Sleep Science: Optimal Daily Hours For Humans

Sleep is an essential part of our lives, and the amount of sleep we get can have a significant impact on our health and well-being. While the recommended amount of sleep varies across different age groups, it is generally agreed that most healthy adults need between 7 to 9 hours of sleep each night. However, individual needs may differ, and some people may require more or less sleep to function optimally. Understanding how much sleep we need and prioritizing getting enough sleep is crucial for maintaining our physical and mental health.

Sleep recommendations by age

Sleep is essential for the mental and physical health of both children and adults. The amount of sleep needed varies depending on age, family schedules, and individual temperament. Here are the recommended sleep durations for different age groups:

Newborns (0 to 3 months)

Recommended sleep range: 14 to 17 hours per day

In their first few months, newborns don't have a circadian rhythm, so they sleep and wake up at irregular intervals throughout the day and night. They also have tiny stomachs and often wake up hungry.

Babies (4 to 11 months)

Recommended sleep duration: 12 to 16 hours, including naps

As babies start to differentiate between day and night, they'll begin to fall into a sleep rhythm. At this age, they usually sleep about six to eight hours at night, in one block if you're lucky. The rest of their sleep time is made up of naps, with some babies taking one or two, and some taking up to three.

Toddlers (1 to 2 years)

Recommended sleep duration: 11 to 14 hours, including naps

As toddlers become more mobile and vocal, their sleep needs change. They start to sleep longer at night and take fewer naps, usually just one per day. Toddlers often stick to a strict routine, so establishing consistent sleep habits and boundaries is important.

Preschoolers (3 to 5 years)

Recommended sleep duration: 10 to 13 hours, may include a nap

Children in this age group often drop their afternoon naps and get most of their sleep at night. This process is usually gradual, with children napping on alternate days or napping for a few consecutive days and then not napping for a few days. It's important to build some quiet time into their afternoons so they can relax and recharge.

School-aged children (6 to 12 years)

Recommended sleep duration: 9 to 12 hours

When children start school, getting enough sleep is crucial for their learning and performance in the classroom. Insufficient sleep can lead to problems with concentration and behaviour. It can also impact their participation in sports and other extracurricular activities.

Teenagers (13 to 18 years)

Recommended sleep duration: 8 to 10 hours

Teenagers have busy lives, balancing school, jobs, extracurricular activities, homework, and socialising. It's common for teens to be sleep-deprived, which can affect their driving abilities and increase the risk of drowsy driving crashes.

Sleep quality

Bedroom Environment

A comfortable bed, mattress, and pillow are essential for a good night's sleep. A medium-firm mattress may be a good choice to avoid back pain and improve sleep quality. It is also important to consider noise level, ventilation, light, and the level of allergens or carbon dioxide in the air. Keeping the bedroom temperature between 65 to 68 degrees Fahrenheit is ideal for most people.

Light Exposure

Increase your exposure to bright light during the day, as it can improve your daytime energy and nighttime sleep quality and duration. Spending time in natural sunlight or using artificial bright light devices or bulbs can help keep your circadian rhythm healthy. However, reduce blue light exposure in the evening, especially from electronic devices like smartphones and computers, as it can negatively impact your melatonin levels.

Caffeine and Alcohol

Avoid consuming caffeine and alcohol close to bedtime. Caffeine reduces total sleep time and overall sleep efficiency, while alcohol negatively affects sleep quality and hormone levels.

Sleep and Wake Consistency

Consistency in sleep and wake times can aid long-term sleep quality. It helps your body's circadian rhythm, which functions on a set loop aligned with sunrise and sunset.

Relaxation Techniques

Practicing relaxation techniques such as mindfulness, meditation, deep breathing, or visualization before bed can improve sleep quality and are also used to treat insomnia.

Exercise

Regular physical exercise can improve sleep quality, but avoid intense exercise close to bedtime as it may hinder your body's ability to settle down before sleep.

Diet

Avoid eating late at night, as it may negatively affect sleep quality. High-carb foods tend to have a worse impact on sleep than low-carb foods. Also, limit fluid intake late in the evening to prevent excessive urination during the night, which can disrupt sleep.

Sleep disorders

Sleep is a complex biological process that is critical for both physical and mental health. While the exact amount of sleep needed varies across age groups, most healthy adults need at least seven hours of sleep each night. Sleep disorders are conditions that disturb normal sleep patterns and can have detrimental effects on overall health and daily functioning. Here is an overview of some common sleep disorders:

Insomnia

Insomnia is the most prevalent sleep disorder, characterised by difficulty falling and staying asleep. It can cause significant distress and impair daily functioning, with approximately one-third of adults experiencing insomnia symptoms and 4-22% meeting the criteria for insomnia disorder. Insomnia often co-occurs with other mental disorders, with an estimated 40-50% of cases having another mental disorder.

Sleep Apnea

Sleep apnea is a breathing disorder where individuals temporarily stop breathing during sleep, often resulting in snoring, snorting, or gasping for air. This disorder can cause repeated awakenings and lead to daytime sleepiness and fatigue. Sleep apnea is typically diagnosed through a clinical sleep study and can be managed through lifestyle changes, mouthpieces, or CPAP devices.

Restless Leg Syndrome (RLS)

RLS involves an irresistible urge to move the legs, usually accompanied by unpleasant sensations such as tingling or prickling. These symptoms typically occur at night and can be relieved by movement. RLS can disrupt sleep and cause daytime sleepiness, affecting up to 3% of the population.

Hypersomnia

Hypersomnia is a condition where individuals experience excessive sleepiness during the day, even after getting sufficient sleep. People with hypersomnia may find it challenging to stay awake and may unintentionally nap throughout the day. This disorder can cause significant distress and impair concentration and memory.

