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How much sleep do you need?

Lindsay Modglin

Sleep isn't just downtime for your body — it's vital for maintaining good health and preventing diseases. However, many adults with hectic lives and demanding schedules aren't getting the rest they need. The amount of sleep you need isn't as cut-and-dried as you might like to think, so determining your personal sleep needs can be a bit of a guessing game.

The thing is, getting a good night's sleep isn't just about how many hours you spend in bed. The quality of your sleep matters just as much, if not more, than the quantity. A good night's sleep consists of a combination of enough time in bed and uninterrupted, restorative sleep cycles. These cycles allow your body to undergo many important processes, including repairing tissues, synthesizing proteins and releasing hormones that regulate growth and stress. So, how much sleep do you need to reap these benefits? Let's break it down.

According to the National Sleep Foundation, sleep recommendations vary significantly across age groups:

  • Infants ages 0-3 months require about 14-17 hours of sleep daily.

  • Toddlers ages 1-2 years need approximately 11-14 hours of daily sleep.

  • Children ages 3-5 years should aim for 10-13 hours.

  • Older children ages 6-13 years require 9-11 hours.

  • Teenagers of 14-17 years need 8-10 hours.

  • Adults (18-64 years) typically need 7-9 hours of sleep.

  • Older adults (65+ years) might find their optimal range to be 7-8 hours.

Research also suggests that women often require slightly more sleep than men due in part to hormonal fluctuations and differences in brain structure, which can affect overall rest needs, says Shelby Harris, a licensed clinical psychologist specializing in behavioral sleep medicine and the director of sleep health at Sleepopolis.

That said, your body's needs may vary from these general recommendations. The best way to determine your ideal sleep duration is to observe how you feel and perform after different amounts of rest.

Sleep stages can also play a role in determining the quality of sleep you're getting and how much you really need. Sleep stages refer to the different stages of sleep that your body goes through each night. The two main types of sleep are Rapid Eye Movement (REM) and non-REM (NREM). Non-REM sleep includes three stages: light sleep, deep sleep and very deep sleep.

Each stage is imperative for your body's restorative processes — light sleep helps with memory consolidation, deep sleep aids in physical recovery and immune function and REM sleep is essential for emotional regulation and cognitive performance. Insufficient duration or disruption in these stages can lead to impaired alertness, mood disturbances and a general decline in health.

Acute sleep deprivation refers to short-term sleep loss, typically lasting a few days or less. It occurs for many reasons, including stress, illness, travel or lifestyle choices. While the impact of acute sleep deprivation varies from person to person, Harris says the following symptoms are common among those who aren't getting enough rest:

  • Difficulty concentrating

  • Impaired memory

  • Mood changes, including irritability, anxiety or depression

  • Decreased reaction time

  • Headaches

  • General fatigue

  • Stress

It's hard to identify any area of health or functioning that wouldn't be negatively affected by chronic sleep deprivation, Jade Wu, a sleep psychologist and Mattress Firm's sleep health expert, tells Yahoo. Many studies have shown that chronic sleep deprivation can lead to increased cortisol levels (a stress hormone), weight gain, increased blood pressure and various other health complications.

Chronic sleep deprivation weakens the body's defenses and increases the risk of illnesses, including the flu and common cold. According to a study that analyzed the data from the hospital records of more than 600,000 people, those diagnosed with insomnia (one of the primary causes of chronic sleep deprivation) were more likely to develop a respiratory infection.

Chronic sleep deprivation is associated with an increased risk of several chronic illnesses, including heart disease, diabetes and cancer. The American Heart Association reports that insufficient sleep can contribute to high blood pressure, inflammation and an increase in stress hormone levels, all of which can be factors in developing heart disease.

Research also suggests that insomnia can disrupt insulin production and glucose metabolism, leading to a 30% increased risk of developing type 2 diabetes. Additionally, a study published in the Journal of Sleep Research found that insomnia is associated with a 24% increase in overall cancer risk.

These aren't the only chronic illnesses linked to chronic sleep deprivation — others include stroke, central nervous system disorders and chronic pain.

