Showing posts with label Sleep. Show all posts
Showing posts with label Sleep. Show all posts

Wednesday, 11 December 2013

10 Simple Things You Can Do Today That Will Make You Happier, Backed By Science



Happiness is so interesting, because we all have different ideas about what it is and how to get it. 
I would love to be happier, as I’m sure most people would, so I thought it would be interesting to find some ways to become a happier person that are actually backed up by science. Here are ten of the best ones I found.
1. Exercise more – 7 minutes might be enough

You might have seen some talk recently about the scientific 7 minute workout mentioned in The New York Times. So if you thought exercise was something you didn’t have time for, maybe you can fit it in after all.
Exercise has such a profound effect on our happiness and well-being that it’s actually been proven to be an effective strategy for overcoming depression. In a study cited in Shawn Achor’s book, The Happiness Advantage, three groups of patients treated their depression with either medication, exercise, or a combination of the two. The results of this study really surprised me. Although all three groups experienced similar improvements in their happiness levels to begin with, the follow up assessments proved to be radically different:
The groups were then tested six months later to assess their relapse rate. Of those who had taken the medication alone, 38 percent had slipped back into depression. Those in the combination group were doing only slightly better, with a 31 percent relapse rate. The biggest shock, though, came from the exercise group: Their relapse rate was only 9 percent!

You don’t have to be depressed to gain benefit from exercise, though. It can help you to relax, increase your brain power and even improve your body image, even if you don’t lose any weight.
A study in the Journal of Health Psychology found that people who exercised felt better about their bodies, even when they saw no physical changes:
Body weight, shape and body image were assessed in 16 males and 18 females before and after both 6 × 40 mins exercise and 6 × 40 mins reading. Over both conditions, body weight and shape did not change. Various aspects of body image, however, improved after exercise compared to before.
We’ve explored exercise in depth before, and looked at what it does to our brains, such as releasing proteins and endorphins that make us feel happier, as you can see in the image below.

2. Sleep more – you’ll be less sensitive to negative emotions

We know that sleep helps our bodies to recover from the day and repair themselves, and that it helps us focus and be more productive. It turns out, it’s also important for our happiness.
In NutureShock, Po Bronson and Ashley Merryman explain how sleep affects our positivity:
Negative stimuli get processed by the amygdala; positive or neutral memories gets processed by the hippocampus. Sleep deprivation hits the hippocampus harder than the amygdala. The result is that sleep-deprived people fail to recall pleasant memories, yet recall gloomy memories just fine.
In one experiment by Walker, sleep-deprived college students tried to memorize a list of words. They could remember 81% of the words with a negative connotation, like “cancer.” But they could remember only 31% of the words with a positive or neutral connotation, like “sunshine” or “basket.”
The BPS Research Digest explores another study that proves sleep affects our sensitivity to negative emotions. Using a facial recognition task over the course of a day, the researchers studied how sensitive participants were to positive and negative emotions. Those who worked through the afternoon without taking a nap became more sensitive late in the day to negative emotions like fear and anger.
Using a face recognition task, here we demonstrate an amplified reactivity to anger and fear emotions across the day, without sleep. However, an intervening nap blocked and even reversed this negative emotional reactivity to anger and fear while conversely enhancing ratings of positive (happy) expressions.
Of course, how well (and how long) you sleep will probably affect how you feel when you wake up, which can make a difference to your whole day. Especially this graph showing how your brain activity decreases is a great insight about how important enough sleep is for productivity and happiness:

Another study tested how employees’ moods when they started work in the morning affected their work day.
Researchers found that employees’ moods when they clocked in tended to affect how they felt the rest of the day. Early mood was linked to their perceptions of customers and to how they reacted to customers’ moods.
And most importantly to managers, employee mood had a clear impact on performance, including both how much work employees did and how well they did it.
Sleep is another topic we’ve looked into before, exploring how much sleep we really need to be productive.
3. Move closer to work – a short commute is worth more than a big house

