Duncan Teasdale, owner of My Fitness Hub gym in Havant, will be taking part in the 2018 Marathon des Sables in aid of Rowans Hospice.
The race, which happens in April, takes place in the Sahara Desert and consists of travelling 254km in six days, through blisteringly hot temperatures of more than 50 degrees Celsius.
But Duncan, 59 from Portsmouth, says he is looking forward to the challenge.
He said: ‘Being able to raise money for The Rowans Hospice is such a motivation to succeed.
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‘Having seen the amazing work carried out by the nurses and staff, I’ll be doing my very best to put in a positive performance and to help raise both awareness and donations for such an inspiring local charity.’
To support Duncan as he takes on one of the toughest challenges on the planet, people can go to justgiving.com/fundraising/duncan-marathon-des-sables.