Sighthill watch manager Les hopes to be the first to run, swim, cycle and kayak in a straight line from Montrose in Angus to Ballachulish, Argyll.
The 38-year-old and his wife, Alana, 33, suffered four miscarriages after undergoing IVF.
Speaking about his marathon trek, Les said: “It’s the first time this unique route has ever been attempted. It’s my way of sticking a finger up at mother nature. When it comes to miscarriage, she calls the shots so this is a way for me to take on mother nature and win. Losing four babies has been tough but we got through it and I will do this.
“After each of our losses, I felt like a failure and ashamed for not being able to keep my baby safe when I spend my days saving the lives of others and keeping the public safe.
“People presume that if you’re married then you have kids. They treat you differently despite stillbirth and miscarriage being more common than people realise.
“I’m doing this because everyone needs to be more open about the subject. Some folk say ‘it wasn’t meant to be’ – would they say that about any other medical event that devastates you and your future hopes and dreams?”
Les, who previously trekked across the Arctic Circle, said: “I chose this specific route as it is doable in a 24-hour period, albeit very challenging to achieve in that timescale.
“It is a natural corridor that stretches through the southern Highlands and encompasses a landscape that lends itself to cycling, swimming, kayaking and running in a westerly direction.”
He said: “It’s no easy task but, as a firefighter, I have planned and risk-assessed everything to the final letter.
“I am being supported by former firefighter Lee Peyton, who runs Breaking Strain Events and has lots of experience tackling difficult challenges. I have also had great backing from our main sponsor, Glenturret Whisky.
“The miscarriages made me feel helpless but by doing the challenge I am now helping others and don’t feel so useless.”
Property adviser Alana, added: “After the last miscarriage, we decided to stop and breathe. We had been living month to month for four years. We are not going to let it dictate our lives but we are saving up for private IVF.”
Les has called the challenge Chasing Our Rainbow as children born after miscarriage are often called rainbow babies.
He said: “Organising the challenge has helped me put my feelings in order and I’ve been surprised at how many friends and colleagues have shared their experiences of miscarriage. Hopefully one day we’ll have our own rainbow baby. We won’t give up hope.”
See more at www.breakingstrain.co.uk/chasing-our-rainbow/