Our commute to the office can have a surprisingly powerful impact on our happiness. The fact that we tend to do this twice a day, five days a week, makes it unsurprising that its effect would build up over time and make us less and less happy.
According to The Art of Manliness, having a long commute is something we often fail to realize will affect us so dramatically:
… while many voluntary conditions don’t affect our happiness in the long term because we acclimate to them, people never get accustomed to their daily slog to work because sometimes the traffic is awful and sometimes it’s not. Or as Harvard psychologist Daniel Gilbert put it, “Driving in traffic is a different kind of hell every day.”
We tend to try to compensate for this by having a bigger house or a better job, but these compensations just don’t work:
Two Swiss economists who studied the effect of commuting on happiness found that such factors could not make up for the misery created by a long commute.
4. Spend time with friends and family – don’t regret it on your deathbed

Staying in touch with friends and family is one of the top five regrets of the dying. If you want more evidence that it’s beneficial for you, I’ve found some research that proves it can make you happier right now.
Social time is highly valuable when it comes to improving our happiness, even for introverts. Several studies have found that time spent with friends and family makes a big difference to how happy we feel, generally.
I love the way Harvard happiness expert Daniel Gilbert explains it:
We are happy when we have family, we are happy when we have friends and almost all the other things we think make us happy are actually just ways of getting more family and friends.
George Vaillant is the director of a 72-year study of the lives of 268 men.
In an interview in the March 2008 newsletter to the Grant Study subjects, Vaillant was asked, “What have you learned from the Grant Study men?” Vaillant’s response: “That the only thing that really matters in life are your relationships to other people.”
He shared insights of the study with Joshua Wolf Shenk at The Atlantic on how the men’s social connections made a difference to their overall happiness:
The men’s relationships at age 47, he found, predicted late-life adjustment better than any other variable, except defenses. Good sibling relationships seem especially powerful: 93 percent of the men who were thriving at age 65 had been close to a brother or sister when younger.
In fact, a study published in the Journal of Socio-Economics states than your relationships are worth more than $100,000:
Using the British Household Panel Survey, I find that an increase in the level of social involvements is worth up to an extra £85,000 a year in terms of life satisfaction. Actual changes in income, on the other hand, buy very little happiness.
I think that last line is especially fascinating: Actual changes in income, on the other hand, buy very little happiness. So we could increase our annual income by hundreds of thousands of dollars and still not be as happy as if we increased the strength of our social relationships.
The Terman study, which is covered in The Longevity Project, found that relationships and how we help others were important factors in living long, happy lives:
We figured that if a Terman participant sincerely felt that he or she had friends and relatives to count on when having a hard time then that person would be healthier. Those who felt very loved and cared for, we predicted, would live the longest.
Surprise: our prediction was wrong… Beyond social network size, the clearest benefit of social relationships came from helping others. Those who helped their friends and neighbors, advising and caring for others, tended to live to old age.
5. Go outside – happiness is maximized at 13.9°C
In The Happiness Advantage, Shawn Achor recommends spending time in the fresh air to improve your happiness:
Making time to go outside on a nice day also delivers a huge advantage; one study found that spending 20 minutes outside in good weather not only boosted positive mood, but broadened thinking and improved working memory…
This is pretty good news for those of us who are worried about fitting new habits into our already-busy schedules. Twenty minutes is a short enough time to spend outside that you could fit it into your commute or even your lunch break.
A UK study from the University of Sussex also found that being outdoors made people happier:
Being outdoors, near the sea, on a warm, sunny weekend afternoon is the perfect spot for most. In fact, participants were found to be substantially happier outdoors in all natural environments than they were in urban environments.
The American Meteorological Society published research in 2011 that found current temperature has a bigger effect on our happiness than variables like wind speed and humidity, or even the average temperature over the course of a day. It also found that happiness is maximized at 13.9°C, so keep an eye on the weather forecast before heading outside for your 20 minutes of fresh air.
The connection between productivity and temperature is another topic we’ve talked about more here. It’s fascinating what a small change in temperature can do.
6. Help others – 100 hours a year is the magical number
One of the most counterintuitive pieces of advice I found is that to make yourself feel happier, you should help others. In fact, 100 hours per year (or two hours per week) is the optimal time we should dedicate to helping others in order to enrich our lives.
If we go back to Shawn Achor’s book again, he says this about helping others:
…when researchers interviewed more than 150 people about their recent purchases, they found that money spent on activities—such as concerts and group dinners out—brought far more pleasure than material purchases like shoes, televisions, or expensive watches. Spending money on other people, called “prosocial spending,” also boosts happiness.
The Journal of Happiness Studies published a study that explored this very topic:
Participants recalled a previous purchase made for either themselves or someone else and then reported their happiness. Afterward, participants chose whether to spend a monetary windfall on themselves or someone else. Participants assigned to recall a purchase made for someone else reported feeling significantly happier immediately after this recollection; most importantly, the happier participants felt, the more likely they were to choose to spend a windfall on someone else in the near future.
So spending money on other people makes us happier than buying stuff for ourselves. What about spending our time on other people? A study of volunteering in Germany explored how volunteers were affected when their opportunities to help others were taken away:
Shortly after the fall of the Berlin Wall but before the German reunion, the first wave of data of the GSOEP was collected in East Germany. Volunteering was still widespread. Due to the shock of the reunion, a large portion of the infrastructure of volunteering (e.g. sports clubs associated with firms) collapsed and people randomly lost their opportunities for volunteering. Based on a comparison of the change in subjective well-being of these people and of people from the control group who had no change in their volunteer status, the hypothesis is supported that volunteering is rewarding in terms of higher life satisfaction.
In his book Flourish: A Visionary New Understanding of Happiness and Well-being, University of Pennsylvania professor Martin Seligman explains that helping others can improve our own lives:
…we scientists have found that doing a kindness produces the single most reliable momentary increase in well-being of any exercise we have tested.
7. Practice smiling – it can alleviate pain
Smiling itself can make us feel better, but it’s more effective when we back it up with positive thoughts, according to this study:
A new study led by a Michigan State University business scholar suggests customer-service workers who fake smile throughout the day worsen their mood and withdraw from work, affecting productivity. But workers who smile as a result of cultivating positive thoughts – such as a tropical vacation or a child’s recital – improve their mood and withdraw less.
Of course it’s important to practice “real smiles” where you use your eye sockets. It’s very easy to spot the difference:

