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When your brain hasn’t had time to rest and recover, concentration and focus will suffer, as will your ability to connect disparate information and make inferences. This will slow down your thought process and hamper your ability to make decisions.
After a long day of meetings, lunch dates, commuting for two hours, emails, deadlines and making sure the kids get fed and put to bed, it can often feel like your brain is drained and completely depleted of energy. The simplest tasks seem to require monumental amounts of energy, and the idea of making decisions or hard choices sounds like absolute torture.
Every single person reading this has experienced some form of mental tiredness; it is an inherent part of human nature. We have certain amounts of energy that we accrue and expend throughout the day, which allows us to physically move through the world, but you should never underestimate the amount of mental exertion that goes into every day.
Remember, our brain is responsible (ultimately) for every thought, reaction, movement and process occurring in our bodies, mind and physical space from the moment we awake until the moment we go back to sleep. Even while resting, our brain is never completely at rest; it needs to monitor our vital signs, regulate ongoing metabolic processes, and provide the stuff of dreams!
In today’s modern 24-hour world, however, many people are looking for solutions to their decline in cognitive and analytic abilities as they become more tired. Before being able to solve this universal problem, it is essential to first understand it! This begins by understanding how our bodies regulate wakefulness and tiredness.
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If you’ve ever tried to pull an all-nighter, get up at an unusually early hour, or force a nap in the middle of the day, then you understand how strong your Circadian rhythm can be. Also known as the “body clock”, a person’s Circadian rhythm is their internal schedule that determines when the body is tired or awake.
The “tiredness” you feel near the end of the day is linked to the release of a hormone called melatonin, which is triggered by your eyes perceiving lower levels of light (i.e., in the evening, as the sun is setting). On the other hand, we have serotonin, a neurotransmitter that makes us feel good and keeps us energized in the morning while we are overcoming our drowsiness from the sleep state. Melatonin, serotonin and other hormones/neurotransmitters are the driving forces behind our daily rhythms.
Conveniently, our Circadian rhythm tends to repeat every 24 hours or so, as they are closely aligned to the rising and setting of the sun. The main period of tiredness, during which we sleep, is the body’s opportunity to repair and recover from the stresses of the day. Essentially, sleep is a chance for the body’s batteries to recharge, which is necessary if you want the “machine” to operate at peak performance.
Now, Circadian rhythms are not the same for everyone; your peaks of morning energy and valleys of post-meal drowsiness will not be identical to others around you. As the Circadian rhythm model shows, there isn’t necessarily a full tank in the morning that gradually becomes depleted. Different people may have different times of day where they feel focused and energized, while at other times, they may feel distracted, disinterested, or in dire need of a nap.
If you consistently deprive yourself of proper amounts of sleep, or if you are actively fighting against your Circadian rhythms, you can begin to build up a sleep deficit. This can result in chronic tiredness, during which your body is constantly playing catch up. This can send you into a state of chronic fight-or-flight, which has a very powerful impact on your cognition and analytical skills.
Also Read: Why Do We Sometimes Feel Tired All Day, But Wired At Night?
Tiredness And Cognition
We rarely think about the brain as a muscle, but that is precisely how it behaves in a number of ways. Just as we must give our body a break after exercising, we need to occasionally give our brain a rest as well. Research has found that engaging in both physically and mentally demanding tasks will increase our body’s sense of exhaustion, more than the physical activity alone. Mental tiredness and exhaustion are very real, and can have many side effects, some of which are quite serious!
Slow Thinking – When your brain hasn’t had time to rest and recover, concentration and focus will suffer, as will your ability to connect disparate information and make inferences. This will slow down your thought process and hamper your ability to make decisions.
Depressed Reaction Times – Perhaps the most dangerous effect of tiredness on the body and mind is depressed reaction times. While this may only appear as a slight hesitation when answering a question, it becomes far more dangerous if you’re driving a car or taking care of a child.
