Why getting A Good Night’s Sleep Is Still Important As We Age
You spend approximately one third of your life asleep, which may sound a little dull, but it’s entirely necessary. You see, the many years that you spend asleep throughout your lifetime ensure that you’re at your very best for the many years that you spend awake.
The Stages of Sleep
There are several stages of sleep that occur through the night – depending on the quality and length of your sleep. The first stage is a light sleep during which your eyes move slowly, and your muscles are still active. This stage of sleep only lasts around 10 minutes. During light sleep, you may also experience a ‘Hypnic Jerk’ where your muscles contract randomly and suddenly. Experts believe this happens because your brain misunderstands the sensation of muscles relaxing as you drift off to sleep. Your brain causes your muscles to tense, as it thinks that your body is falling, and wants to ‘catch’ you before you hit the floor.
During the second and third phases of the sleep cycle your eyes stop moving, your brain waves slow down, and your body temperature drops. With these stages, your blood pressure drops and your body releases human growth hormone (HGH) from your pituitary gland. HGH is essential in body repairs, including rebuilding micro tears that occur naturally in your muscles when you exercise. The more you sleep, the more time they have to repair and grow. The second sleep phase last around 20 minutes and the third lasts a bit longer.
This deep sleep stages are fourth and fifth. Stage four is referred to as delta sleep because the brain waves slow. This lasts around 30 minutes. Stage five is called rapid eye movement (REM) sleep. During REM, your body is more or less paralysed to allow maximum repair to your muscles and bones. Your brain, however, remains active, and you start to dream.
As we age, our sleep cycle alters, and we often spend more time in light sleep rather than in the deep sleep stages. This means that during the day we can often feel more tired.
Sleep Heals Your Body
Good quality sleep is essential for repairing your body. Not only does sleep deprivation prevent muscle repair and growth hormone from being released, it also increases levels of cortisol. Cortisol is the dreaded stress hormone that causes weight gain and suppresses your immune system. It’s not just your body that repairs during the night, your brain does too. Because deprivation of sleep leads to poor attention span, inability to learn or problem-solve, and a decrease in reaction time, sleep helps your mind work more efficiently.
Another benefit of adequate sleep is that it assists your metabolism to function normally. The hormone leptin decreases in the body when you haven’t slept properly. This hormone is essential for telling you to stop eating when you are full. So, you are more prone to overeating, and your metabolism is going to under-perform when you lack sleep.
Sleep deprivation and physical stress are able to trigger the immune system into action. As part of a study, 15 young men had eight hours sleep every day for one whole week, and then their white blood cells were categorized and measured. They then spent 29 hours without sleep, and their white blood cells were compared. During the time of sleep deprivations, granulocytes (white blood cells that play a role in immunity) increased in number, particularly at night. Usually these levels reduce during the night, which means that these cells were responding to the physical stress of sleep deprivation, mirroring the body’s response to stress.
Earlier studies had found a link between lack of sleep and the development of certain diseases and conditions, such as high blood pressure, diabetes and obesity, meaning that adequate sleep has been shown to help keep the immune system working properly.
How Do I Get to Sleep?
Sleep itself is straightforward; the difficult part, sometimes, is getting into that state. Many things tell us that it’s time to sleep. Obviously, the longer we stay awake, the sleepier we become: this is called homeostatic regulation. Usually, we are awake for 16 hours or so before we get sleepy.
Another regulator of sleep is our body clock (circadian rhythm), which links sleep with other bodily cycles, such as temperature, growth and levels of various brain chemicals, including serotonin, cortisol and melatonin.
These two basic instincts can be used to our advantage when we are trying to send ourselves to sleep. Getting strong homeostatic sleepiness means going to sleep no earlier than 15 to 19 hours after waking up. Optimizing circadian sleepiness means going to sleep when we start to feel drowsy in the evening – neither earlier nor later.
Our clock is usually timed so that we fall asleep around 11pm and wake up at 7am. Some of us (often referred to as ‘night-owls’) have later-timed body clocks and may not be ready to fall asleep until around 2am, preferring to sleep until 10am. Others (the ‘larks’) have early-timed body clocks and can fall asleep quickly in the evening – often by 9pm – but then wake early.
As we age, we can find it harder to fall asleep, sometimes feeling sleepier earlier in the evening and then waking very early in the morning. Known as advanced sleep phase syndrome, this still provides the regular sleep duration (such as eight hours), but instead, the sleeping time is shifted forward.
Staying Asleep
Insomnia can often be common as we age. Stressful lifestyles, working patterns and physical changes in the body can contribute to insomnia. If you suffer with insomnia regularly, you should visit your doctor, as there are often medical reasons such as diabetes or even medications that can cause insomnia.
Declining hormone levels associated with the menopause, as well as hot flushes and alterations in breathing can also contribute to insomnia for many women. Making lifestyle modifications such as reducing caffeine consumption, and maintaining a regular sleep-wake schedule can sometimes help to alleviate insomnia.
How Do I Wake Up?
Unless we use alarm clocks, the timing of our waking is determined primarily by circadian rhythms, so even if ‘larks’ are sleep-deprived, they are unlikely to sleep in. These different timed body clocks do not pose a problem. However, sleeping ‘out of sync’ with our body clocks, even if we have been awake for a long time and feel sleepy, is relatively inefficient. Trying to fall asleep too early, in relation to our natural rhythms, is simply ineffective.
An example of how this works is seen when daylight and darkness patterns fail to gel with our body rhythms. This is generally experienced as jet-lag, but is also seen in shift workers and following even small changes in our circadian rhythm, such as at the beginning or end of daylight savings periods. This mistiming can make it difficult for us to fall asleep or wake at the right time for a number of days.
How to Re-set Your Body Clock
We can usually reset (entrain) our body clocks each day by means of cues such as light, noise and activity. For example, a dark, quiet room helps to promote sleep. Taking a hot bath, shower or sauna in the late evening sometimes helps us to fall asleep, as our temperatures tend to drop post-bathing, so our bodies think it must be ‘sleep time’.
By contrast, exposure to bright fluorescent light in bathrooms, or emanating from computer screens or televisions, will prevent sleep. Another way to synchronize our body clocks is to expose our bodies to bright light, which is usually obtainable for free, without a prescription. For those troubled with early-morning waking, exposing ourselves to bright natural light in the evening can delay our body clock by a few hours. Equally, delay in getting to sleep can sometimes be helped by getting some bright morning light to bring the clock forward. Setting a lamp to switch on five minutes before waking up (particularly in winter) is an easy way to do this.
For those who need to reset mistiming body clocks, melatonin is available on prescription. This is designed as short-term therapy and most preparations contain large amounts of melatonin (1-3mg), usually several times more than are our bodies’ normal circadian rhythms in order to clonk us back into cycle. The melatonin available over the counter in many pharmacies contains little active ingredient and is usually ineffective at correcting insomnia (although it may have antioxidant benefits).
Last Reviewed 11/Mar/2014