According to PsyBlog, smiling can improve our attention and help us perform better on cognitive tasks:
Smiling makes us feel good which also increases our attentional flexibility and our ability to think holistically. When this idea was tested by Johnson et al. (2010), the results showed that participants who smiled performed better on attentional tasks which required seeing the whole forest rather than just the trees.
A smile is also a good way to alleviate some of the pain we feel in troubling circumstances:
Smiling is one way to reduce the distress caused by an upsetting situation. Psychologists call this the facial feedback hypothesis. Even forcing a smile when we don’t feel like it is enough to lift our mood slightly (this is one example of embodied cognition).
One of our previous posts goes into even more detail about the science of smiling.
8. Plan a trip – but don’t take one
As opposed to actually taking a holiday, it seems that planning a vacation or just a break from work can improve our happiness. A study published in the journal, Applied Research in Quality of Life showed that the highest spike in happiness came during the planning stage of a vacation as employees enjoyed the sense of anticipation:
In the study, the effect of vacation anticipation boosted happiness for eight weeks.
After the vacation, happiness quickly dropped back to baseline levels for most people.
Shawn Achor has some info for us on this point, as well:
One study found that people who just thought about watching their favorite movie actually raised their endorphin levels by 27 percent.
If you can’t take the time for a vacation right now, or even a night out with friends, put something on the calendar—even if it’s a month or a year down the road. Then whenever you need a boost of happiness, remind yourself about it.
9. Meditate – rewire your brain for happiness
Meditation is often touted as an important habit for improving focus, clarity and attention span, as well as helping to keep you calm. It turns out it’s also useful for improving your happiness:
In one study, a research team from Massachusetts General Hospital looked at the brain scans of 16 people before and after they participated in an eight-week course in mindfulness meditation. The study, published in the January issue of Psychiatry Research: Neuroimaging, concluded that after completing the course, parts of the participants’ brains associated with compassion and self-awareness grew, and parts associated with stress shrank.
Meditation literally clears your mind and calms you down, it’s been often proven to be the single most effective way to live a happier live. I believe that this graphic explains it the best:

