Sleeping is so much more than just rejuvenation

Photo credit: Cristina Jiménez Ledesma on Visualhunt / CC BY-NC-ND

What happens when you don’t get a good night’s sleep? You’re grumpy and tired the next day. Energy restoration is an obvious benefit of a good sleep. Yet, sleeping has many other positives.

First, sleeping helps us commit things you learn during the day to long-term memory. Things you learn during the day are only parked in memory for short-term safekeeping. These tidbits of information are later processed and consolidated during sleep to commit to longer term memory.

Second, while you sleep, waste excreted by your brain cells is collected, and then eventually disposed of in your urine. Sleep is essentially the brain’s sanitary department. Sleep deprivation results in toxic waste accumulation in the brain, thereby negatively impacting your cognitive ability.

Sleep physiology

Photo credit: Tuomas A. Lehtinen Photography on VisualHunt / CC BY-NC-ND

Before I look into the sleep challenges of older adults, I need to explain the physiology of sleep. Sleeping is not a single linear thing you do, in contrast, you cycle, from sleep onset, through 4 intermediate stages to eventual wake-up.

The first 3 stages comprise NREM (Non-Rapid-Eye-Movement) sleep. Individually, they are referred to as NREM stages 1, 2, and 3. The fourth stage of the sleep cycle is known as the REM (Rapid Eye Movement) stage. As its name suggests, your eyes move in all directions during REM sleep. After REM, you cycle back to stage 1 NREM.

As you progress from stage 1 to 2, then 3, you descend from a light sleep to an increasingly deeper one. Both your heart rate and body temperature gradually drop. When you reach stage 3, you are in a deep sleep, and awakening is relatively more difficult.

Physical restoration is one of the major benefits of being in stage 3 sleep. This is like spa time when your body de-stresses and repairs are done. You wake up feeling rejuvenated the next day.

Stage 3 NREM is required to reap the aforementioned cognitive benefits of sleeping. Memory consolidation and toxin removal happen then.

Does it all sound complicated? To deal with the complexity, your brain has an internal clock located inches behind your eyes, known as the suprachiasmatic nucleus (SCN), which regulates sleep in a 24-hour rhythm (aka the circadian rhythm). As the supreme sleep commander, the SCN does not do much itself, but communicates its directives to other brain regions, for instance, to generate hormones such as cortisol (for stimulation) and melatonin (for drowsiness), and to modulate body temperature.

The SCN is largely self-synchronizing, but it takes certain external cues such as light/darkness to fine-tune the circadian rhythm.

Effects of aging

When the SCN is doing its job, you fall asleep at night and sail smoothly from stage 1 to 2 to 3 where cognitive reset and physical restoration transpire, then to REM and back up to stage 1, and so the cycle repeats. However, when you age, the SCN loses some of its effectiveness, ending up with their electrical signals being crossed, causing sleep to fragment. Specifically, an older adult may descend like before, from stage 1 to stage 2, but instead of progressing to deep sleep, they circle back to stage 1 to restart the descent. The net result is that, for older folks, time spent in deep sleep and REM is reduced.

Recall that cognitive reset happens in deep sleep. Less time in deep sleep entails less memory consolidation and less toxin removal, negatively affecting cognitive abilities.

Practical tips

A national American health survey conducted over the years 2005-2010 revealed that about 4% of adults aged 20+ used prescription sleeping pills in the past month. Also, such use increased with age, ranging from 2% for those aged 20–39, to 6% for those aged 50–59, and finally to 7% among those aged 80+.

First and foremost, prescription sleeping pills should only be taken with the recommendation of a physician and for a short time only. Sleeping pills are hypnotics: chemical agents that induce drowsiness. In other words, it helps you fall in sleep faster, and keep you there longer. But, not all sleep stages are created equal. Sleeping pills put you into light sleep faster at the cost of upsetting the delicate chemical balance in your brain and making it even harder to go into deep sleep.

So, what to do? Below, I list 5 lifestyle adjustments that you can make to improve your sleep without resorting to taking medication.

1. No alcohol, caffeine, nicotine

Alcohol, caffeine, and nicotine are substances that temper the chemical balances in your brain and consequently the circadian rhythm.

Some people actually take a nightcap, i.e., a small alcohol drink just before bedtime, to help them go to sleep. Does that really work? Yes, and no.

Like a sleeping pill, alcohol puts you to sleep faster because it induces drowsiness. But its secondary effect is one of stimulation, especially in the later hours of sleep, causing you to spend less time in deep sleep and REM. Alcohol induces sleep but does not give you the quality restorative sleep with all its associated cognitive and physical benefits.

My manager used to say coffee is the most cost-effective productivity aid, and that is why our office had always provided free coffee to its staff all day long. Caffeine may well be the best productivity aid ever, but sleeping aid it is definitely not. Boomers should stop caffeine consumption 4 to 6 hours before bedtime.

Like caffeine, nicotine is a stimulant. Its negative consequences are well documented and are much worse than just not getting a good night’s sleep. Use of nicotine is to be avoided at all time.

2. LED screens

Electronic devices—smart phones, laptops, tablets, e-readers, flat-screen TVs, etc—permeate our home life. These devices have in common a LED screen that emits a blue light. Blue light is part of the visible light spectrum, with sunlight being its biggest natural source. Enough exposure to blue light at night can trick the brain into thinking that it is still daytime, leading to the suppression of the production of the sleep hormone melatonin in favor of the production of the steroid hormone cortisol, therefore upsetting the circadian rhythm.

To have a better night’s sleep, turn off your mobile phone well before you go to bed. For me, I shut down my computer, and turn to a book for some easy reading just before bedtime.

3. Keep cool and sleep through

Your body temperature drops as you descend into deep sleep. A very warm bedroom makes it harder for the descent. An ideal room temperature for a good night’s sleep is 65°F (18°C). The exact temperature threshold may be adjusted according to individual differences.

4. Exercise early

Physical activity is universally accepted as a prerequisite for good health, regardless of age. Exercising increases the heart rate, raises the body temperature, and boosts levels of adrenaline and cortisol which make you feel good afterwards. Those are all good unless you are trying to fall asleep shortly after exercising, in which case your body needs to go the opposite direction.

The advice is to exercise early in the day, if possible. A modern lifestyle often limits the hours we can exercise. If you can only exercise in the evening, it is not ideal for sleeping purposes, but it is still better than not exercising at all. Make sure that you leave enough time for your body to cool down before going to sleep.

5. Social interaction

A sweet friendship refreshes the soul.

(Old Testament proverb, ‘The Message’ Bible)

A sweet friendship not only refreshes the soul but also enhances the sleep. What better way to prevent or combat depression, a sleep inhibitor, than with a warm get-together with friends. Whether social media connection has the same effect as face-to-face interaction is debatable, but why not both? Like all stimulants in this list, meet up earlier in the day to allow your brain to calm down before bedtime.

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