I have had quite a few questions from members about last week’s article on sleep, so thought I would answer them this week. Many questions related to whether it mattered if sleep length varied. My first comment then is that the sleep duration quoted in trials and so on are averages. We will all have spells where we sleep less well, and that is fine. It is the average over a long period that is more important. When we are under stress we sleep less well: if we have work deadlines or family worries for example. This is normal and will affect us all at one time or another. There will also be outliers. Margaret Thatcher famously survived on only 4 hours sleep per night. I guess whether that was good or bad is a matter of opinion!
What about naps?
Well, the science tells us that naps are neither good or bad for you, but are highly individual. Some people will do well to nap, others not. However, if napping, be sure not to go on too long. The reason we sleep from a biological perspective is that levels of the neuro-transmitter (a chemical which circulates in our nerves and communicates with our brains) acetylcholine build up during the day to the point that they signal it is time to sleep. If we nap, the levels of acetylcholine reduce (think of a tap being opened), such that they will be lower than they should be later in the day and not signal to use appropriately when to sleep. I personally almost never nap, and if I do, I take it as a sure sign that I need to address exhaustion, and ensure I get enough quality sleep over the next few days.
What happens when we sleep?
The first part of sleep is called non-REM (rapid eye movement) sleep, and has 3 stages. The first two are light, and typically last up to 25 minutes. Beyond this, you go into a deep sleep stage, and if woken will likely feel groggy and disorientated (another reason not to have a long nap). REM sleep follows, typically for about 90 minutes, during which you are paralysed. Yes you read that correctly. It makes sense though, as this is when we dream. Imagine the trouble you could get into if your body was able to move when it thought it was being chased by a lion in a dream…
The whole process then repeats itself. I occasionally use the sleep tracker on my watch to get an idea of how long I spend in the different sleep stages. However, if I’m honest I’m not sure how accurate my particular app is, and even so, I’m not sure I can alter them, and don’t want to worry myself if I’m not getting ‘perfect sleep metrics’ when I review them the next day. I think it’s best if I simply adhere to good sleep hygiene (see below).
What about interruptions?
How detrimental are sleep interruptions? Well, it depends what those interruptions are. There is good data to show that chronic night shift workers are at increased risk of heart attacks and strokes, but bathroom breaks in the middle of the night which are sadly common for many of us do not cause a problem on the whole as you can get off again easily afterwards. This sounds silly and simple, but altering the time you last consume fluid before bed can make a huge difference to night-time bathroom breaks!
Sleep supplements
There are a number available, but by and large there is little scientific data to support their use. In part this is because of the difficulty performing quality human studies using supplements (compared to prescription drugs). They are not regulated in the same way, and there is also an issue regarding being sure what is actually in them, particularly when purchased online. Many sleep inducers are sedatives, and in some cases this has the potential to be addictive, with other side effects such as day-time drowsiness. Often supplements are plant-based derivatives, but the amount of active ingredient can vary, as can an individual’s tolerance to the compound.
Melatonin is one of the best known sleep supplements, and has been extensively studied. Many jet-lag remedies include this as an active ingredient and are popular worldwide. However, melatonin levels can be optimised without taking a supplement: adequate darkness at night, reduced artificial or blue light at night, adequate dietary protein and anti-oxidant consumption, a diet rich in lutein (eg kale, spinach, broccoli, corn…) will all increase natural levels of melatonin and should definitely be optimised before thinking about supplementation.
Other compounds which have been studies include Magnesium L-Threonate, L-Theanine, Apigenin and Myo-Inositol. L-theanine is found in green tea, and helps reduce anxiety as part of the reason for its use as a sleep aid. Apigenin is a polyphenol found in chamomile, and has reported benefits in sleep as well as other conditions such as diabetes and Alzheimer’s. Myo-Inositol has been shown beneficial in sleep quality in pregnant women. My advice would always be to seek individual advice from your healthcare professional in the first instance.
What about sex?
Often a sensitive topic, but one that we should not shy away from discussing. Interestingly this has indeed been shown to increase levels of sleep hormones within the body. Sex promotes sleep, but also sleep promotes sex: one study showed an additional hour of sleep increased women’s appetite for sex by 14%.
The more I’ve read and learned about sleep, the more convinced I am that it forms a key pillar of health, and something that we should be going out of our way to improve. I’ve started asking about my patient’s sleep more in my consultations, and it’s often amazing where that conversation takes us. It can be highly relevant to their cardiac symptoms!
My top tips to improve sleep:
- Avoiding light and in particular screens for at least an hour before bedtime
- Avoid drinking in the 2 hours before bedtime
- Avoid eating in the 3 hours before bedtime (Think 3-2-1)
- Getting 20 minutes of natural sunlight into your eyes within an hour of waking (even on a cloudy day, light levels (called LUX) are far higher outside than in). I try and do this every day if possible. For example, I’ve stopped wearing sunglasses when i’m cycling to work. I also use a super-bright seasonal affective disorder lamp in my office at Bournemouth Hospital – it is an interior room with no windows, so I get very little natural light otherwise on a weekday.
- Having a bedtime routine, and I would particularly encourage meditation – I do this for 10 minutes every night
- Keeping the room cool
- If you can’t sleep, get up and move away from the bedroom, read a book until you are ready again
- Avoiding alcohol and smoking
- Avoiding caffeine for at least 8 hours before bedtime – I very rarely consume coffee after lunchtime
- Exercise (but ideally avoid too close to bedtime, I’ve certainly had some poor nights sleep having done a workout late in the evening)
This long blog (and believe me, I could have gone on longer!!) I think only serves to highlight how important sleep is for us, and all aspects of our health. Pay attention to it, and I guarantee you will feel better for it.