High-quality sleep is getting scarcer and scarcer these days thanks to ever-increasing obesity rates, work hours, TV watching, video game playing, and other distractions that keep us up at night.
To research average sleep habits, the CDC followed 74,751 adults in 12 states. According to the findings published in 2011, 35.3% of people reported less than 7 hours of sleep per night, 38% reported unintentionally falling asleep during the day at least once in the preceding month, and 4.7% reported nodding off or falling asleep while driving at least once in the preceding month.
Sleep insufficiency has been linked to auto crashes, industrial disasters, and medical and other occupational errors. It can also increase risk of chronic diseases like hypertension, diabetes, depression, obesity, and cancer; increase mortality; and reduce quality of life and productivity.
When your body is asleep, it might look inactive, but that’s far from the case. It’s very busy repairing tissue and producing hormones—functions that are especially important if you’re subjecting your body to increased levels of stress every day through exercise.
So, let’s look at some of the various effects sleep has on our ability to achieve our health and fitness goals, and what we can do to improve the quality of our sleep.
A large amount of fat loss occurs while you sleep for two reasons.
Your body burns quite a few calories while you sleep (a 160-lb. person burns about 70 calories per hour), and much of it must come from fat stores because you haven’t eaten any food in several hours. Furthermore, much of your body’s growth hormone is produced while you’re sleeping, further stimulating fat loss.
With that in mind, it’s not surprising that the amount we sleep affects our weight-loss efforts and overall health.
In a study conducted by the University of Chicago, 10 overweight adults followed a weight-loss diet (caloric restriction) for 2 weeks. One group slept 8.5 hours per night; the other, 5.5. The 5.5-hour group lost 55% less fat and 60% more muscle than the 8.5-hour group, and on top of that, they experienced increased hunger throughout the day.
This correlation has been observed elsewhere as well. Research conducted by the National Center for Global Health and Medicine associated shorter sleep duration with increased levels of body fat. There’s also evidence that acute sleep loss causes insulin resistance to a level similar to someone with type 2 diabetes, which can increase the rate at which your body stores carbohydrates as fat.
Insufficient sleep can negatively impact our hormone profiles.
Another study conducted by the University of Chicago found that when 10 healthy men reduced sleep for a week from about 9 hours per night to 5, their testosterone levels dropped by up to 14% during the day.
It’s also known that insufficient sleep decreases growth hormone and insulin-like growth factor-I (IGF-1) levels, which play important roles in maintaining muscle mass.
While you would think that sleep deprivation has profound effects on strength and speed, research says otherwise.
A study conducted by the Imam Khomeini International University demonstrated that one night of sleep deprivation didn’t affect anaerobic power in male participants, but did impair reaction times.
A study conducted by the Defence and Civil Institute of Environmental Medicine had 11 male subjects undergo 60 hours of sleep deprivation and then perform repetitions of forearm and leg exercises. They found that the sleep-deprived group performed equally as well as the group that slept 7 hours per night in reaction time and muscular performance.
Further research by the same institute, however, found that sleep deprivation does negatively affect time to exhaustion (subjects couldn’t exercise as long before feeling exhausted) and perceived exertion (the workouts felt harder).
A practical takeaway from these findings is that you don’t have to skip your workout if you slept less than usual, but in general, try to get a good night’s sleep as frequently as you can.
My experience lines up with the above findings: Sleep-deprived workouts are tough to get through, and while I often lose a rep or two (reduced muscle endurance), my strength isn’t negatively affected.
Now, while sleep deprivation doesn’t necessarily impair athletic performance, studies indicate that extended sleep may improve it. Research conducted by Stanford University demonstrated that when basketball players extended sleep from 6–9 hours per night to at least 10 hours per night, they ran faster, shot more accurately, had better reaction times, and felt more physically and mentally fit during practices and games.
Sleep needs vary from individual to individual, but according to the National Sleep Foundation, adults need 7–9 hours of sleep per night to avoid the negative effects of sleep deprivation.
Since genetics and age affect how much sleep your body optimally needs, a simple way to determine what’s optimal for you is to pick a two-week period such as a vacation and go to bed at the same time each night without an alarm set.
Chances are you’ll sleep longer than usual at first if you have “sleep debt” to cancel out, but toward the end of the second week, your body will establish a pattern of sleeping about the same amount every night. And it’s trying to tell you something: That’s exactly how much sleep it needs.
Most people know they should sleep 7–9 hours, but it’s easier said than done. As of 2006, it’s estimated that 50–70 million Americans suffer from a sleep disorder.
Hypnotic drugs like Ambien, Rozerem, and Sepracor are common solutions, but they have been associated with a host of rather scary side effects, including:
Relying on these types of drugs is clearly not ideal. Fortunately, there are quite a few things you can do to naturally improve your sleep:
There are also several natural supplements you can take to sleep better.
Melatonin, a hormone that induces sleep, is sold as a dietary supplement. Research has shown that supplementation with melatonin can help you fall asleep faster, and sleep better.
The common clinical supplementation protocol used is 3-6 mg 30 minutes before bed.
GABA, also known as gamma-aminobutyric acid, is an amino acid that helps stimulate relaxation and sleep. Research has shown that low brain levels of GABA causes increased wakings after falling asleep, and that supplementation with GABA can induce relaxation, and help you fall asleep faster, stay asleep longer, and improve the quality of your sleep.
The common clinical supplementation protocol used is 500-600 mg before going to bed.