By Dr. Mercola
About 1 in 3 Americans are getting less than seven hours of sleep a night, and an estimated 83.6 million adults in the U.S. are sleep-deprived.1,2 If you're trying to lose weight, you may be surprised to know the amount and quality of sleep you get might be as influential as your choice of diet and exercise.
Research continues to confirm that sleep is an important factor in helping you avoid diabetes, heart disease, high blood pressure and obesity. Notably, sleeping in on weekends — a practice quite common among teenagers — may be more beneficial for adults than you may have imagined. In fact, it may not be simply what your body wants, but also precisely what it needs.
Weekend 'Catch Up Sleep' Shown to Decrease Body Mass Index
A study published in the journal Sleep3 involving 2,156 adults aged 19 to 82, indicates sleeping in longer on weekends — also known as "catch up sleep" (CUS) — may positively impact your weight.
On average, the group of participants who slept up to two hours longer on weekend days than weekdays had a significantly lower body mass index (BMI) than the non-CUS group. Researchers observed that every additional hour of weekend CUS was associated with a 0.12 decrease in BMI. Lead author Dr. Chang-Ho Yun, department of neurology, Seoul National University Bundang Hospital, told Reuters:4
"Short sleep … is a risk factor for obesity, hypertension and coronary heart disease, as well as mortality. If you cannot sleep sufficiently on workdays because of work or social obligations, try to sleep as much as possible on the weekend. It might alleviate the risk for obesity."
Yun cautioned that using weekend CUS while sleeping far below the optimal amount during the week would, at some point, result in diminished benefits. He also noted that sleeping in on weekends is preferable to napping because it is more likely a deeper sleep and follows your body's sleep-wake rhythms.5 Jean-Philippe Chaput, assistant professor, Healthy Active Living and Obesity Research Group, University of Ottawa, who was not involved in the study, commented:6
"Short sleepers tend to eat more meals per day, snack more, engage in more screen time and may be less likely to move due to increased sensations of fatigue when not rested."
If You Sleep Only 5 Hours a Night, You May Be at Risk for Obesity
A 2013 study7 published in the Proceedings of the National Academy of Sciences associated insufficient sleep with the risk of obesity. When the 16 adult participants received insufficient sleep, they tended to eat smaller breakfast meals and more snacks.
On average, when sleeping only five hours a night, the study subjects gained nearly 2 pounds (0.82 kg) a week. Notably, they consumed most of their extra calories at night after dinner. When participants received adequate sleep — about nine hours a night — they were able to maintain their weight, and tended to consume less high-carbohydrate and high-fats foods. Kenneth Wright, director of the Sleep and Chronobiology Laboratory at the University of Colorado Boulder and study author, said:8
"I don't think extra sleep by itself is going to lead to weight loss. Problems with weight gain and obesity are much more complex than that. But I think it could help. If we can incorporate healthy sleep into weight-loss and weight-maintenance programs, our findings suggest it may assist people to obtain a healthier weight."
The study also found men and women responded differently when presented with access to unrestricted amounts of food. Regardless of their amount of sleep, men gained some weight when they could eat as much as they wanted. Women, on the other hand, were able to successfully maintain their weight with adequate sleep regardless of the amount of food available. When allowed to sleep for only five hours, both genders gained weight.
Irregular Sleep Can Disrupt Your Body's Internal Clock
All of that said, preliminary results of a study9 presented at SLEEP 2017, the 31st annual meeting of the Associated Professional Sleep Societies in Boston, indicate that going to bed and waking up later on weekends than you do during the week is linked to poor health and mood problems, as well as fatigue and sleepiness. Lead author Sierra Forbush, a research assistant in the Sleep and Health Research Program at the University of Arizona, said:10
"These results indicate that sleep regularity, beyond sleep duration alone, plays a significant role in our health. This suggests that a regular sleep schedule may be an effective, relatively simple and inexpensive preventative treatment for heart disease, as well as many other health problems."
The research, which was composed of survey data from 984 adults aged 22 to 60 years, also revealed an 11 percent increase in heart disease risk for each hour of irregular sleep. A significant negative effect of being sleep-deprived is poor judgment, especially when it comes to assessing what lack of sleep is doing to you. In our fast-paced world, it seems that functioning on less and less sleep is considered to be admirable, a kind of "badge of honor."
The reality is that many people believe they are adapting to and functioning well with less sleep even though the reality is they are in a constant state of decline physically, mentally and emotionally. Says sleep expert Phil Gehrman of the behavioral sleep medicine program at the University of Pennsylvania's Perelman School of Medicine:11
"Studies show that over time, people who are getting six hours of sleep, instead of seven or eight, begin to feel that they've adapted to that sleep deprivation — they've gotten used to it. But if you look at how they actually do on tests of mental alertness and performance, they continue to go downhill. So there's a point in sleep deprivation when we lose touch with how impaired we are."
Exhaustion From Lack of Sleep Fuels Your 'Hunger Hormone'
One of the most bothersome effects of lack of consistent, high-quality sleep is the havoc it wreaks on two of your body's hunger-regulating hormones. Chronic lack of sleep can cause ghrelin — also known as your "hunger hormone" — to skyrocket, making you feel hungry when you don't really need to eat.
Ghrelin, it appears, may also act on your brain's pleasure centers, driving you to reach for another bowl of ice cream simply because you remember how good the first one tasted and made you feel while you were eating it. Late-night eating is of particular concern. If you are caught in a cycle of late-night eating, you are likely tempted to indulge in carbohydrate-rich snacks. As such, you can be certain that most of what you consume after your evening meal is going to be stored as fat.