According to Shawn Achor, meditation can actually make you happier long-term:
Studies show that in the minutes right after meditating, we experience feelings of calm and contentment, as well as heightened awareness and empathy. And, research even shows that regular meditation can permanently rewire the brain to raise levels of happiness.
The fact that we can actually alter our brain structure through mediation is most surprising to me and somewhat reassuring that however we feel and think today isn’t permanent.
We’ve explored the topic of meditation and it’s effects on the brain in-depth before. It’s definitely mind-blowing what this can do to us.
10. Practice gratitude – increase both happiness and life satisfaction
This is a seemingly simple strategy, but I’ve personally found it to make a huge difference to my outlook. There are lots of ways to practice gratitude, from keeping a journal of things you’re grateful for, sharing three good things that happen each day with a friend or your partner, and going out of your way to show gratitude when others help you.
In an experiment where some participants took note of things they were grateful for each day, their moods were improved just from this simple practice:
The gratitude-outlook groups exhibited heightened well-being across several, though not all, of the outcome measures across the 3 studies, relative to the comparison groups. The effect on positive affect appeared to be the most robust finding. Results suggest that a conscious focus on blessings may have emotional and interpersonal benefits.
The Journal of Happiness studies published a study that used letters of gratitude to test how being grateful can affect our levels of happiness:
Participants included 219 men and women who wrote three letters of gratitude over a 3 week period.
Results indicated that writing letters of gratitude increased participants’ happiness and life satisfaction, while decreasing depressive symptoms.
For further reading, check out 7 Simple productivity tips you can apply today, backed by science, which goes even deeper into what we can do to be more grateful.
Quick last fact: Getting older will make yourself happier

As a final point, it’s interesting to note that as we get older, particularly past middle age, we tend to grow happier naturally. There’s still some debate over why this happens, but scientists have got a few ideas:
Researchers, including the authors, have found that older people shown pictures of faces or situations tend to focus on and remember the happier ones more and the negative ones less.
Other studies have discovered that as people age, they seek out situations that will lift their moods — for instance, pruning social circles of friends or acquaintances who might bring them down. Still other work finds that older adults learn to let go of loss and disappointment over unachieved goals, and hew their goals toward greater wellbeing.
So if you thought being old would make you miserable, rest assured that it’s likely you’ll develop a more positive outlook than you probably have now. 
Source & Author :  Belle Beth Cooper
A song to make you happy . . .

Monday, 25 November 2013

Train Yourself To Fall Asleep In Less Than 30 Seconds.


Does it take you a while to fall asleep at night? Do you find your mind dwelling on various thoughts before you’re able to finally drift off and relax into sleep? Do you find that you just aren’t sleepy enough when it’s time for bed?
Realize that if it takes you 15 minutes on average to fall asleep each night, that’s more than 91 hours per year that you’re wasting. This is the equivalent of spending more than two 40-hour workweeks just lying in bed waiting to fall asleep.
And if you have insomniac tendencies and take more than an hour to fall asleep each night, you’re spending more than nine 40-hour weeks on that pointless activity — every year. That’s a tremendous amount of wasted time.
If you’d like to change this situation, keep reading. I’ll explain the details and share a process for training your brain to fall asleep almost instantly when you’re ready to go to bed.

