chronically tired. In these situations, research suggests that both hormone release and gene activity has been negatively altered. What follows are ten reasons it’s worth the effort to optimize your circadian rhythm.
#1: Better Sleep
The most obvious payoff of a well functioning circadian clock will be that it’s easy to get to sleep at night and you should be able to wake up without an alarm in the morning. Your parasympathetic nervous system will be primed for rest and repair around 10 pm. The stress hormone cortisol will be low and your sleep hormone melatonin will be elevated to help you doze off without a racing mind or anxiety about your to do list.
#2: Less Hunger & Cravings
The first thing that happens when you are sleep deprived is that you experience a big spike in cortisol, which alters your body’s ability to tolerate sugar. This makes your tissues less sensitive to insulin. The next thing that happens is hunger hormones get revved up and cravings for indulgent, high-fat, high-carb foods become almost overwhelming.
Most people give in and eat, often overshooting their calorie needs, and gaining fat over time. Playing to your innate body clock can bypass all this misery, keeping you lean, sane, and healthy in the process.
#3: Better Insulin Sensitivity & Less Diabetes Risk
A series of studies on mice have shown that when clock genes in the liver and pancreas are altered, it becomes impossible for the body to regulate insulin secretion and manage blood sugar levels effectively.
Humans who have habits that contradict their normal circadian pattern will have similar problems, which lead to insulin resistance, problems managing blood sugar, and ultimately, diabetes. Habits such as eating at odd hours (late at night or snacking all day), skipping meals randomly, or depriving yourself of sleep will all alter your clock genes and set you up for metabolic misery.
#4: Less Body Fat
A consistent side effect of insulin resistance is fat gain because the body experiences changes in hunger cues and its ability to burn fat. Additionally, research shows there are even clock genes in fat tissue that regulate the release of the hunger-reducing hormone leptin. When these genes become dysregulated, appetite signals are altered and people tend to eat more at night. The resulting increase in blood sugar and triglyceride levels (fat molecules in the blood) disrupts the brain’s ability to regulate the timing and intake of food. Fat gain and metabolic syndrome soon follow.
#5: Easier Time Building Muscle
There are a couple of ways a well-functioning circadian rhythm affects muscle building. First, muscle building is the result of protein synthesis, which requires the hormone insulin to enable storage of amino acids and nutrients that rebuild tissue and lead to repair.
Additionally, the hormones testosterone, GH, and IGF-1 are enhanced in a well functioning circadian environment. GH actually follows a circadian release pattern with large amounts secreted during sleep and men who sleep according to their chronotype have higher baseline testosterone levels.
#6: Greater Productivity At Work
Chances are you’ve had days when work feels effortless. You’re cognitively engaged the entire time and one task flows into the next. Although having meaningful work plays a role in this peak experience, you can bet that a big factor was that you somehow took advantage of your optimal circadian rhythm.
Research shows that when people work according to their circadian schedule, creativity is enhanced, and efficiency and work quality increase dramatically. The typical 9 to 5 work schedule runs contradictory to this. The best time for peak work output is mid-morning until about 2 pm. Alertness reaches a low point at 3 pm. This is prime naptime or can be spent socializing or on other personal leisure, such as internet time.
Then, getting back to work by 4 pm allows you to take advantage of the afternoon peak in alertness, which can extend through 6 or 7 pm. Naturally, everyone won’t be able to set their schedule up this way, but there are likely little hacks you can use: For example, instead of spending your morning and mid-day time answering email, devote those hours to the harder tasks that require alertness.
#7: Better Hydration
A common effect of an altered circadian rhythm is that the adrenal glands pump out extra cortisol, leading to an elevated cortisol curve that doesn’t drop over the course of the day as it should. This can lead to imbalances in the fluid regulatory hormone aldosterone, which causes large fluctuations in water stores in the body.
Additionally, clock genes in the kidneys affect water retention as well as the body’s mineral levels of sodium and potassium. If these genes are altered due to lack of sleep, night work, or chronic stress, hydration and vascular function can be negatively affected. Although this may not seem like a big problem, it can make or break a hardcore athlete who must perform in the heat and it has long-term implications for heart health.
#8: Better Cardiovascular Health
The heart takes a major toll when you mess with your circadian rhythm. Sleep deprivation significantly alters blood pressure and the effect is greatest in people who already have high blood pressure.
Over the long-term this means less flexible arteries and greater risk of heart disease. And the bad news doesn’t stop there. There are also clock genes in the heart that send signals to the heart before dawn to prepare it for the rigors of being awake.
This daily nudge gives you the energy to get out of bed in the morning, but it also may explain why so many heart attacks occur in the early morning. More research is needed, but current findings show sleeping based on your chronotype will improve regulation of these genes for a healthier, longer lasting heart.
#9: Greater Strength & Power
When your biorhythm is optimized, physical performance peaks between 3 and 6 pm in the afternoon. Joints and muscles are 20 percent more flexible in the evening than the morning and strength is nearly 6 percent higher.
This has implications for beating opponents as well as results from everyday training. For example, one study found that in the past 25 years of NFL games, when East Coast teams have to travel to the West Coast (which is 3 hours earlier) for games that start at 6 pm, they win only 30 percent of the time. Scientists think this is due to the fact that for East Coast players, 6 pm equals 9 pm and the games typically don’t end til close to midnight EST, which is when the body should be resting. Injury risk may also increase in athletes who have to compete or practice in contradiction to circadian rhythm.
#10: Improved Reproductive Health
Regardless of gender, fertility is all about having your body clock in sync. It’s easy to throw the whole thing off: Something as simple as eating late at night can lead to suppressed morning testosterone in men or deregulation of estrogen in women. Interestingly, women who have an intermediate chronotype, meaning they are not a lark or an owl, have altered cycles and a higher difficulty of getting pregnant. Researchers recommend sleeping according to your natural tendency whenever possible and do everything you can to optimize your natural biorhythm.