It’s winter. In most parts of the nation, people have already begun to hunker down as the temperatures continue to drop. For many, even during long, cold winter nights that seem best for hibernation, quality sleep can feel far out of reach.
Since the 1930s, we’ve known that sleep is much more complex than it appears. It occurs in several discrete stages, each of which plays a role in maintaining health, growth and functionality. Here are the different kinds of sleep:
- What’s known as “quiet sleep,” where we become drowsy, body temperature drops, muscles relax, and breathing slows down.
- Deep or slow-wave sleep, which is important for repair and renewal; this is the kind of sleep that yields large pulses in growth hormone, which builds muscle and repairs damage.
- REM (Rapid Eye Movement) sleep, where the brain is highly active and dreaming. Body temperature, blood pressure, heart rate and breathing rate speed up to daytime levels. Adequate REM sleep is vital for daytime learning and memory.
As we age, the length of time spent asleep can decrease, but shifts also occur in the amount of time spent in each sleep stage. This can impact both short-term and long-term health.
Young adults spend about half their total sleep in stage 2 (deep) sleep and about 20% of their time in REM sleep. By the time we are 65, some of us won’t experience much slow-wave sleep, if any; REM sleep is also reduced as we age.
If high-quality deep sleep can be maintained or restored, at least some of the impact of lack of sleep on the aging process could be slowed or perhaps even reversed. If there’s a single best-chance fix for loss of quality sleep with aging, it’s fitting sleep patterns more closely to patterns of light and dark. This becomes especially important when seasons change, as they are right now.
Humans are not nocturnal. They are designed to get sleepy and slumber when it’s dark, and to be awake, alert and active when the sun is up. When we refuse to obey this ancient aspect of our physiology things go wrong in our bodies. The key here is believed to be a neurohormone called melatonin. Melatonin is produced in the pineal gland, which is located deep between the hemispheres of the brain. When darkness falls, melatonin is produced. It promotes deep sleep and has powerful antioxidant effects. Both REM and slow-wave sleep are reduced when melatonin production falls.
Light at night is linked strongly with daytime fatigue and disrupted sleep, but also with more concerning issues like a 60% increase in risk of breast cancer in women who engage in shift work (flight attendants, nurses, etc.).
[Rats raised in cages where lights are left on for much of the night have higher cancer rates, but when they received shots of melatonin to replace what they were not producing because of constant light, their cancer rates fell back to baseline. When Israeli researchers took a map showing areas of the world with more light at night (LAN) and laid it over another map showing the parts of the world with the most breast cancer, they found a high correlation between these two factors. The evidence here is so compelling that the World Health Organization deemed shift work a “probable carcinogen”.]
Am I suggesting you go to bed when night falls, even if it’s 6:00 pmor earlier? Yes and no. Yes, sticking with the natural rhythm of light and dark means going to bed soon after darkness falls, abstaining from bright light inside and out when bedtime is near, and not exercising late at night. And no, adhering to a strict regimen of “sleep when it’s dark, awake when it’s light” isn’t possible for most of us living in the modern world. Still, even small steps in the direction of less light at night will help promote melatonin production and increase slow-wave and REM sleep quantity and quality. This may mean enhanced nighttime surges of growth hormone and retention of learning and memory ability, courtesy of improved REM sleep.
Here’s some things to keep in mind before your head hits the pillow:
- Keep lights dim in the evenings.
- Avoid looking at LED screens within an hour or two of bedtime—that includes phones, tablets, computers and TVs.
- Try curling up with a good book, playing a board game or cards, or enjoying conversation instead.
- Keep your bedroom as dark as possible; even the light from a digital clock is enough to cause melatonin production to fall. (If streetlights or car headlights are an issue, invest in blackout curtains.)
- Start rising with the sun: as soon as dawn comes, open the curtains and flip on lights.
How about supplemental melatonin? So far, it appears that occasionally taking this neurohormone near or at bedtime is an effective way to aid sleep. We don’t know, however, whether daily use is safe. A recent story on the Dr. Oz show covered this topic—apparently, many people are ill-advised to take melatonin nightly as a sleeping pill, and pop multiple tablets to try to get back to sleep when they wake in the middle of the night. This is having a negative impact on their sleep quality and their ability to get up in the mornings.
If you are taking melatonin, don’t take more than the dose recommended on the container if it doesn’t work to help you sleep; don’t take it in the middle of the night; and don’t take it every day. It’s always better to promote the body’s own production of a hormone where possible than to add it from an external source.
An interesting research study that supports Ageology’s standard dietary advice: going to bed with low blood sugar helps stimulate the nocturnal surge in growth hormone. Eating carb-rich food right before bed might help make you sleepy, but it will reduce that valuable growth hormone surge. While you adjust your sleep schedule, consider eating low-carb food and abstaining from food within the few hours before bedtime.