Drop Caffeine (at Least Initially)

First, if you drink coffee, tea (including green tea and white tea), yerba mate, cola, or any caffeinated beverages on a semi-regular basis, this method won’t work very well at all, so I strongly recommend that you get off all caffeine for at least 2 weeks before you attempt to make improvements in this area. Read How to Give Up Coffeeif you need help with that. I also advise that you drop chocolate during this time as well, including cocoa and cacao, since those contain stimulants too.
Even a small cup of coffee in the morning can disrupt your ability to fall asleep quickly at night. You may also sleep less restfully, and you’ll be prone to awaken more often throughout the night. Consequently, you may wake up tired and need extra sleep.
Simply eliminating all caffeine from your diet can improve your sleep habits tremendously. So if you haven’t already done that, please do that first before you attempt the training method I explain later in this article.
If you really love your caffeine though, the good news is that it’s okay to add it back once you’ve gone through this adaptation training. It will still disrupt your sleep a bit, but once you’ve mastered the habit of being able to fall asleep in 30 seconds or less, then most likely you’ll still be able to continue the habit even if you consume some caffeine during the day.

Train Your Brain to Fall Asleep Faster

A decade ago it might have taken me 15-30 minutes to fall asleep most nights. Sometimes it would take more than an hour if I had a lot on my mind. And very occasionally I could fall asleep within 5 minutes or less if I was very sleepy.
Today it’s fairly normal for me to fall asleep within 30 seconds or less, and often I’m able to fall asleep in less than 1 second. My best is probably around 1/4 of a second.
How do I know this? Because I have a witness that tells me how long I was out. I also know that I was sleeping because I awaken with the memory of a dream. If my sleep time is only a second or a fraction of a second, then it’s obviously a very short dream. Some time dilation occurs though, so a 1-second dream may feel significantly longer… perhaps as if 5-10 seconds have passed within the dream world.
Is this narcolepsy? No, narcolepsy is very different. I don’t just fall asleep at odd times throughout the day, and I don’t have excessive daytime sleepiness. Most days I don’t take any naps. One thing I do have in common with narcoleptics is that I can start having dreams immediately when I fall asleep, whereas most people don’t enter the dream state for at least an hour. I regard this as a positive adaptation though, not a problem or defect.
I can’t normally force myself to sleep when I’m not at all sleepy. But when I’m ready to go to sleep, I can go to sleep very quickly without wasting time trying to fall asleep.
I’m not able to do this 100% perfectly. If I have a stressful day and there’s a lot on my mind at night, I may find it more difficult to relax and go to sleep. But most of the time under normal, average conditions, I can get to sleep within 30 seconds or less.
I reached this point not by the exertion of conscious will but rather through a long-term process of sleep training. So don’t think that there’s some mental trick that you can use right away to make this happen instantly. However, once you’ve trained yourself to this point, the process is effortless. You’ll be able to do it automatically. It will be no more difficult than blinking.

Understanding the Training Process

The training process may take a long time — months or even years, depending on how far you want to go — but it’s not at all difficult, and it needn’t take a serious time commitment. In fact, the training will most likely save you a significant amount of time. The only challenging part is maintaining consistency long enough to get results.
First consider that it’s possible for you to fall asleep faster. Have you ever been really tired and sleepy at the end of a day, and you fell asleep very quickly after getting into bed? Have you ever drifted off while watching a movie or reading a book? Have you ever fallen asleep within less than 2 minutes after lying down? If you’ve done it before, then consider the possibility that your brain already knows how to fall asleep quickly, and if you create the right conditions, then you’re capable of doing this again. You just need to train your brain to do this more consistently.
The main reason that you aren’t falling asleep faster is that you haven’t trained your brain to do so. You may be able to reach that point eventually, but you’re not there yet. Similarly, you may be able to do the splits if you engage in flexibility training, but in the absence of such training, you probably won’t be able to do the splits at all.
If you want to fall asleep faster, you must incentivize your brain to drop all other activity and immediately transition into sleep when you desire to do so. That is the essence of this approach. If there are few consequences for a lazy approach to falling asleep, then your brain will continue to be lazy and inefficient in this area. You haven’t given it a good enough reason to select more efficient behaviors.
Your brain is always active, even during deep sleep, and it operates in different modes of consciousness, including beta (waking), alpha, theta, and delta phases. When you lie in bed waiting for sleep, you’re waiting for your brain to switch modes. An untrained brain will often take its own sweet time making the necessary state change. So you may dwell on other thoughts… or toss and turn… or just lie awake until your brain is finally ready to transition. This is a common experience. Without incentives to become more efficient, your brain will remain naturally lazy by default.
Your conscious mind might very much like to go to sleep, but it isn’t in charge. Your subconscious determines when you fall asleep. If your subconscious mind is in no hurry to fall asleep, then your conscious mind will have a hard time forcing it. In fact, your subconscious may continue to bubble up thoughts and ideas to occupy your conscious mind, distracting you with mental clutter instead of letting you relax and slide into sleep.
A trained subconscious mind is obedient and fast. When the conscious mind says to sleep, the subconscious activates sleep mode immediately. But this only works if you’re feeling at least partially sleepy. If the subconscious doesn’t agree with the need for sleep, it can still reject the request.
The process I’ll share next will teach your brain that putzing around isn’t an option anymore and that when you decide to go to sleep, it needs to transition immediately and without delay.

