Sleep: Why Rest Doesn't Always Mean Re-Energize

Feeling tired after a full night's sleep could be due to a number of reasons, ranging from lifestyle factors to medical conditions. Sleep inertia, a natural part of the waking process, can cause grogginess and disorientation, and may last from a few minutes to over an hour. Poor sleep hygiene, such as an inconsistent sleep schedule, excessive screen time before bed, or an uncomfortable mattress, can also contribute to feeling tired after sleeping. Lifestyle factors like insufficient exercise, excessive caffeine or alcohol consumption, and dietary choices can impact sleep quality. Additionally, underlying health conditions such as sleep apnea, insomnia, restless leg syndrome, or chronic fatigue syndrome may be factors. Addressing sleep habits and making lifestyle changes can help improve sleep quality and energy levels.

Why don't I feel energized after sleeping?

Sleep inertia

There is no known biological cause of sleep inertia, but there are three common theories explaining the phenomenon. Some research suggests that sleep inertia is caused by an increase in delta waves in the posterior part of the brain. Delta waves, or slow waves, are most commonly seen in the non-rapid eye movement (NREM) stage of sleep. Sleep inertia may occur when the brain has not yet reduced delta waves in preparation for waking up, or is suddenly awoken during NREM sleep.

Another theory is that sleep inertia is caused by high levels of adenosine, a nucleic acid compound found in the brain, upon waking. Adenosine levels in the brain progressively increase with sleep deprivation and return to normal during sleep. Upon awakening, if there is sleep deprivation, high amounts of adenosine will be bound to receptors in the brain, neural activity slows down, and a feeling of tiredness results.

The third theory is that sleep inertia is caused by a reduction in blood flow to the brain upon waking. Studies have shown that levels of cerebral blood flow (CBF) and cerebral blood flow velocities (CBFV) will take up to 30 minutes to increase and reach daytime levels.

There are several ways to limit the effects of sleep inertia. These include:

• Regularly getting a full night's sleep
• Limiting naps to less than 30 minutes
• Drinking coffee or another caffeinated beverage when you get up
• Exposing yourself to a lot of bright light during the day
• Keeping your bedroom dark, quiet, and cold at night
• Avoiding screen time for two to three hours before bed
• Using a gentle alarm

Poor sleep hygiene practices

• Not having a regular bedtime routine: This includes inconsistent sleep and wake times, which can disrupt your body's natural sleep-wake cycle, known as the circadian rhythm.
• Taking long daytime naps: While short power naps can be beneficial, long naps during the day can interfere with your nighttime sleep, leading to non-restorative sleep.
• Screen time before bed: The blue light emitted by phones, computers, and other electronic devices can suppress the production of melatonin, a hormone that regulates your sleep-wake cycle. This makes it harder to fall and stay asleep.
• Poor sleep environment: A bedroom that is too hot, too bright, or too loud can disrupt your sleep. It's important to maintain a comfortable temperature, minimize light, and reduce noise for optimal sleep.
• Uncomfortable mattress or pillow: Investing in a medium-firm mattress and a comfortable pillow can improve sleep quality and reduce aches and pains in the morning.

Improving your sleep hygiene practices can help you achieve more restful sleep and increase your energy levels throughout the day.

Lifestyle and dietary factors

Diet: Eating a balanced diet rich in nutrient-dense foods is essential for maintaining energy levels. Consume plenty of fruits, vegetables, legumes, and healthy protein sources such as lean meats, fish, nuts, and seeds. These foods provide your body with the necessary nutrients to perform critical functions and can help regulate your sleep. Avoid excessive consumption of ultra-processed foods and added sugars, as they can impair your energy levels and sleep quality.

Nutrient deficiencies: Deficiencies in specific nutrients, such as riboflavin (vitamin B2), pantothenic acid (vitamin B5), and pyridoxine (vitamin B6), have been linked to fatigue. Consult with a healthcare professional to determine if nutrient deficiencies are contributing to your lack of energy and explore appropriate dietary changes or supplements.

Caffeine consumption: While caffeine can provide a temporary energy boost, overconsumption can disrupt your sleep and lead to a cycle of poor sleep and increased caffeine dependence. Limit your caffeine intake, especially after 4 pm, and opt for plain coffee, black or green tea, or natural energy sources like fruits.

Hydration: Staying adequately hydrated is crucial for maintaining energy levels. Ensure you are drinking enough water throughout the day to replace the water lost through bodily functions. Dehydration can lead to lower energy levels and decreased concentration.

Weight management: Maintaining a healthy body weight is essential for overall health and energy levels. Obesity increases the risk of sleep apnea, a common cause of daytime fatigue, and is linked to increased sleepiness. Focus on achieving and maintaining a healthy weight through a balanced diet and regular exercise.

Exercise: Incorporating physical activity into your daily routine can boost your alertness and improve your overall health. Exercise outdoors to benefit from sunlight exposure, which promotes wakefulness and improves mood and cognitive performance. However, it is essential to exercise caution and avoid vigorous exercise when extremely fatigued, as it increases the risk of injury.

Stress management: Chronic stress can lead to fatigue and exhaustion disorder (ED), causing structural and functional changes in the brain and contributing to chronic inflammation. Consider stress reduction techniques or seek therapeutic support to develop strategies for managing stress effectively.

Sleep hygiene: Improving your sleep hygiene, such as maintaining a consistent sleep schedule, creating a comfortable sleeping environment, and limiting mental stimulation before bed, can enhance your sleep quality and leave you feeling more energised in the morning.

Sleep disorders

In addition to these specific sleep disorders, there are also broader issues with sleep hygiene and lifestyle factors that can contribute to feeling tired after sleeping. Sleep hygiene refers to habits that promote restful sleep, and poor sleep hygiene can result from practices such as irregular sleep schedules, long daytime naps, screen time before bed, an uncomfortable mattress, or a sleep environment that is too hot, bright, or loud. Lifestyle factors, such as a sedentary lifestyle, excessive caffeine or alcohol consumption, and dietary choices can also impact sleep quality. Addressing these sleep hygiene practices and lifestyle factors is crucial to improving sleep quality and feeling energized after sleep.

Health conditions

Sleep is essential for overall health, and a lack of sleep can cause a variety of health issues. Even a single night of poor sleep can affect energy levels, and long-term sleep deprivation can worsen many major health conditions.

• Chronic fatigue syndrome: A condition characterised by constant exhaustion, with likely multiple causes.
• Nutrient deficiencies: Deficiencies in specific vitamins (B2, B5, B6) can lead to fatigue, even with sufficient sleep.
• Stress: Chronic stress can lead to exhaustion, and structural and functional changes in the brain, contributing to fatigue.
• Obesity: Obesity increases the risk of sleep apnea, a common cause of daytime fatigue. It is also linked to increased daytime sleepiness.
• Mental health issues: Conditions such as depression and anxiety can cause or be caused by sleep deprivation, creating a reinforcing cycle.
• Other health conditions: Type 2 diabetes, heart disease, certain cancers, Alzheimer's, Parkinson's, PTSD, and somniphobia can all be linked to sleep deprivation.

Additionally, some people may have a unique genetic mutation that causes a condition known as Short Sleeper Syndrome (SSS). People with SSS can function well on fewer than six hours of sleep per night without any negative repercussions. However, this affects only about 1% of the population. For those without SSS, sleep deprivation will likely have negative consequences for their health and energy levels.

Frequently asked questions