From healthcentral.com
Too much—or too little—shuteye can lead to serious health problems. Here’s what the experts say about how much sleep adults really need
When it comes to how many hours of shuteye you get on average, the common recommendation for most adults is to clock at least seven hours each night, and that’s a solid general guideline, says Alex Dimitriu, M.D., a sleep medicine specialist and the founder of Menlo Park Psychiatry & Sleep Medicine in California.
However, it’s helpful to keep in mind that sleep duration can fluctuate based on things like age, lifestyle, illness recovery, pregnancy, or even existing underlying health conditions that you may, or you may not be, aware of.
“For most adults, seven hours is the minimum needed to function well, with nine hours as the maximum, but individual needs can vary quite a bit,” Dr. Dimitriu notes.
The most important thing to understand about sleep? Getting too few—or too many—ZZZs is strongly correlated with potential health issues, he notes. Frequently falling outside the seven-to-nine hour per night sleep window may not always be the cause of those problems, he adds, but can sometimes be an indication that something deeper may be going on. With that in mind, are you getting enough shuteye? Too much? We unpack what the science shows so you can rest easy.
Sleeping Seven to Nine Hours Is the Sweet Spot
Although your individual sleep needs may vary within the seven-to-nine hour timeframe recommendation, there is ample evidence that regularly sleeping less, and also sleeping more, may be detrimental to health, agrees Evin Jerkins, D.O., a sleep medicine specialist at Fairfield Healthcare in Lancaster, OH.
“At this point, there’s a large amount of evidence suggesting sleeping less than six hours a night leads to a higher risk of hypertension, type 2 diabetes [T2D], obesity, coronary artery disease, and stroke,” he explains. Regular shortened sleep can also have effects on mental health and is linked to higher risk of anxiety, depression, and problems with emotional regulation, according to 2025 research published in the American Journal of Lifestyle Medicine.
Consistently sleeping too little health risks because the body and brain go through crucial restorative processes during sleep phases, says Dr. Jerkins. For example, you'll experience higher levels of cortisol—the “fight or flight” hormone—without enough sleep, which can then elevate blood pressure and inflammation in the body. Sleep also plays a key role in brain health, since it's the time when new pathways are formed, waste is cleared, and memory is consolidated.
Regularly oversleeping, on the other hand, which is defined as getting more than nine hours of sleep per night, is also potentially harmful to your health. Took much shuteye is associated with the very same risks—including heart disease and T2D—that is seen with sleeping too little, per Johns Hopkins Medicine.
But, if not enough sleep is wreaking havoc on your body and mental health, wouldn’t “catching up” on your ZZZs be a good thing? Not so fast. Sleeping nine-plus hours per night can disrupt the body’s natural circadian rhythm, which in turn has been linked to higher inflammation and changes to metabolism. Also known as your body clock, your circadian rhythm regulates numerous physiological processes, including your immune response and brain function, according to research in Frontiers in Cellular and Infection Microbiology. When inflammation rises due to this rhythm being thrown off, it can affect how well your immune system works, proper hormone regulation, and your ability to stay alert all day.
“While there is no magic number for sleep … seven to eight hours is the sweet spot for most healthy adults,” Dr. Jerkins confirms. “If you’re consistently getting too few or too many hours of sleep, that doesn’t necessarily mean you have a health issue that leads to sleep disruption or insomnia. But it's important to see your doctor to rule out a serious condition that may be affecting your sleep,” he advises.
Sleep Needs Can Change With Age
A major variable in sleep needs is age, says Dr. Dimitriu. Older adults need the same amount of sleep as younger people but often get less total sleep at night, he explains. This can be due to several factors, such as:
Chronic illness. Numerous age-related diseases can cause both sleep disruptions or chronic fatigue, including arthritis, osteoporosis, and Alzheimer's disease.
Menopause-related hormone changes. Night sweats from oestrogen loss can disrupt sleep.
Side effects of certain medications. Older adults tend to be on a higher number of medications, and some common drugs can disrupt sleep including beta-blockers, antidepressants, inhaled asthma drugs, and diuretics that are used to manage blood pressure.
Sleep disorders. Insomnia, sleep apnoea, and movement issues such as restless legs syndrome are more common as people age, per the National Institute of Aging.
Yet, while many things can disturb sleep as we grow older, clocking those seven to nine hours may be more important than ever. According to the National Institute on Aging, lack of quality sleep can lead to problems with memory, increased risk of falls or accidents, and more stress overall. Research suggests that not sleeping enough, even in middle age, can raise risk of developing dementia later in life.
Because of the importance of quality sleep, it may be necessary to augment night-time sleep with daytime napping, advises Dr. Jerkins, even if that means getting seven to nine hours of sleep within a 24-hour period if you are 65 or older, rather than aiming for that amount in one block overnight. Just be sure to stay within that seven-to-nine hour range, rather than getting too much sleep due to long naps. Also, nap in the late morning rather than late afternoon, so you don't sabotage your bedtime later, he suggests.
Some People Just Need More Sleep
There are some situations where more sleep is necessary, says Dr. Dimitriu. However, those tend to be short-term needs that affect people who are recovering from, or living with, some type of injury or condition. They include:
Athletes. People who physically push their bodies may need longer recovery time from a major training session or race.
Chronic community. People with chronic disorders, including autoimmune diseases and cancer, may require more sleep each night.
People who are healing. Bouncing back from illness or injury may up your need for additional ZZZs.
Pregnant women. Research suggests that pregnancy is also a time for more sleep, but paradoxically, pregnancy can be rife with significant sleep disturbances due to nausea, heartburn, and back pain. Much like older adults, napping can help add to the total amount of hours for sleep in a 24-hour period.
Those with mental health conditions. This may include people with depression or bipolar disorder, who need more sleep to improve cognitive function, Dr. Dimitriu says.
Signs You're Not Getting Enough Sleep
If you’re regularly getting a minimum of seven hours of sleep, and you wake up feeling rested, especially without using an alarm, and you have consistent energy throughout the day, then it's likely you’re hitting your target when it comes to sleep amount, says Dr. Jerkins. Signs that you may need to increase your amount can include:
Daytime sleepiness
Difficulty focusing or paying attention
Emotional regulation problems, such as irritability or anxiety
Falling asleep very quickly
Food cravings, especially for carb-filled snacks
Hard time waking up in the morning
Increased clumsiness
Memory issues, including forgetfulness
More prone to catching common infections, such as cold or flu
Needing an energy boost like caffeine or sugar to get through the day
Slower reaction time
“Keep in mind that duration of sleep alone is not the only factor here,” Dr. Jerkins adds. “Quality sleep is also crucial. A good first step for both of those is going to bed and waking up at the same time on weekdays and weekends, to establish a consistent sleep schedule.”
https://www.healthcentral.com/sleep/is-seven-hours-of-sleep-enough