The Process

The process involves using short, timed naps to train your brain to fall asleep more quickly. Here’s how it works:
If and when you feel drowsy at some point during the day, give yourself permission to take a 20-minute nap. But only allow yourself exactly 20 minutes total. Use a timer to set an alarm. I often do this by using Siri on my iPhone by saying, “Set a timer for 20 minutes” or “Wake me up in 20 minutes.” The first one sets a countdown timer, while the later phrase sets an alarm to go off at a specific time. Sometimes I prefer to use a kitchen timer with a 20-minute countdown.
Begin the timer as soon as you lie down for your nap. Whether you sleep or not, and regardless of how long it takes you to fall asleep, you have 20 minutes total for this activity… not a minute more.
Simply relax and allow yourself to fall asleep as you normally would. You don’t have to do anything special here, so don’t try to force it. If you fall asleep, great. If you just lie there awake for 20 minutes, also great. And if you sleep for some fraction of the time, that’s perfectly okay too.
At the end of the 20 minutes, you must get up immediately. No lingering. This part is crucial. If you’re tempted to continue napping after the alarm goes off, then put the alarm across the room so you have to get up to turn it off. Or have someone else forcibly yank you off the couch or bed when they hear the alarm. But no matter what, get up immediately. The nap is over. If you’re still tired, you can take another nap later — wait at least an hour — but don’t let yourself go back to sleep right away.
I think it’s best to do your nap practice during the day if you can, but you can also do it in the evening, as long as it’s at least an hour before your normal bedtime. Perhaps the best time for an evening nap is right after dinner, when many people feel a little sleepy.
You don’t have to take the naps every day, but do them at least a few times a week if you can. I think the ideal practice would be one nap per day.
The next part of this process is to always wake up with an alarm in the morning. Set your alarm for a fixed time every day, seven days a week. When your alarm goes off each morning, get up immediately regardless of how much sleep you actually got. Again, no lingering. If you need help with this, read How to Become an Early Riser,How to Become an Early Riser – Part II, and How to Get Up Right Away When Your Alarm Goes Off. Those articles have helped many thousands of people improve their sleep habits.
Now when you go to bed at night, seek to go to bed at a time that will essentially require you to be sleeping the whole time you’re in bed in order to feel well rested in the morning. So if you feel you need a good 7 hours of sleep each night to feel rested, and you plan to get up at 5am every morning, then get yourself into bed and ready to sleep at about 10pm. If you take 30 minutes to fall asleep, then you’re getting less sleep than you need, and this is a disincentive to continuing that wasteful habit.
The message you’re sending to your brain is that the time you have to sleep is limited. You are going to get out of bed after a certain number of hours no matter what. You’re going to get up from your nap after a specific amount of time no matter what. So if your brain wants to sleep, it had better learn to go to sleep quickly and use the maximum time allotted for sleep. If it wastes time falling asleep, then it misses out on that extra sleep, and it will not have the opportunity to make it up by sleeping in later. Sleep time squandered is sleep time lost.
When you go to bed whenever and allow yourself to get up whenever, you reward your brain for continued laziness and inefficiency. It’s fine if you take a half hour to fall asleep since your brain knows it can just sleep in later. If you awaken with an alarm but go to bed earlier than necessary to compensate for the time it takes you to fall asleep, your still tell your brain that it’s fine to waste time transitioning to sleep because there’s still enough extra time to get the rest it needs.