For example, when you eat a sugary dessert your production of insulin increases so the sugar in your blood can be taken to your cells and used for energy. Eating this sugar increases your production of leptin, also referred to as the "obesity hormone." Leptin controls hunger and feelings of satiety. Because leptin is secreted by fat tissue, if you are overweight, you likely have higher than normal levels of leptin, which may lead to leptin resistance.
High leptin levels have been tied to heart disease, high blood pressure, obesity and stroke, as well as blood-sugar problems.12,13,14 If you are leptin resistant, your body will receive signals that may lead you to continue to eat even when you've actually had enough. Researchers involved with a sleep disorders study involving more than 1,000 participants, which sought to uncover a link between sleep problems and metabolic hormones, concluded:15
"Participants with short sleep had reduced leptin and elevated ghrelin. These differences in leptin and ghrelin are likely to increase appetite, possibly explaining the increased BMI observed with short sleep duration."
Those who slept for short durations had 14.9 percent higher ghrelin levels and 15.5 percent lower leptin levels than those who got adequate sleep.16
Give Up Late-Night Eating: Intermittent Fasting Is a Better Choice
As I have often mentioned, your body can be helped by periods of peak fasting, which is when you restrict your daily eating schedule to a specific window of time. Based on the experimenting I have done in recent years, I recommend a six- to eight-hour timeframe in which to consume your daily food intake. For example, if you skip breakfast and make lunch the first meal of your day, you might restrict your food intake to the hours of 11 a.m. to 6 p.m.
The key is to eat only within this narrow window of time, and to ensure you eat the last meal at least three hours before bedtime. This is a great way to help you commit to forego late-night eating. Fasting is important because when you eat multiple meals spread throughout the day, you rarely, if ever, empty your glycogen stores. It takes eight to 12 hours for your body to burn the sugar stored as glycogen.
By fasting about 14 to 16 hours a day, you will give your body more than enough time to drain glycogen stores and shift into fat-burning mode. Intermittent fasting will dramatically change the way your body processes food for fuel. You can learn more about how to balance your body's energy supply through fasting and fat-burning in my latest book "Fat for Fuel."
Seven Ways Poor Sleep Affects Your Body and What You Can Do About It
According to Authority Nutrition, consistently getting less sleep than your body needs brings about some or all of these effects:17
- Decreases your resting metabolism
- Diminishes your interest in physical activity
- Hampers your ability to fight cravings by increasing your appetite
- Increases your calorie intake, raising your risk for weight gain and obesity
- Increases your risk of insulin resistance
If you identify with even a few of these effects, it's time to make some changes to get back on track with your sleep. You can begin today by making even small adjustments to your daily routine and sleeping area. A few of my top recommendations are shown below.
- Address mental states that may interfere with sleep: Use the Emotional Freedom Techniques to help you deal with emotional or physical issues that may be disturbing your sleep
- Avoid alcohol, caffeine and other drugs, including nicotine: Be aware of the effects these habits, particularly if used daily and close to bedtime, may have on your sleep
- Develop a relaxing pre-sleep routine: Creating a consistent sleep ritual, which may include music, reading, stretching or taking a warm bath, will help cue your body that it is time for sleep
- Optimize your light exposure during the day, and minimize light exposure after sunset: Get at least 30 to 60 minutes of outdoor light exposure and minimize artificial light exposure at night; sleep in complete darkness
- Turn off the TV and other electronics at least one hour before going to bed: Electronic devices emit blue light, which tricks your brain into thinking it's still daytime and may interfere with your body's melatonin-secretion process
For additional guidance on how to improve your sleep, check out my "33 Secrets to a Good Night's Sleep."
Six Tips to Balance Your Sleep Needs
The National Sleep Foundation suggests the following tips to help you effectively support your body's need for quality sleep:18
- Vary your wake-up time on the weekends no more than an hour from your weekday schedule to better support a consistent sleep-wake schedule, also known as your body's circadian rhythm
- If need be, take a 20-to-30-minute nap on weekend afternoons, ideally between 2 p.m. and 3 p.m.
- Keep your naps on the shorter side to avoid feeling groggy or cranky afterward and prevent feeling too awake at bedtime
Women's Health recommends you also consider taking these additional actions to potentially help you sleep better:19
- Get some exercise: Cycling, running and swimming, as well as walking, can contribute to more consistent sleep
- Find out how much sleep your body needs: Use a wearable device to track and average your sleep as a means of determining your ideal rising and retiring hours, as well as create awareness of the actual amount of sleep you are getting
- Keep your bedroom cool: Because a lower body temperature helps you fall and stay asleep, set your thermostat on the cooler side year-round to promote quality sleep
My Recommendation: Get 8 Hours of Sleep a Night
Your main takeaway from this article should be the realization that sleep is vitally important to your health and, if you are like most adults, you probably need better sleep and more of it. Based on the available research, I recommend you set as your goal to consistently get right around eight hours of sleep a night. That recommendation is for adults only.
The sleep needs of seniors, young adults, teenagers and children vary, with most needing a bit more than eight hours. If you are not sure how much sleep you should be getting, review the sleep needs according to your age. Getting either too little or too much tends to be detrimental for health.
Remember, the recommended sleep time is the actual time you spend sleeping, not simply the number of hours you spend lying in bed. If you toss and turn a lot or have insomnia, there could be quite a gap between actual sleep and time in bed! To find out how many hours of sleep you're getting each night, try using a wearable fitness tracker with a sleep tracking function.