When your body doesn't get enough rest, it produces more ghrelin (a hormone that stimulates appetite) and less leptin (a hormone that suppresses appetite). This can lead to increased food cravings and overeating, ultimately resulting in weight gain. Chronic sleep deprivation has been linked to an increased risk of obesity, since it can disrupt the body's metabolic processes and make it harder for the body to regulate energy intake and expenditure.

Research has consistently shown that sleep deficiency increases the risk of developing depression, anxiety and other mood disorders. Impulse control, emotional regulation and decision-making skills are also negatively affected by lack of sleep, making it harder to cope with daily stressors and regulate emotions. Over time, mental health issues can worsen and become more challenging to treat — especially when the root cause of your sleeplessness isn't addressed.

Sleep plays a crucial role in consolidating memories and processing emotions, all of which are essential for optimal performance. According to Wu, lack of sleep can also affect mental and physical performance. In particular, it can lead to decreased reaction time, impaired decision-making skills and reduced overall cognitive function.

Experts say that sleep deprivation is responsible for up to 21% of fatal road accidents. Dr. Greg Hammer, a professor, physician, anesthesiologist and author at Stanford University School of Medicine, tells Yahoo that older adults are even more susceptible to fatigue-related accidents due to poor decision-making skills when drowsy. Additionally, insufficient rest can lead to workplace accidents related to decreased alertness and impaired motor skills.

Tracking your sleep can help you understand whether you're getting enough rest and identify any patterns or issues impacting your sleep quality. Some popular methods of tracking sleep include:

  • Wearable fitness trackers that can monitor your sleep cycles and provide data on sleep duration, efficiency and quality. Available options include watches, wristbands, headbands and rings.

  • A sleep diary to track the time you go to bed, the time you wake up, how many times you wake up during the night and how you feel in the morning.

  • Sleep tracking apps on your phone or smart device that can monitor your sleep patterns and provide insights into your sleep quality.

Improving your sleep hygiene can lead to more restful and restorative sleep. You can start by establishing a consistent sleep schedule. To regulate your body's internal clock, aim to go to bed and wake up at the same time each day — yes, even on weekends.

Calming activities like reading, meditating or taking a warm bath help signal your body to wind down and prepare for sleep. Avoid screen time close to bedtime, since the blue light emitted from electronic devices can suppress the production of melatonin, the hormone that helps you fall asleep.

Additionally, make sure your bedroom is conducive to sleep — a cool, dark and quiet environment can help you drift off more easily. If noise or light is an issue, consider using earplugs and an eye mask or blackout curtains. Sound machines or sleep headphones can also help mitigate environmental noises and create consistency in background noise.

Your bedding is just as important. Invest in a supportive and comfortable mattress, pillows and sheets that support your desired body temperature. If you're a warm sleeper, opt for cooling sheets, and if you're a cold sleeper, consider using flannel sheets or a memory foam mattress topper — memory foam is known to retain heat.

Just as nighttime rituals can help signal your body to prepare for sleep, a consistent diet and exercise routine can also help regulate your body's natural sleep/wake cycle. Avoid eating heavy meals or drinking caffeine close to bedtime, and try to incorporate regular exercise into your daily routine — aim for at least 30 minutes of physical activity per day.

Sleep requirements vary by age and personal factors, but most adults need 7-9 hours of sleep per night to function at their best. You may need more or less depending on your lifestyle and age. Listen to your body and prioritize getting enough rest each night.

While some individuals may function well on six hours of sleep, most adults need at least seven hours for optimal health. Consistently getting less than six hours of sleep per night can increase your risk of chronic sleep deprivation and the associated health risks — cardiovascular disease, obesity, mental health issues and accidents.

Neither option is ideal. While getting a minimal amount of sleep may help you function in the short term, consistently getting less than the recommended amount can have detrimental effects on your mental and physical health. Short-term sleep deprivation can affect your mood, decision-making skills and overall performance, while chronic sleep deprivation can lead to serious (possibly life-threatening) health issues. Consult a healthcare professional if you regularly get less than seven hours of sleep per night.

  • Shelby Harris, a licensed clinical psychologist specializing in behavioral sleep medicine and the director of sleep health at Sleepopolis

  • Greg Hammer, professor, physician, anesthesiologist and author at Stanford University School of Medicine

  • Jade Wu, Mattress Firm’s Sleep Health Expert, board-certified sleep medicine specialist and sleep researcher at Duke University School of Medicine

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