With more than 40 million downloads award-winning Calm app, founded by Michael Acton Smith and Alex Tew, is hugely popular. A meditation and mindfulness app, one of its key components is a library of sleep stories, many of which are penned by writer Phoebe Smith.

Therapists on welldoing.org can claim a free premium Calm membership by emailing [email protected] - this offer also extends to their welldoing.org clients.

We spoke to Calm's sleep storyteller-in-residence about wild sleeping, insomnia, and putting people to sleep.

How did this all come together with yourself, Sleep Stories and Calm?

I'm a writer so I'm not generally trying to put people to sleep with my words! But I had written a story about the Trans Siberian Railway and one of the co-founders of Calm, Michael Acton Smith, emailed me and said, "I really like your story - I think it would make a great story to send people to sleep". I asked him a bit more and he told me about his concept of Sleep Stories, which are bedtime stories but for adults.

At first I was sceptical, thinking it would just involve writing something really boring, but then I thought back to being a kid and the stories I wanted read to me weren't boring - quite the opposite - I wanted to hear them. What they need to do is be interesting enough to get someone to listen, but not so dramatic and exciting that they would keep people on the edge of their seat and wide awake. So I gave it a go, and they forwarded me the recording to approve. I listened to it after a long day, and I fell asleep! I was instantly convinced there was something in it and now I'm their Sleep Storyteller-in-Residence. So who knew, all these years I've been trying to keep people reading when it turns out I have a knack for sending people to sleep!

What makes a good Calm sleep story?

I think it always helps if there is some element of a journey, so trains are very popular, also meandering rivers. I'm writing one now about exploring the Oxford canal in a narrow boat - so slow and indulging in the journey itself, it's not about getting from A to B, it's about delighting in the whole process of getting there.

The first of my sleep stories were based on trips I had already done, but I always make notes when I travel, so I can refer back. I now go on trips specifically to write sleep stories so I travel a bit more mindfully; I allow myself the time to notice everything: the sounds, the smells, the feelings a place gives me. I used to pack a lot into my trips, but by taking longer in places means you notice more and get more from your experience. So writing Sleep Stories means I travel more mindfully too.

You're an explorer and wild sleeper also, can you tell me about that?

Yes, I like to find the strangest places to fall asleep! I've slept inside a glacier in Svalbard; I've slept in trees in Bavaria and Morocco and even dangling on a skyscraper in London. I'm all about the sleep, whether it's extreme or supreme.

I started wild sleeping about 12 years ago. Before that I thought that I was a "normal woman" who liked to spend the night in a bed with a warm duvet and then I was persuaded to sleep out in a roll away bed called a swag bag in Australia and just had the most incredible night watching the lights play on the rocks and the stars and wildlife come out, then waking up in the morning; from that point on I was addicted to sleeping in the wild.

Have you ever struggled with sleep?

Definitely! I find when I do my wild sleeping, I actually sleep really well. I think it's because I'm focused on being safe or staying warm and dry. When I'm actually in my own bed at home I can actually really struggle to sleep because you know I'm worried about deadlines, or emails or bills to pay - just those things that keep all of us from having a good nights sleep. So when Michael got in touch I was really keen to contribute; as someone who has suffered from bad insomnia, I thought wouldn't it be great if I could share my love of adventure and travel, use my skills in writing, and help people as well.