Circadian Rhythm Disorders

Circadian rhythm disorders occur when an individual's sleep-wake cycles are misaligned with the external light-dark cycle. This misalignment leads to ongoing sleep problems and extreme daytime sleepiness, causing distress and functional impairment. These disorders can be caused by internal factors, such as a person's unique body clock, or external factors like shift work or jet lag.

Parasomnia

Parasomnia involves unusual behaviours during sleep, such as walking, talking, or eating. This category includes various disorders such as sleepwalking, sleep terrors, nightmare disorder, and REM sleep behaviour disorder. These disorders can cause distress and impact social relationships and work life.

Sleep and health

Sleep is essential for health and well-being. The amount of sleep one needs changes throughout their lifetime and is influenced by various factors, including age, daily activities, and overall health. Here are some insights into the relationship between sleep and health:

Recommended Sleep Duration:

According to the American Academy of Pediatrics and the Centers for Disease Control and Prevention (CDC), the recommended sleep duration varies with age:

• Birth to 3 months: 14 to 17 hours
• 4 to 11 months: 12 to 16 hours
• 1 to 2 years: 11 to 14 hours
• 3 to 5 years: 10 to 13 hours
• 6 to 12 years: 9 to 12 hours
• 13 to 18 years: 8 to 10 hours
• 18 to 64 years: 7 to 9 hours
• 65 years and older: 7 to 8 hours

Sleep Quality and Health:

The quality of sleep is just as important as the quantity. Poor sleep quality can increase the risk of diabetes, heart disease, stroke, and mental health issues such as anxiety and depression. It can also lead to higher daytime fatigue, making it challenging to enjoy daily life. Maintaining good sleep quality involves factors such as a consistent wake time, limited daytime naps, and regular physical activity.

Sleep Deprivation and Health:

Not getting enough sleep can have both short-term and long-term impacts on physical, emotional, and cognitive health. Short-term effects include dark circles under the eyes, while long-term sleep deprivation can lead to reduced immunity, high cortisol levels, skin changes, and chronic inflammation. It can also affect one's mood, making individuals cranky, irritable, and less equipped to handle stress and emotions.

Individual Variation:

It's important to recognize that sleep needs vary from person to person. Some people may need less than seven hours, while others might require more. Individual differences can be attributed to factors such as overall health, daily activities, and sleep patterns. Reflecting on personal sleep needs and making adjustments accordingly is essential for maintaining optimal health.

Strategies for Better Sleep:

To improve sleep quality, it's recommended to maintain a consistent sleep schedule, even on weekends. Having a relaxing bedtime routine, optimizing your bedroom environment, and disconnecting from electronic devices before bed can also enhance sleep quality. Additionally, monitoring caffeine and alcohol intake and seeking medical advice if sleep issues persist are crucial steps toward achieving restful sleep.

Improving sleep

Sleep is essential for good health, and there are many ways to improve your sleep quality. Here are some detailed tips to help you sleep better:

Stick to a Consistent Sleep Schedule

Go to bed and wake up at the same time every day, even on weekends. Maintaining a regular sleep schedule helps regulate your body's internal clock and enhances the quality of your sleep.

Get Daily Exercise, but Avoid Intense Workouts Close to Bedtime

Daily exercise can promote better sleep by regulating energy and body temperature. However, avoid intense physical activity close to bedtime as it may hinder your body's ability to settle down for sleep. Aim for at least 20 minutes of daily exercise, preferably earlier in the day.

Get Natural Sunlight Exposure

Try to spend at least 30 minutes outdoors in natural sunlight every day. Sunlight has a strong effect on regulating your body's internal clock, known as the circadian rhythm. If you cannot get natural light, consider using a light therapy box after consulting with your doctor.

Limit Caffeine and Nicotine Intake

Caffeine and nicotine are stimulants that can disrupt your sleep. Avoid consuming caffeinated beverages, such as coffee, tea, and soda, after 2 p.m. or at least 6-8 hours before bedtime. Similarly, refrain from using nicotine products close to bedtime, as they can interfere with your sleep quality.

Avoid Napping Too Late in the Day or for Too Long

Napping after mid-afternoon or taking long naps can disrupt your nighttime sleep. Keep naps short, preferably around 20 minutes, and avoid napping too close to bedtime.

Refrain from Alcohol and Large Meals Close to Bedtime

Consuming alcohol or eating a large meal before bedtime can hinder deep, restorative sleep. Alcohol may induce drowsiness but can lower sleep quality. Finish dinners a few hours before bedtime, and opt for a light evening snack if needed.

Create a Conducive Sleep Environment

Optimize your bedroom environment by keeping it cool, dark, and quiet. Use blackout curtains, earplugs, or white noise machines to minimize light and noise distractions. Set your thermostat to a comfortable temperature, typically between 65 to 68 degrees Fahrenheit.

Engage in Relaxing Bedtime Activities

Instead of using electronic devices, opt for relaxing activities before bed. Reading a book, listening to soothing music, stretching, or practicing relaxation techniques like controlled breathing or meditation can help calm your mind and prepare your body for sleep.

Invest in a Comfortable Mattress and Bedding

Ensure you have a supportive mattress, pillows, and bedding that suits your preferences. A comfortable bed that provides proper spine support can improve your sleep quality and reduce aches and pains.

Disconnect from Electronic Devices Before Bed

Using electronic devices like smartphones, tablets, or laptops before bed can keep your brain wired and make it difficult to wind down. The light from these devices can also suppress melatonin production. Try to disconnect from electronics at least 30 minutes to an hour before going to bed.

Consult a Healthcare Professional if Needed

If you consistently struggle with sleep despite your efforts, consider consulting a healthcare professional. They can help identify any underlying sleep disorders or conditions and provide personalized advice and treatments to improve your sleep.

Frequently asked questions