Neuronal Function – Studies have conclusively shown that neurons don’t function as efficiently when the body is in a state of exhaustion or chronic tiredness. If your body is starting each day at a deficit, it will always seem like the tank is being gradually emptied throughout the day, regardless of your Circadian peaks and valleys.
Learning Difficulties – As most adults know, learning doesn’t stop at college graduation, and we are required to continue learning throughout our lives, whether it is about new technologies or expanding our perception of social and interpersonal cues. However, when our brain is not rested, we struggle to learn things and retain new information.
Memory Impairment – If the brain’s resources are depleted, its ability and ease to recall memories—both from long- and short-term memory—will be impaired.
Mood and Behavior – Regulating your mood when you are tired becomes very difficult, as your hormonal balance will likely be skewed and the fight-or-flight state of your chronically tired body might make you more nervous, aggressive, jumpy or indecisive. If you want to show up at your best every day, ensure that you have enough sleep and a good understanding of your personal energy cycle.
Does Age Have Anything To Do With It?
As mentioned above, Circadian rhythms come in all shapes and sizes, and can also be altered (slowly and responsibly) by changing your behavior. For example, if you get a new job that demands getting up two hours earlier, it might take a few weeks, but your body will eventually adjust to this newly established routine. However, you’ve probably also heard the phrase “early riser” or “night owl”; while those don’t sound overly scientific, people do tend to fall into one of these two categories.
Some people want to get up with the sun and get busy, accomplishing their tasks earlier in the day, typically peaking around late morning, and then winding down for the remainder of the day, and likely going to bed somewhat early. Other people are slow to get out of bed, enjoy sleeping in, and often don’t start being productive until the afternoon, or even later, stretching their social, mental and physical capital later into the evening. There is not necessarily a “right” or “wrong” to this, but it is best to listen to what your body is telling you to do—unless it always says “Sleep in and skip work”.
For generations, parents have been telling their kids that they’re lazy and need to get up and start moving. However, recent research has shown that adolescents and young adults, often lasting into the mid-20s, are more prone to be night owls. In fact, the Circadian rhythms of younger people are, on average, about 2-3 hours behind that of adults. In other words, it makes sense why teenagers and college students can stay up until 3am and then sleep in ’til noon, while their professors’ bodies may demand a strict 7am rise and 10pm bedtime!
Also Read: Why Do We Wake Up At Roughly The Same Time Every Morning?
A Final Word
It is important to remember that, despite all being on a 24-hour cycle, no two humans will ever have the exact same brain chemistry, life schedule or Circadian rhythm. Once you identify the ebb and flow of your own day, and ensure that you get enough restful sleep on a daily basis, you can tailor your behavior and energy expenditures accordingly. Schedule your mentally demanding tasks for when you feel most alert and clear-headed, and be more active and mobile when you are feeling antsy or mentally depleted.
While it is possible to manipulate your cycles of tiredness and wakefulness in a gradual manner, drastic changes or constant fluctuation can be exhausting for the body. Paying attention to your natural cycles will give you insight to leading a more productive, cognitively engaged and energetic life!
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References (click to expand)
- Effects of Mental Fatigue on Brain Activity and Cognitive .... longdom.org
- Blatter, K., & Cajochen, C. (2007, February). Circadian rhythms in cognitive performance: Methodological constraints, protocols, theoretical underpinnings. Physiology & Behavior. Elsevier BV.
- Circadian Rhythms and the Brain | Harvard Medical School. Harvard Medical School
- Kerkhof, G. A. (1985, March). Inter-individual differences in the human circadian system: A review. Biological Psychology. Elsevier BV.
- Foster, R. G., Peirson, S. N., Wulff, K., Winnebeck, E., Vetter, C., & Roenneberg, T. (2013). Sleep and Circadian Rhythm Disruption in Social Jetlag and Mental Illness. Progress in Molecular Biology and Translational Science. Elsevier.
- Blue light has a dark side - Harvard Health. Harvard University