Seven Hours Is the Floor, Not the Goal

There is a particular kind of tired that has become normal. You wake to an alarm, drink coffee to get moving, hit a slump in the afternoon, and get a second wind around 10 p.m. that keeps you up scrolling. If that sounds like an ordinary week, you are in large company, and you are probably short on sleep.

The number

In 2015, the American Academy of Sleep Medicine and the Sleep Research Society¹ convened a panel of experts to review the research on sleep duration and health. Their consensus was that adults should sleep seven or more hours per night on a regular basis to promote optimal health. Sleeping less than that regularly was associated with weight gain and obesity, diabetes, high blood pressure, heart disease and stroke, depression, impaired immune function, more errors and accidents, and a higher risk of death.

The panel was careful with the word "more." Seven is the minimum. Some people need eight or a little more, particularly young adults, people recovering from sleep debt, and those who are ill.

The Centers for Disease Control and Prevention⁴ has long tracked how Americans measure up, and the picture is consistent. About a third of US adults report that they usually sleep less than seven hours.

What short sleep does to metabolism

One of the clearest demonstrations of how quickly sleep loss affects the body came from a small but influential study at the University of Chicago, published in The Lancet² in 1999. Healthy young men were restricted to four hours in bed for six nights. By the end of that week, their ability to clear glucose from the blood had dropped substantially, and their hormone profiles had shifted in ways that resembled those of much older people. Once they caught up on sleep, those changes reversed.

Four hours is extreme, and later studies used more realistic restrictions. But the pattern has held. Insufficient sleep worsens insulin sensitivity, increases appetite, and nudges people toward high-calorie foods. That is part of why sleep shows up in conversations about metabolic health and weight.

By the end of that week, their hormone profiles resembled those of much older people.

Insomnia is not just a bad night

Everyone has occasional nights of poor sleep. Chronic insomnia is defined differently. It means trouble falling asleep, staying asleep or waking too early at least three nights a week for three months or more, with daytime consequences.

For that condition, the American College of Physicians recommends³ cognitive behavioral therapy for insomnia, known as CBT-I, as the initial treatment for adults, ahead of sleeping pills. CBT-I is a structured program, usually four to eight sessions, that addresses the habits and thoughts that keep insomnia going.

Its core techniques can sound counterintuitive. Stimulus control means using the bed only for sleep and sex, and getting up if you are awake for a long time rather than lying there frustrated. Sleep restriction temporarily limits time in bed to the amount you are actually sleeping, which builds sleep pressure and consolidates rest, then gradually expands it. Cognitive work targets the anxious loops about sleep that make it harder to fall asleep. Trials show the benefits tend to last after the program ends, which is not true of most sleep medications.

CBT-I is available through trained clinicians, telehealth programs and some well-designed apps.

Rule out the hidden culprits

Some sleep problems are medical. Obstructive sleep apnea, in which the airway repeatedly collapses during sleep, is common and frequently missed, especially in women and in people who do not fit the stereotype. Loud snoring, pauses in breathing that a partner notices, morning headaches and persistent daytime sleepiness are reasons to ask about a sleep study. Untreated apnea is linked to high blood pressure and heart rhythm problems.

Menopause can also disrupt sleep through night sweats and hot flashes, and treating those symptoms often helps, which is one reason sleep comes up in discussions of menopausal hormone therapy. Low mood, chronic pain, restless legs, alcohol and some medications all interfere with sleep as well.

The habits that still matter

Basic sleep habits will not cure chronic insomnia on their own, but they support everything else. Keep a consistent wake time, including weekends, since a fixed wake time anchors the body clock more than a fixed bedtime. Get outdoor light in the morning, which is especially valuable in New England winters. Cut off caffeine by early afternoon. Be honest about alcohol, which helps people fall asleep and then fragments the second half of the night. Keep the bedroom cool, dark and quiet.

Regular exercise improves sleep quality, and better sleep makes it easier to exercise, a loop that also helps your aerobic fitness.

If you have tried the basics for a month and still struggle, bring it up at your next visit, and mention snoring or gasping at night if a partner has noticed it. Sleep apnea is common, underdiagnosed and treatable, and home sleep tests have made diagnosis far easier than it used to be. For chronic insomnia, cognitive behavioral therapy for insomnia, known as CBT-I, is the recommended first treatment over sleeping pills, and several versions are now available online.