Updated: May 16, 2019
Oscar Wilde wrote: "I never travel without my diary. One should always have something sensational to read on the train." World leaders, great thinkers and film stars have always kept journals, usually with the knowledge that one day they will be read by a shocked, amused and adoring public.
But a growing body of research is suggesting that we could all benefit from keeping a journal, if not for posterity, then for sanity and good health. Studies show that writing about your day, your feelings and your worries may not only clear your head - helping you to sleep, feel more relaxed and solve problems - it could even improve your physical health.
Researchers at the University of Arizona found that keeping a journal after a divorce not only helped people make sense of the experience emotionally and move forward, but also resulted in lower heart rate and higher heart rate variability - associated with better health. This builds on existing research being gathered by Dr James Pennebaker, author of Opening Up by Writing It Down, who has found that as well as lowering depression and anxiety, journaling strengthens immune cells called T-lymphocytes.
The theory is that by writing, you express and impose structure on anxious feelings, which in turn reduces stress and its physical impact on your body. And while many of us associate keeping a diary with our teenage years, research by the University of Lancaster suggests writing down your experiences helps you remember them later, so journals could be a useful tool to keep memory sharp as you age.
So should we all end every day with the words "Dear Diary"? "I recommend it to all my clients," says psychologist Dr Jane McCartney. "Writing something down stops things from going around and around in our heads. This puts things in perspective, it stops you from obsessing and can help us make sense of our jumble of thoughts and feelings. It's particularly useful for people who have problems sleeping. If you wake at 3am worrying about problems, just get them out on the page."
And if you're not a writer, don't worry, adds Dr McCartney. "You can doodle, do mind maps or lists. It doesn't have to be formal."
She is also a fan of the growing number of structured journals on sale that prompt reflection by asking questions, and giving you goals to fill in for the week, month or year. The Mind Journal is filled with questions and tasks, and is aimed specifically at men who find it hard to express their emotions.
Gretchen Rubin, meanwhile, author of The Happiness Project, has championed the idea of the one-sentence journal. Each night she writes at least one sentence about what happened that day in order to appreciate the little moments in her life.
Which brings us to another benefit of journaling, says psychotherapist Dr Lucy Beresford. "It can be a way of paying attention to life - a form of mindfulness," she says. "Life is so busy and it can go in a blur. Spending a few minutes taking a note of the little things can be very therapeutic."
Dr Beresford has personal experience of the benefits. "Four years ago, a friend gave me a blank book and on the first page she'd written, 'Things you're grateful for'. I started writing down little things. It gave me a different perspective; the chance to see that my life is great. I now do it every night."
And so, in the past three weeks, I have followed Dr Beresford's lead. I have always been one to fill notebooks with self-indulgent musings, which has been a great way to purge emotions. But I'm ringing the changes with a new, briefer form of journaling. First I'm listing three things I'm grateful for at the end of the day. Last night's trio: gorgeous sunshine, ice cream with maple syrup and a good hair day - "curls, not frizz!".
I've also started writing down the specifics, such as: "Made weird avocado and mint thing for dinner. Sent my first book out to publishers - terrifying and exciting."
And that is the joy of the journal - it can help you make sense of the big things and help you to savour the little. All of which makes for a full, rich life.
This was firsts reported on https://www.telegraph.co.uk/health-fitness/mind/dear-diary-surprising-health-benefits-journaling.