Coffee and chocolate are also crutches because if you don’t get enough sleep, your brain can come to rely on a stimulant to keep it going when necessary. If you remove these outs, then your brain will soon connect the dots. It will learn that taking too long to fall asleep equals not getting enough sleep, which means going through the day tired and sleepy. By closing the door on potential outs like stimulants and extra snooze time, you leave only one remaining option for a solution. Sooner or later your brain will determine that going to sleep faster is indeed the solution, and it will adapt by transitioning into sleep much more quickly, so as to secure the full amount of rest it desires.
Instead of continuing to give your brain the message that oversleeping is okay or that stimulants are available, begin to condition it to understand that sleep time is a limited resource. Your brain is naturally good at optimizing scarce physiological resources; it evolved to do so over a long period of time. So if sleep time appears to be a limited resource, your brain can learn to optimize its use of this resource just as it has learned to optimize the use of oxygen and sugar.
If you get sleepy during the day as a result of limiting your sleep time at night, that’s perfectly okay. Take naps as needed. It’s okay to take multiple naps during the day if you need to, but keep them limited to 20 minutes max, and don’t have two naps within an hour of each other. Whenever you get up, stay up for at least an hour.
Once you get used to 20-minute naps — or if you don’t have that much time available for napping — try napping for shorter intervals. Give yourself 15, 10, or even 5 minutes for each nap. I sometimes take 3-4 minute naps (with a timer), which are surprisingly refreshing, but only if I fall asleep quickly.
Teach your brain that a 20-minute nap means 20 minutes of total time lying down. If your brain wants to ruminate during part of that time, it always means less sleep.
Also teach your brain that X number of hours in bed at night is all it gets, and so if it wants to get enough sleep, it had better spend virtually all of that time sleeping. If it spends time on non-sleep activity, it always robs itself of some sleep.
Once you’ve adapted and you’re able to fall asleep quickly when you desire to do so, you can slack off on the training process, ditch the alarm, and wake up whenever you want. Most likely the training will stick. You can even add the caffeine back if you so desire. But for a period of at least a couple months to start, I recommend being strict about it. Take naps regularly, and use an alarm to get up at a consistent time every single day.
I still prefer to get up with an alarm most days. I don’t need it to fall asleep quickly, but I tend to linger in bed more than necessary without the alarm.
If this is too strict for you, I doubt you’ll succeed with this approach. If you give your brain an easy out, it will take that out, and it won’t learn the adaptation you’re trying to teach it here.
Everyone is different, so how long it takes you to adapt depends on your particular brain. I’m sure some people will adapt fairly quickly, within a few weeks, while others may take significantly longer. There are many factors that can influence the results, with perhaps the biggest one being your diet. In general, a lighter, healthier, and more natural diet will make it significantly easier to adapt to any sort of sleep changes. Regular exercise also makes it easier to adapt to sleep changes; cardio exercise in particular helps to rebalance hormones and neurotransmitters, many of which are involved in regulating sleep cycles. If you eat a heavily processed diet (i.e. shopping mostly outside the produce section) and you don’t exercise much, just be aware that I rarely see such people succeed with worthwhile sleep changes of any kind.
One last item I’ll share is that I’m able to fall asleep fastest when I’m cuddling someone, both for naps and when going to bed at night. On my own I can get to sleep in under 30 seconds normally, but when I’m cuddling a nice warm female body, that’s when I can often get to sleep in less than a second. So I invite you to experiment with this if you have a willing cuddle partner who enjoys serving as a human teddy bear.